Zur Problematik von Blind-Studien

 

AN     14761905

AU     Fergusson D, Glass KC, Waring D, Shapiro S

TI      Turning a blind eye: the success of blinding reported in a random sample of randomised, placebo controlled trials.[see comment]. [Review] [4 refs]

IN      Ottawa Health Research Institute, Clinical Epidemiology Program, 501 Smyth Road, Box 201, Ottawa, ON, Canada K1H 8L6. dafergusson@ohri.ca

SO     BMJ. 328(7437):432, 2004 Feb 21.

CM     Comment in: BMJ. 2004 May 8;328(7448):1135-6; author reply 1136; PMID: 15130996, Comment in: BMJ. 2004 May 8;328(7448):1135; author reply 1136; PMID: 15130995, Comment in: BMJ. 2004 May 8;328(7448):1136; PMID: 15130997

PT      Publication Type: Journal Article; Review; Review Literature

AB     OBJECTIVE: To examine the reporting and success of double blinding in a sample of randomised, placebo controlled trials from leading general medicine and psychiatry journals. METHODS: Identification of placebo controlled, randomised controlled trials from prespecified general medical and psychiatric journals indexed on Medline between 1 January 1998 and 1 October 2001, from which a random sample of 200 randomised clinical trials was chosen, of which 191 trials were evaluated. RESULTS: Only seven of the 97 (7%) general medicine trials provided evidence on the success of blinding, with five reporting that the success of blinding was imperfect. In trials from psychiatric journals, the success of blinding was reported in eight of the 94 trials, with four reporting that the blinding was imperfect. Overall, only four of the 191 (2%) trials assessed blinding in the participants and either the outcome assessors or the investigators. CONCLUSIONS: The current lack of reporting on the success of blinding provides little evidence that success of blinding is maintained in placebo controlled trials. Trialists and editors should make a concerted effort to incorporate, report, and publish such information and its potential effect on study results. [References: 4]

DE     Descriptors: *Double-Blind Method; *Randomized Controlled Trials/mt [Methods]; Randomized Controlled Trials/st [Standards]; Support, Non-U.S. Gov't

 

 

AN     15135549

AU     Mooney M, White T, Hatsukami D

TI      The blind spot in the nicotine replacement therapy literature: assessment of the double-blind in clinical trials. [Review] [49 refs]

IN      Tobacco Use Research Center, University of Minnesota, 2701 University Avenue S.E., Suite 201, Minneapolis, MN 55414, USA. Marc.E.Mooney@uth.tmc.edu

SO     Addictive Behaviors. 29(4):673-84, 2004 Jun.

PT      Publication Type: Journal Article; Meta-Analysis; Review; Review, Academic

AB     While clinical trials of medications often use a double-blind procedure, the integrity of the blind and its relationship to treatment outcome is seldom examined. In this review, 73 double-blind, placebo-controlled clinical trials of the nicotine replacement therapies (NRTs) in smoking cessation were identified. Seventeen articles were found that assessed blindness integrity, demonstrating major variations in the assessment, analysis, and reporting of blindness integrity. Although 12 studies found that subjects accurately judged treatment assignment at a rate significantly above chance, the available literature does not permit definitive conclusions about blindness integrity. Recommendations for the assessment, analysis, and reporting of blindness integrity are made. [References: 49]

DE     Descriptors: Controlled Clinical Trials; *Double-Blind Method; Human; *Nicotine/tu [Therapeutic Use]; *Nicotinic Agonists/tu [Therapeutic Use]; *Smoking Cessation/mt [Methods]; Support, U.S. Gov't, P.H.S.

 

 

AN     2004120432

AU     Bang H, Ni L, Davis CE

TI      Assessment of blinding in clinical trials.

IN      H. Bang, Department of Biostatistics, Univ. of N. Carolina at Chapel Hill, 137 E. Franklin Street, Chapel Hill, NC 27599; United States.  E-Mail: heejung_bang@unc.edu.

SO     Controlled Clinical Trials. Vol. 25(2)(pp 143-156), 2004.

PT      Publication Type: Journal: Article

AB     Success of blinding is a fundamental issue in many clinical trials. The validity of a trial may be questioned if this important assumption is violated. Although thousands of ostensibly double-blind trials are conducted annually and investigators acknowledge the importance of blinding, attempts to measure the effectiveness of blinding are rarely discussed. Several published papers proposed ways to evaluate the success of blinding, but none of the methods are commonly used or regarded as standard. This paper investigates a new approach to assess the success of blinding in clinical trials. The blinding index proposed is scaled to an interval of -1 to 1, 1 being complete lack of blinding, 0 being consistent with perfect blinding and -1 indicating opposite guessing which may be related to unblinding. It has the ability to detect a relatively low degree of blinding, response bias and different behaviors in two arms. The proposed method is applied to a clinical trial of cholesterol-lowering medication in a group of elderly people. (C) 2004 Elsevier Inc. All rights reserved.

DE     Descriptors: *Hypocholesterolemic Agent; Placebo; *Double Blind Procedure; *Single Blind Procedure; *Clinical Trial; Validation Process; Evaluation; Simulation; Mathematical Model; Article

 

 

AN     15083477

AU     Chow SC, Shao J

TI      Analysis of clinical data with breached blindness.

IN      Millennium Pharmaceuticals Inc., Cambridge, MA 02139, U.S.A.

SO     Statistics in Medicine. 23(8):1185-93, 2004 Apr 30.

PT      Publication Type: Journal Article

AB     In clinical trials, blinding is usually employed to prevent bias that may be introduced due to the knowledge of the identity of the treatment codes. This bias could alter the conclusion of statistical inference on the treatment effect. The purpose of this article is to propose a method for analysing clinical data with breached blindness. The example regarding the study of the effectiveness of an appetite suppressant in weight loss in obese woman as described in Brownell and Stunkard (Am. J. Psychiatry 1982; 139:1487-1489) is used to illustrate the application of the proposed methods. Copyright 2004 John Wiley & Sons, Ltd.

DE     Descriptors: Analysis of Variance; Appetite Depressants/tu [Therapeutic Use]; Bias (Epidemiology); *Data Interpretation, Statistical; *Double-Blind Method; Female; Human; Models, Statistical; Obesity/dt [Drug Therapy]; *Randomized Controlled Trials/mt [Methods]; Randomized Controlled Trials/sn [Statistics & Numerical Data]; Research Design; Treatment Outcome

 

 

AN     14608321

AU     Bridgman S, Engebretsen L, Dainty K, Kirkley A, Maffulli N, ISAKOS Scientific Committee

TI      Practical aspects of randomization and blinding in randomized clinical trials.[erratum appears in Arthroscopy. 2004 Mar;20(3):A14].

IN      Orthopaedic Surgical Trial Unit, Stoke-on-Trent, Staffordshire, England, UK.

SO     Arthroscopy. 19(9):1000-6, 2003 Nov.

PT      Publication Type: Journal Article

AB     Randomization and blinding are important tools in determining the effectiveness of a new intervention and ensuring the validity of a clinical trial. However, randomness and haphazardness are not equivalent. Randomization cannot overcome poor experimental design or technique. Several types of randomization including historical controls and pseudorandomization are discussed, as well as methods of treatment allocation, stratification, and minimization techniques. The importance of decreasing bias and the advantages and disadvantages of blinding in randomized clinical trials are also covered.

DE     Descriptors: Bias (Epidemiology); Control Groups; *Double-Blind Method; Human; *Random Allocation; Randomized Controlled Trials/mt [Methods]; *Randomized Controlled Trials/sn [Statistics & Numerical Data]; Sampling Studies; *Single-Blind Method

 

 

AN     14629838

AU     Stambolovic V

TI      Blind trial: a subjugation tool.

SO     Journal of Alternative & Complementary Medicine. 9(5):615-7, 2003 Oct.

PT      Publication Type: Letter

DE     Descriptors: Complementary Therapies/mt [Methods]; *Complementary Therapies/st [Standards]; *Controlled Clinical Trials/st [Standards]; *Double-Blind Method; Human; Quality Assurance, Health Care; Research Design/st [Standards]

 

 

AN     12707479

AU     Sharpe L, Ryan B, Allard S, Sensky T

TI      Testing for the integrity of blinding in clinical trials: how valid are forced choice paradigms?.

IN      School of Psychology, Clinical Psychology Unit F12, University of Sydney, Australia. louises@psych.usyd.edu.au

SO     Psychotherapy & Psychosomatics. 72(3):128-31, 2003 May-Jun.

PT      Publication Type: Journal Article

AB     BACKGROUND: In randomised controlled trials, an increasingly used test of the 'blindness' of assessors is to have them guess the group to which each participant has been allocated. Because assessors are usually aware of the trial hypotheses, we predicted that trial participants who showed the greatest improvement would be assumed by an assessor to have been in the 'preferred intervention' group. METHODS: Data were derived from a trial in recent-onset rheumatoid arthritis comparing cognitive behavioural therapy plus routine care with routine care alone. RESULTS: Although in this trial assessor blindness was demonstrated, patients 'guessed' by the assessor to be in the cognitive therapy group showed significantly greater improvements than those predicted to have received routine care alone in variables predicted to change in the study protocol. CONCLUSIONS: These results indicate that even if an assessor's guesses about patient group allocations are more accurate than expected by chance, this would not necessarily demonstrate failure of blinding. This casts further doubt on the validity of forced choice paradigms in testing the integrity of blinding in clinical trials. Copyright 2003 S. Karger AG, Basel

DE     Descriptors: Arthritis, Rheumatoid/px [Psychology]; Arthritis, Rheumatoid/th [Therapy]; Cognitive Therapy; *Double-Blind Method; Human; *Randomized Controlled Trials; Reproducibility of Results; Research Design; Support, Non-U.S. Gov't

 

 

AN     11829579

AU     Devereaux PJ, Bhandari M, Montori VM, Manns BJ, Ghali WA, Guyatt GH

TI      Double blind, you are the weakest link--good-bye!.

SO     ACP Journal Club. 136(1):A11, 2002 Jan-Feb.

PT      Publication Type: Editorial

DE     Descriptors: *Double-Blind Method; Human; Randomized Controlled Trials/mt [Methods]; Randomized Controlled Trials/st [Standards]

 

 

AN     12088981

AU     Flanagan N, Sherrington C

TI      Effectiveness of blinding when comparing nitrous oxide with topical anesthetic cream.[comment].

SO     Anesthesia & Analgesia. 95(1):251; author reply 251, 2002 Jul.

CM     Comment on: Anesth Analg. 2001 Sep;93(3):590-3; PMID: 11524323

PT      Publication Type: Comment; Letter

DE     Descriptors: Administration, Topical; *Anesthesia, Inhalation; *Anesthesia, Local; *Anesthetics, Inhalation; *Anesthetics, Local; *Double-Blind Method; Human; *Nitrous Oxide; *Randomized Controlled Trials/mt [Methods]; Research Design

 

 

AN     11964621

AU     Park J, Lee H, White A, Ernst E

TI      Suggesting an alternative to the term "double-blind".

SO     Anesthesiology. 96(4):1034; author reply 1035, 2002 Apr.

PT      Publication Type: Letter

DE     Descriptors: Acupuncture Analgesia; *Double-Blind Method; Human; Pain, Postoperative/th [Therapy]; Terminology

 

 

AN     2002116060

AU     Devereaux PJ, Bhandari M, Montori VM, Manns BJ, Ghali WA, Guyatt GH

TI      'Double blind, you are the weakest link - Goodbye!'.

IN      Dr. P.J. Devereaux, McMaster University, Hamilton, Ont.; Canada.

SO     Evidence Based Medicine. Vol. 7(1)(pp 4-6), 2002.

PT      Publication Type: Journal: Article

DE     Descriptors: *Medical Research; *Double Blind Procedure; Methodology; Validation Process; Clinical Study; Medical Information; Treatment Planning; Health Practitioner; Outcomes Research; Data Analysis; Decision Making; Clinical Practice; Human; Controlled Study; Article

 

 

AN     12026889

AU     Devereaux PJ, Bhandari M, Montori VM, Manns BJ, Ghall WA, Guyatt GH

TI      Double blind, you have been voted off the island!.

IN      McMaster University, Hamilton, Ontario, Canada.

SO     Evidence-Based Mental Health. 5(2):36-7, 2002 May.

PT      Publication Type: Journal Article

DE     Descriptors: *Double-Blind Method; *Randomized Controlled Trials

 

 

AN     12384193

AU     Montori VM, Bhandari M, Devereaux PJ, Manns BJ, Ghali WA, Guyatt GH

TI      In the dark: the reporting of blinding status in randomized controlled trials.

IN      Department of Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. montori.victor@mayo.edu

SO     Journal of Clinical Epidemiology. 55(8):787-90, 2002 Aug.

PT      Publication Type: Journal Article

AB     To determine the quality of reporting of blinding in randomized controlled trials (RCTs), we evaluated 40 consecutive RCTs published in each of five leading journals. We noted whether authors reported the blinding status of participants, health care providers, data collectors, judicial assessors of outcomes, data analysts, and manuscript writers. Explicit reporting of blinding status occurred in <25% of RCTs for all groups. Eighty-three RCTs, reported as double-blind, provided eight combinations of blinded groups. In conclusion, prestigious journals do not currently report blinding status optimally. To do so, journals should abandon the term "double blind" and explicitly report the blinding status of the groups involved in RCTs. Until such reporting occurs, clinicians will be left with uncertainty about the validity of RCTs that guide their clinical practice.

DE     Descriptors: Bias (Epidemiology); *Double-Blind Method; Human; Journalism, Medical/st [Standards]; *Journalism, Medical; Quality Control; *Randomized Controlled Trials/mt [Methods]; *Randomized Controlled Trials/st [Standards]; Research Design/st [Standards]; *Single-Blind Method; United States

 

 

AN     2002100901

AU     Rodriguez Martin JL, Casado Collado A

TI      Double-blind. The bias control in the performance of clinical trials. Contradictions, lacks and implications.

IN      Dr. J.L. Rodriguez Martin, Centro Cochrane Iberoamericano, Servei d'Epidemiol. Clin. Salut Pub., Hosp. de la Santa Creu i Sant Pau, Sant Antoni M. Claret 171, 08041 Barcelona; Spain.  E-Mail: jrodriguezma@hsp.santpau.es.

SO     Medicina Clinica. Vol. 118(5)(pp 192-195), 2002. Date of Publication: 16 FEB 2002.

PT      Publication Type: Journal: Article

DE     Descriptors: *Double Blind Procedure; *Clinical Trial; Epidemiology; Methodology; Meta Analysis; Cochrane Library; Human; Controlled Study; Article

 

 

AN     12353521

AU     Mercer J

TI      The difficulties of double blinding.[comment].

SO     Science. 297(5590):2208, 2002 Sep 27.

CM     Comment on: Science. 2002 Jul 19;297(5580):325-6; PMID: 12130763

PT      Publication Type: Comment; Letter

DE     Descriptors: *Double-Blind Method; Estrogen Replacement Therapy/ae [Adverse Effects]; *Estrogen Replacement Therapy; Female; Human; Patient Compliance; Placebos; *Randomized Controlled Trials

 

 

AN     11707879

AU     Schulz KF

TI      Assessing allocation concealment and blinding in randomised controlled trials: why bother?.

SO     Evidence-Based Nursing. 4(1):4-6, 2001 Jan.

PT      Publication Type: Editorial

AB     As users of RCT results, we must understand the potential for humans to interject bias. By describing assessments of allocation concealment and blinding, abstracts included in Evidence-Based Nursing will help readers to discern those trials that have made superior efforts to minimise bias. Judging the quality of allocation concealment and blinding reflects current empirical research and reflects the commitment of the editors of this journal to apply the principles of evidence-based practice to reporting of study findings.

DE     Descriptors: *Double-Blind Method; Human; Random Allocation; Randomized Controlled Trials/mt [Methods]; *Randomized Controlled Trials/st [Standards]

 

 

AN     2001217108

AU     Anonymous

TI      Code breaking in double-blind trials.

SO     Good Clinical Practice Journal. Vol. 8(6)(pp 21), 2001.

PT      Publication Type: Journal: Note

DE     Descriptors: *Good Clinical Practice; *Double Blind Procedure; *Medical Ethics; Drug Safety; Drug Information; Monitoring; Practice Guideline; Randomization; Professional Standard; Clinical Protocol; General and Miscellaneous Procedures and Techniques; Patient Monitoring; Note

 

 

AN     11308438

AU     Devereaux PJ, Manns BJ, Ghali WA, Quan H, Lacchetti C, Montori VM, Bhandari M, Guyatt GH

TI      Physician interpretations and textbook definitions of blinding terminology in randomized controlled trials.[see comment].

IN      Department of Medicine, McMaster University, 1200 Main St W, Room 2C12, Hamilton, Ontario, Canada L8N 3Z5. philipj@mcmaster.ca

SO     JAMA. 285(15):2000-3, 2001 Apr 18.

CM     Comment in: JAMA. 2001 Apr 18;285(15):2006-7; PMID: 11308440

PT      Publication Type: Journal Article

AB     CONTEXT: When clinicians assess the validity of randomized controlled trials (RCTs), they commonly evaluate the blinding status of individuals in the RCT. The terminology authors often use to convey blinding status (single, double, and triple blinding) may be open to various interpretations. OBJECTIVE: To determine physician interpretations and textbook definitions of RCT blinding terms. DESIGN AND SETTING: Observational study undertaken at 3 Canadian university tertiary care centers between February and May 1999. PARTICIPANTS: Ninety-one internal medicine physicians who responded to a survey. MAIN OUTCOME MEASURES: Respondents identified which of the following groups they thought were blinded in single-, double-, and triple-blinded RCTs: participants, health care providers, data collectors, judicial assessors of outcomes, data analysts, and personnel who write the article. Definitions from 25 systematically identified textbooks published since 1990 providing definitions for single, double, or triple blinding. RESULTS: Physician respondents identified 10, 17, and 15 unique interpretations of single, double, and triple blinding, respectively, and textbooks provided 5, 9, and 7 different definitions of each. The frequencies of the most common physician interpretation and textbook definition were 75% (95% confidence interval [CI], 65%-83%) and 74% (95% CI, 52%-90%) for single blinding, 38% (95% CI, 28%-49%) and 43% (95% CI, 24%-63%) for double blinding, and 18% (95% CI, 10%-28%) and 14% (95% CI, 0%-58%) for triple blinding, respectively. CONCLUSIONS: Our study suggests that both physicians and textbooks vary greatly in their interpretations and definitions of single, double, and triple blinding. Explicit statements about the blinding status of specific groups involved in RCTs should replace the current ambiguous terminology.

DE     Descriptors: *Double-Blind Method; *Publishing/st [Standards]; *Randomized Controlled Trials/st [Standards]; *Single-Blind Method; Support, Non-U.S. Gov't; *Terminology

 

 

AN     2001183265

AU     Kaptchuk TJ

TI      The double-blind, randomized, placebo-controlled trial: Gold standard or golden calf?.

IN      T.J. Kaptchuk, Beth Israel Deaconess Medical Center, Harvard Medical School, KW-400, 330 Brookline Avenue, Boston, MA 02215; United States.

SO     Journal of Clinical Epidemiology. Vol. 54(6)(pp 541-549), 2001.

PT      Publication Type: Journal: Review

AB     The double-blind randomized controlled trial (RCT) is accepted by medicine as objective scientific methodology that, when ideally performed, produces knowledge untainted by bias. The validity of the RCT rests not just on theoretical arguments, but also on the discrepancy between the RCT and less rigorous evidence (the difference is sometimes considered an objective measure of bias). A brief overview of historical and recent developments in 'the discrepancy argument' is presented. The article then examines the possibility that some of this 'deviation from truth' may be the result of artifacts introduced by the masked RCT itself. Can an 'unbiased' method produce bias? Among the experiments examined are those that augment the methodological stringency of a normal RCT in order to render the experiment less susceptible to subversion by the mind. This methodology, a hypothetical 'platinum' standard, can be used to judge the 'gold' standard. The concealment in a placebo-controlled RCT seems capable of generating a 'masking bias.' Other potential biases, such as 'investigator self-selection,' 'preference,' and 'consent' are also briefly discussed. Such potential distortions indicate that the double-blind RCT may not be objective in the realist sense, but rather is objective in a 'softer' disciplinary sense. Some 'facts' may not exist independent of the apparatus of their production. (C) 2001 Elsevier Science Inc.

DE     Descriptors: *Placebo; *Double Blind Procedure; *Randomized Controlled Trial; Validation Process; Science; Artifact; Apparatus; Outcomes Research; Informed Consent; Alertness; Tension; Motor Performance; Pulse Rate; Systolic Blood Pressure; Coffee; Human; Human Experiment; Normal Human; Controlled Study; Review; Priority Journal

 

 

AN     11379846

AU     Kumar S, Oakley-Browne M

TI      Problems with ensuring a double blind.[comment].

SO     Journal of Clinical Psychiatry. 62(4):295-6, 2001 Apr.

CM     Comment on: J Clin Psychiatry. 2000 Jan;61(1):26-9; PMID: 10695642

PT      Publication Type: Comment; Letter

DE     Descriptors: Comparative Study; Cyclohexanols/tu [Therapeutic Use]; Delusions/dt [Drug Therapy]; Delusions/px [Psychology]; Depressive Disorder/dt [Drug Therapy]; Depressive Disorder/px [Psychology]; *Double-Blind Method; Fluvoxamine/tu [Therapeutic Use]; Human; Randomized Controlled Trials/st [Standards]; *Research Design/st [Standards]; Serotonin Uptake Inhibitors/tu [Therapeutic Use]

 

 

AN     11782039

AU     Friede T, Kieser M

TI      A comparison of methods for adaptive sample size adjustment.

IN      Medical Biometry Unit, University of Heidelberg, Im Neuenheimer Feld 305, 69120 Heidelberg, Germany.

SO     Statistics in Medicine. 20(24):3861-73, 2001 Dec 30.

PT      Publication Type: Journal Article

AB     In fixed sample size designs, precise knowledge about the magnitude of the outcome variable's variance in the planning phase of a clinical trial is mandatory for an adequate sample size determination. Wittes and Brittain introduced the internal pilot study design that allows recalculation of the sample size during an ongoing trial using the estimated variance obtained from an interim analysis. However, this procedure requires the unblinding of the treatment code. Since unblinding of an ongoing trial should be avoided whenever possible, there should be some benefit of this design compared with blinded sample size recalculation procedures to justify the unveiling of the treatment code. In this paper, we compare several sample size recalculation procedures with and without unblinding. The simulation results indicate that the procedures behave similarly. In particular, breaking of the blind is not required for an efficient sample size adjustment. We also compare these pure sample size adaptation procedures with study designs which additionally allow for early stopping. Evaluation of the cumulative distribution function of the resulting sample sizes shows that the option for early stopping may lead to lower expectation but generally to a higher variability. The procedures are illustrated by an example of a trial in the treatment of depression. Copyright 2001 John Wiley & Sons, Ltd.

DE     Descriptors: Comparative Study; Computer Simulation; Depression/dt [Drug Therapy]; *Double-Blind Method; Human; Hypericum/me [Metabolism]; Phytotherapy; *Randomized Controlled Trials/mt [Methods]; *Sample Size; Support, Non-U.S. Gov't

 

 

AN     10948038

AU     Day SJ, Altman DG

TI      Statistics notes: blinding in clinical trials and other studies. [Review] [4 refs]

IN      Leo Pharmaceuticals, Princes Risborough, Buckinghamshire HP27 9RR.

SO     BMJ. 321(7259):504, 2000 Aug 19-26.

PT      Publication Type: Journal Article; Review; Review, Tutorial

DE     Descriptors: *Clinical Trials/mt [Methods]; *Double-Blind Method; Human; Single-Blind Method

 

 

AN     10945088

AU     Even C, Siobud-Dorocant E, Dardennes RM

TI      Critical approach to antidepressant trials. Blindness protection is necessary, feasible and measurable. [Review] [22 refs]

IN      Clinique des Maladies Mentales et de l'Encephale, Centre Hospitalier Sainte-Anne, Paris, France.

SO     British Journal of Psychiatry. 177:47-51, 2000 Jul.

PT      Publication Type: Journal Article; Review; Review Literature

AB     BACKGROUND: Double-blind placebo-controlled trials are the academic standard for clinical psychopharmacology research. AIMS: To identify the potential defects of current double-blind procedures in trials involving antidepressants and to investigate whether safeguards for blindness protection are used. METHOD: We reviewed the literature and devised a short seven-item checklist for evaluating the quality of blindness protection. We performed a computerised search for 1998 to identify the placebo-controlled studies that evaluated the efficacy of an antidepressant. The checklist was used to assess all traceable antidepressant trials published in 1998. RESULTS: Relevant criticisms question the blindness procedures. The available methods which may bolster blindness are very seldom used. CONCLUSIONS: Improvement in the blindness procedures used for antidepressant trials is necessary, feasible and measurable. [References: 22]

DE     Descriptors: *Antidepressive Agents/tu [Therapeutic Use]; *Controlled Clinical Trials/mt [Methods]; *Depressive Disorder/dt [Drug Therapy]; *Double-Blind Method; Human; Placebos; Retrospective Studies

 

 

AN     2000373748

AU     Gissane C, Eston R, Rowlands A

TI      Who should be blinded? (multiple letters) [2].

IN      C. Gissane, Department of Health Studies, Brunel University, Osterley Campus, Isleworth, Middlesex TW7 5DU; United Kingdom.

SO     British Journal of Sports Medicine. Vol. 34(5)(pp 403), 2000.

PT      Publication Type: Journal: Letter

DE     Descriptors: *Medical Research; *Single Blind Procedure; *Double Blind Procedure; Methodology; Medical Literature; Sports Medicine; Randomized Controlled Trial; Outcomes Research; Publication; Stretching; Exercise; Leg Injury; General Practitioner; Clinical Practice; Human; Letter

 

 

AN     11624657

AU     Marks HM

TI      Trust and mistrust in the marketplace: statistics and clinical research, 1945-1960.

IN      Johns Hopkins University, Baltimore, MD, USA.

SO     History of Science. 38 Pt 3(121):343-55, 2000 Sep.

PT      Publication Type: Historical Article; Journal Article

DE     Descriptors: *Clinical Protocols; *Double-Blind Method; History of Medicine, 20th Cent.; *Random Allocation; Risk; *Statistics/hi [History]

 

 

AN     11152048

AU     Jobst KA

TI      Blinding and the tapestry of trial design: revealing the weaving and the woven.

SO     Journal of Alternative & Complementary Medicine. 6(6):475-7, 2000 Dec.

PT      Publication Type: Editorial

DE     Descriptors: *Clinical Trials; *Complementary Therapies; *Double-Blind Method; Human; Placebo Effect

 

 

AN     11152049

AU     Reilly D

TI      The unblind leading the blind: the Achilles heel of too many trials.

SO     Journal of Alternative & Complementary Medicine. 6(6):479-80, 2000 Dec.

PT      Publication Type: Editorial

DE     Descriptors: *Clinical Trials; *Double-Blind Method; Human; Placebo Effect

 

 

AN     11152053

AU     Caspi O, Millen C, Sechrest L

TI      Integrity and research: introducing the concept of dual blindness. how blind are double-blind clinical trials in alternative medicine?. [Review] [43 refs]

IN      Department of Psychology, University of Arizona, Tucson, USA. ocaspi@ahsc.arizona.edu

SO     Journal of Alternative & Complementary Medicine. 6(6):493-8, 2000 Dec.

PT      Publication Type: Journal Article; Review; Review, Tutorial

AB     Double-blind methodology is used in clinical studies to control for potential external or nonspecific influences such as belief and expectation, as well as to maintain as much objectivity as possible on the part of the researchers. Despite not being feasible in all medical disciplines, as in the case of some modalities of complementary and alternative medicine, there are numerous studies that spuriously claim its use. Distinctions and standards therefore need to be set to avoid misleading information. We propose a new term in research methodology, dual-blind, to describe a methodological alternative in which the caregiver is not blind but the patient and an external evaluator/investigator are. The term double-blind should be used strictly to describe a methodology in which both the patient and the caregiver are blind. Making the distinction between these two terms will result in more reliable reports of clinical trials and will support integrity in research. [References: 43]

DE     Descriptors: Bias (Epidemiology); Caregivers; *Clinical Trials; Complementary Therapies; *Double-Blind Method; Human; Patients; Placebo Effect

 

 

AU     Beck P

TI      Single blind placebo in drug research.

SO     J Med Ethics 2000 Dec;26(6):477.

LG      eng

PT      Publication Type: Comment; Letter

DE     Descriptors: Clinical Trials/*methods; Drug Evaluation/*standards; Human; *Human Experimentation; Placebos/*standards; *Single-Blind Method; United States

 

 

AU     Evans M

TI      Justified deception? The single blind placebo in drug research.

IN      Centre for Philosophy and Health Care, School of Health Science, University of Wales Swansea.

SO     J Med Ethics 2000 Jun;26(3):188-93.

LG      eng

PT      Publication Type: Journal Article

AB     "Run-in" and "washout" periods involving the withholding of medication are widely used in drug research trials in pursuit of both patient safety and scientific reliability. Such no-medication periods can be justified ethically provided that they are apparent to patients, who can thereby properly consent to undergoing them. Less widespread, but still common, is the practice of "single blinding" no-medication periods, concealing them from patients by means of placebo. Whilst all placebos involve a measure of concealment, their use is typically justified in drug research trials (i) by their preserving the uncertainty generated by the random allocation of different treatments within a drug trial; and (ii) by the researchers openly declaring both the randomisation process and the chances of receiving placebo. In the single blind placebo "run-in" or "washout", neither of these conditions is met. This paper considers three possible defences of the practice of using single blind placebo "run-ins" or "washouts" and finds them all to fail; the practice appears ethically unjustified.

DE     Descriptors: Clinical Trials/*legislation & jurisprudence; *Deception; *Ethics, Medical; Human; Informed Consent/legislation & jurisprudence; Morals; Research Subjects; *Single-Blind Method; Therapeutic Human Experimentation

 

 

AN     10234873

AU     Sheldrake R

TI      How widely is blind assessment used in scientific research?.

IN      Institute of Noetic Sciences, Sausalito, Calif., USA.

SO     Alternative Therapies in Health & Medicine. 5(3):88-91, 1999 May.

PT      Publication Type: Journal Article

DE     Descriptors: *Double-Blind Method; Human; *Research Design; *Single-Blind Method; Support, Non-U.S. Gov't

 

 

AN     1999146724

AU     Strong III FC

TI      The history of the double blind test and the placebo.

IN      F.C. Strong III, State University of Campinas, Campinas, SP; Brazil.

SO     Journal of Pharmacy & Pharmacology. Vol. 51(3)(pp 237-238), 1999.

PT      Publication Type: Journal: Editorial

DE     Descriptors: Placebo; *Double Blind Procedure; Drug Screening; Editorial

 

 

AN     9810062

AU     Dossey L

TI      On double-blinds and double standards: a response to the recent New England Journal editorial.

SO     Alternative Therapies in Health & Medicine. 4(6):18, 20, 1998 Nov.

PT      Publication Type: Journal Article

DE     Descriptors: *Complementary Therapies; *Double-Blind Method; Human; Research/st [Standards]

 

 

AN     9825123

AU     Knipschild PG, Hoerr R, Oschmann R, van Rossum E, van Dongen MC

TI      Optimization of placebos for double-blind clinical trials. Experience with a phytopharmaceutical.

IN      Department of Epidemiology, University of Maastricht, The Netherlands.

SO     Arzneimittel-Forschung. 48(10):1033-6, 1998 Oct.

PT      Publication Type: Clinical Trial; Journal Article; Randomized Controlled Trial

AB     The maintenance of double-blind conditions in placebo-controlled trials depends on the quality of the placebo preparation. The placebo should match the active substance-containing preparation as closely as possible, but it must not contain any substances that might themselves be pharmacologically active. Active substances characterized by a particular colour, taste, smell or other easily perceptible properties constitute a challenge to researchers. The way of developing a placebo that matches a phytopharmaceutical to a satisfactory extent is described and discussed.

DE     Descriptors: Aged; *Central Nervous System Agents/tu [Therapeutic Use]; *Clinical Protocols/st [Standards]; Comparative Study; Dose-Response Relationship, Drug; *Double-Blind Method; *Flavonoids/tu [Therapeutic Use]; Human; *Memory Disorders/dt [Drug Therapy]; Memory Disorders/et [Etiology]; *Placebos; Plant Extracts/tu [Therapeutic Use]; *Randomized Controlled Trials/mt [Methods]; Randomized Controlled Trials/st [Standards]

 

 

AN     9571262

AU     Meinert CL

TI      Masked monitoring in clinical trials--blind stupidity?.

IN      Johns Hopkins University, Baltimore, MD 21205, USA.

SO     New England Journal of Medicine. 338(19):1381-2, 1998 May 7.

PT      Publication Type: Journal Article

DE     Descriptors: Bias (Epidemiology); *Double-Blind Method; Human; *Randomized Controlled Trials/mt [Methods]; Research Design

 

 

AN     9283510

AU     Basoglu M, Marks I, Livanou M, Swinson R

TI      Double-blindness procedures, rater blindness, and ratings of outcome. Observations from a controlled trial.

IN      Department of Psychiatry, University of London, England.

SO     Archives of General Psychiatry. 54(8):744-8, 1997 Aug.

PT      Publication Type: Clinical Trial; Journal Article; Multicenter Study; Randomized Controlled Trial

AB     BACKGROUND: We determined whether blindness in a double-blind randomized controlled trial of alprazolam and exposure therapies in patients with panic disorder and agoraphobia was maintained in assessors and patients, what were the factors related to "unblinding," and whether unblinding was associated with clinical outcome. METHOD: In 129 patients with panic disorder and agoraphobia who were randomized to alprazolam-exposure, placebo-exposure, alprazolam-relaxation, or placebo-relaxation conditions, blindness was tested at the end of treatment by the independent assessors' and patients' classification of the treatment condition. RESULTS: Assessors' classifications were correct in 82% of the alprazolam group and 78% of the placebo group; corresponding figures for patients' classifications were 73% and 70%, respectively. Factors associated with unblinding included drug side effects but not assessors' ratings of treatment outcome. CONCLUSION: Judgment of the validity of the outcome of a randomized controlled trial is easier if the report notes not only the use of a double-blindness procedure but also details how blind the raters remained and how any unblinding affected their ratings of clinical outcome.

DE     Descriptors: Agoraphobia/th [Therapy]; Alprazolam/ae [Adverse Effects]; Alprazolam/tu [Therapeutic Use]; Combined Modality Therapy; *Double-Blind Method; Drug Administration Schedule; Human; Panic Disorder/th [Therapy]; Placebos; *Randomized Controlled Trials/st [Standards]; Relaxation Techniques; Support, Non-U.S. Gov't; Treatment Outcome

 

 

AN     9158270

AU     Ellis SJ, Adams RF

TI      The cult of the double-blind placebo-controlled trial. [Review] [13 refs]

IN      Keele University, Stoke-on-Trent, Staffordshire.

SO     British Journal of Clinical Practice. 51(1):36-9, 1997 Jan-Feb.

PT      Publication Type: Journal Article; Review; Review, Academic

AB     The double-blind, placebo-controlled trial is held as the gold standard in medical knowledge, but this tool of investigation has its weaknesses. These include ethical limitations on the types of comparison that can be undertaken, the central conflict between best practice for an individual and trial protocols, problems of applicability to the general population and applicability of work done on one population to another, type II errors, publication bias, misuse and limitation of statistics, fraud, maintenance of blinding, asking the wrong question, and a simplistic, reductionist view of clinical management. The concentration on the randomised, controlled trial devalues information from other sources, such as natural history studies, clinical experience and case reports. The randomised, controlled trial is an important source of information and as physicians we should welcome more well-crafted trials, but they are not the only source of information. [References: 13]

DE     Descriptors: *Controlled Clinical Trials/st [Standards]; *Double-Blind Method; False Negative Reactions; Fraud; Human; *Publication Bias

 

 

AN     8795875

AU     Kiene H

TI      A critique of the double-blind clinical trial. Part 1. [Review] [41 refs]

IN      Inno Vision Communications, Aliso Viejo, CA 92656, USA.

SO     Alternative Therapies in Health & Medicine. 2(1):74-80, 1996 Jan.

PT      Publication Type: Journal Article; Review; Review, Tutorial

AB     The randomized, double-blind study is generally regarded as the gold standard of clinical drug trials. Bias can occur as a result of the blinding procedure itself, but discussions of this type of bias have been few and far between. This article presents a detailed discussion of such blinding errors, which can obscure genuine drug effects and be of a sufficient magnitude as to generate false-negative results. Uncritical blinding in clinical studies should therefore be questioned. [References: 41]

DE     Descriptors: Bias (Epidemiology); *Double-Blind Method; False Negative Reactions; Human; *Randomized Controlled Trials/st [Standards]

 

 

AN     8795890

AU     Kiene H

TI      A critique of the double-blind clinical trial. Part 2. [Review] [36 refs]

IN      Kritik der klinischen Doppelblindstudie, Munich, Germany.

SO     Alternative Therapies in Health & Medicine. 2(2):59-64, 1996 Mar.

PT      Publication Type: Journal Article; Review; Review, Tutorial

AB     The randomized, double-blind study is generally regarded as the gold standard of clinical drug trials. Bias can occur as a result of the blinding procedure itself, but discussions of this type of bias have been few and far between. This article continues with a detailed discussion of such blinding errors, which can obscure genuine drug effects and be of a sufficient magnitude as to generate false-negative results. Uncritical blinding in clinical studies should therefore be questioned. [References: 36]

DE     Descriptors: *Clinical Trials; *Double-Blind Method; Human; Research

 

 

AN     8889343

AU     Gotzsche PC

TI      Blinding during data analysis and writing of manuscripts.

IN      Nordic Cochrane Centre, Rigshospitalet, Kobenhavn, Denmark.

SO     Controlled Clinical Trials. 17(4):285-90; discussion 290-3, 1996 Aug.

PT      Publication Type: Journal Article

DE     Descriptors: *Bias (Epidemiology); Data Interpretation, Statistical; *Double-Blind Method; Drug Evaluation/mt [Methods]; Drug Evaluation/st [Standards]; Human; *Randomized Controlled Trials/mt [Methods]; Randomized Controlled Trials/st [Standards]; *Research Design

 

 

AN     8889344

AU     Haakenson C, Akiyama T, Hallstrom A, Sather MR

TI      Masking drug treatments in the Cardiac Arrhythmia Pilot Study (CAPS). FASHP for the CAPS Investigators.

IN      VA Cooperative Studies Program.

SO     Controlled Clinical Trials. 17(4):294-303, 1996 Aug.

PT      Publication Type: Clinical Trial; Controlled Clinical Trial; Journal Article; Randomized Controlled Trial

AB     The effectiveness of masking in the Cardiac Arrhythmia Suppression Study (CAPS) was assessed by surveying investigators and study coordinators. CAPS patients were assigned one of five treatments: encainide, flecainide, imipramine, moricizine, or placebo. Had all treatments appeared identical and equal numbers of patients been assigned to each, 20% of guesses of treatment assignment would be correct by chance alone. Since neither was possible in CAPS, higher rates of correct guessing were expected. Overall, respondents correctly identified treatment 39% of the time. Investigators identified the drug 30% of the time with rates of 20%, 24%, 37%, 20%, and 55% for the five treatment groups, respectively, whereas coordinators identified the treatments 47% of the time with scores of 42%, 45%, 50%, 40%, and 60%. Side effects and a suboptimal masking design detracted from masking; electrocardiographic changes did not imipramine, which caused characteristic side effects, was the most frequently identified active treatment. Scores were higher for investigators who had prior experience with the drugs, but scores did not improve over the course of the trial. Findings suggest that to improve masking all drugs should have been matched in appearance or persons evaluating treatments should not have been allowed to see the drugs.

DE     Descriptors: Anti-Arrhythmia Agents/pd [Pharmacology]; *Arrhythmia/dt [Drug Therapy]; Arrhythmia/et [Etiology]; *Bias (Epidemiology); *Clinical Trials/mt [Methods]; *Double-Blind Method; *Drug Evaluation/mt [Methods]; Follow-Up Studies; Human; Myocardial Infarction/co [Complications]; Pilot Projects; Placebos; Research Design; Support, U.S. Gov't, Non-P.H.S.; Support, U.S. Gov't, P.H.S.

 

 

 

AN     1996258705

AU     Boateng F, Sampson A, Schwab B

TI      Statistical analysis of possible bias of clinical judgements due to observing an on-therapy marker variable.

IN      RW Johnson Pharmaceutical Res. Inst.,Raritan, NJ 08869; United States.

SO     Statistics in Medicine. Vol. 15(16)(pp 1747-1755), 1996.

PT      Publication Type: Journal: Article

AB     In certain double-blind clinical trials there is the possibility that certain 'marker variables' observable during the trial may in part unblind the trial, even at a subliminal level. At issue is whether or not this potential unblinding biases the investigators' clinical efficacy assessments. This issue arose after the completion of three clinical trials that compared tretinoin emollient cream (TEC) 0.05 per cent to its vehicle in patients with photodamaged skin, The question raised was whether or not possible 'subliminal unblinding' of the investigators and patients, due to the cutaneous irritation associated with topical tretinoin, might have caused a treatment bias in the study. To address this issue, we undertook a reanalysis of these three clinical trials. In doing so, we develop in this paper a statistical modelling approach to address issues of possible bias introduced by the ability to observe such marker variables. The approach utilizes a linear discriminant analysis to introduce an auxiliary categorical variable for the efficacy analysis. A suitable categorical data model permits the estimation of relevant bias effects. We illustrate this approach with data from the three TEC 0.05 per cent trials.

DE     Descriptors: Retinoic Acid/ae [Adverse Drug Reaction]; Retinoic Acid/ct [Clinical Trial]; Retinoic Acid/dt [Drug Therapy]; *Decision Making; *Double Blind Procedure; Article; Clinical Trial; Controlled Study; Human; Light Damage/dt [Drug Therapy]; Skin Irritation/si [Side Effect]; Statistical Analysis; Statistical Model

 

 

AN     1995304066

AU     Garcia Puig J, Mateos Anton F, Gil Aguado A, Barcina Sanchez C

TI      Can the double blind be known prior to revealing of identification codes? [1]. [Spanish]

IN      Serv. de Medicina Interna, Hospital La Paz, Laboratorios Zeneca Farma S.A.,Madrid; Spain.

SO     Medicina Clinica. Vol. 105(11)(pp 437-438), 1995.

PT      Publication Type: Journal: Letter

DE     Descriptors: *Lisinopril/dt [Drug Therapy]; *Lisinopril/ct [Clinical Trial]; *Nifedipine/dt [Drug Therapy]; *Nifedipine/ct [Clinical Trial]; *Double Blind Procedure; *Drug Identification; Clinical Trial; Controlled Study; Diabetes Mellitus; Human; Hypertension/dt [Drug Therapy]; Letter; Major Clinical Study; Microalbuminuria; Multicenter Study

 

 

AN     7618021

AU     Morin CM, Colecchi C, Brink D, Astruc M, Mercer J, Remsberg S

TI      How "blind" are double-blind placebo-controlled trials of benzodiazepine hypnotics?.

IN      Medical College of Virginia/Virginia Commonwealth University, Richmond, USA.

SO     Sleep. 18(4):240-5, 1995 May.

PT      Publication Type: Clinical Trial; Journal Article; Randomized Controlled Trial

AB     This study examined the accuracy of insomnia patients and their treating physicians in rating whether an active hypnotic drug or a placebo was given in treatment. Forty older adults with primary insomnia were randomly assigned to either an active (temazepam) or a placebo condition using a double-blind strategy. Ratings of treatment conditions were obtained at 1 week (early treatment), 4 weeks (midtreatment), and 8 weeks (late treatment). Patients were able to accurately discriminate (beyond chance levels) between the active and placebo medications at the early (76.9% accuracy) and late treatment assessment timepoints (78.1% accuracy), but not at midtreatment (51.5% accuracy). Therapists, however, were able to make accurate discriminations at the late treatment assessment timepoint only (80% accuracy); early (69.2% accuracy) and midtreatment (47.2% accuracy) ratings did not exceed chance levels. Patients who had used hypnotic drugs prior to this trial were more accurate in their judgments of treatment conditions than those without prior exposure. The findings raise an important issue about the internal validity of the double-blind strategy, which may in fact be only a single-blind procedure.

DE     Descriptors: Aged; Benzodiazepines/ae [Adverse Effects]; *Benzodiazepines/tu [Therapeutic Use]; *Double-Blind Method; Female; Human; Male; Middle Aged; Perception; *Randomized Controlled Trials; *Sleep Initiation and Maintenance Disorders/dt [Drug Therapy]; Support, U.S. Gov't, P.H.S.; Treatment Outcome

 

 

AN     8552900

AU     Shih WJ, Gould AL

TI      Re-evaluating design specifications of longitudinal clinical trials without unblinding when the key response is rate of change.

IN      Merck Research Laboratories, Rahway, New Jersey 07065-914, USA.

SO     Statistics in Medicine. 14(20):2239-48, 1995 Oct 30.

PT      Publication Type: Journal Article

AB     The design of clinical trials often requires knowledge of quantities such as between- and within subject variances about which only imprecise information exists. To provide assurance that the study has the desired power to detect a minimum clinically meaningful difference between treatment groups. Gould, Gould and Shih, and Shih have recommended obtaining relevant information from the trial at an interim stage without unblinding. Wittes and Brittain provided a similar recommendation, but viewed the portion up to the interim stage as an (internal) pilot study and required unblinding. This paper considers the problem of re-evaluating the design specifications in longitudinal clinical trials when the key response is the rate of change (slope). The proposed method aims to re-evaluate the sample size and study duration in a way that maintains the trial's blinding, using an EM algorithm. Simulation results show that the effect on type I error rate in negligible, but the potential gain in power can be substantial. The procedure is simple to use in practice, as it does not unblind patients' treatment identifications, and, since it does not unveil the relative efficacy of treatments, it fulfils the requirement of a valid 'administrative' (interim) analysis.

DE     Descriptors: Algorithms; Analysis of Variance; Computer Simulation; *Double-Blind Method; Human; *Longitudinal Studies; *Randomized Controlled Trials/mt [Methods]; Reproducibility of Results; Sample Size; *Single-Blind Method; Time Factors

 

 

AN     8135885

AU     Hogel J, Walach H, Gaus W

TI      Change-to-Open-Label Design. Proposal and discussion of a new design for clinical parallel-group double-masked trials.

IN      Universitat Ulm, Klinische Dokumentation, Fed. Rep. of Germany.

SO     Arzneimittel-Forschung. 44(1):97-9, 1994 Jan.

PT      Publication Type: Journal Article

AB     The "Change-to-Open-Label Design" (COLA-design) is proposed to overcome some of the ethical and organizational problems of the usual double-masked design in certain situations while preserving its scientific rigor. Patients are randomized on a doubled-masked basis into treatment groups. During the trial the patient or the treating physician may ask for a change from the masked treatment to any open-label treatment of their choice (experimental or not), if the masked treatment is thought to be unsatisfactory. It seems to be easier to obtain a patient's informed consent to participate in placebo controlled double-masked trials especially for long term studies. The main outcome variable in COLA-design is the time until a patient demands for such a change. "Survival analysis" is a powerful statistical method to evaluate this outcome variable. Even patients lost from observation can be included in the evaluation: they still deliver censored outcome values. Evidently, in trials with a COLA-design the patient's personal impression of the therapy is the most important factor in its assessment. Therapeutical success is mingled with undesirable effects into the outcome measure; therefore this design is especially applicable to investigate treatments supposed to increase quality of life.

DE     Descriptors: *Double-Blind Method; Drug Therapy/ae [Adverse Effects]; Human; Patient Satisfaction; Physicians; Quality Control; *Randomized Controlled Trials; *Research Design

 

 

AN     7906321

AU     Anonymous

TI      Blinded by science.[see comment][comment].

SO     Lancet. 343(8897):553-4, 1994 Mar 5.

CM     Comment in: Lancet. 1994 Apr 23;343(8904):1040; PMID: 7909070, Comment on: Lancet. 1994 Mar 5;343(8897):568-71; PMID: 7906329

PT      Publication Type: Comment; Editorial

DE     Descriptors: Aged; *Beds; Control Groups; *Decubitus Ulcer/pc [Prevention & Control]; *Double-Blind Method; Human; Randomized Controlled Trials; Research Subjects

 

 

AN     7968033

AU     Kleijnen J, de Craen AJ, van Everdingen J, Krol L

TI      Placebo effect in double-blind clinical trials: a review of interactions with medications. [Review] [18 refs]

IN      Department of Clinical Epidemiology and Biostatistics, University of Amsterdam, Netherlands.

SO     Lancet. 344(8933):1347-9, 1994 Nov 12.

PT      Publication Type: Journal Article; Review; Review, Academic

DE     Descriptors: *Double-Blind Method; Human; Informed Consent; *Placebo Effect; *Randomized Controlled Trials

 

 

AN     8290055

AU     Noseworthy JH, Ebers GC, Vandervoort MK, Farquhar RE, Yetisir E, Roberts R

TI      The impact of blinding on the results of a randomized, placebo-controlled multiple sclerosis clinical trial.

IN      Department of Neurology, Mayo Clinic and Foundation, Rochester, MN 55905.

SO     Neurology. 44(1):16-20, 1994 Jan.

PT      Publication Type: Clinical Trial; Journal Article; Randomized Controlled Trial

AB     In the randomized, placebo-controlled, physician-blinded Canadian cooperative trial of cyclophosphamide and plasma exchange, neither active treatment regimens (group I: i.v. cyclophosphamide and prednisone; group II: weekly plasma exchange, oral cyclophosphamide, and prednisone) were superior to placebo (group III: sham plasma exchange and placebo medications) using the blinded, evaluating neurologists' assessments of disease course (primary analysis). All patients were examined by both a blinded and an unblinded neurologist at each assessment in this trial. We compared the blinded and unblinded neurologists' judgment of treatment response and analyzed the clinical behavior of patients who correctly guessed their treatment. The unblinded (but not the blinded) neurologists' scores demonstrated an apparent treatment benefit at 6, 12, and 24 months for the group II patients (not group I or placebo; p < 0.05, two-tailed). There were no significant differences in the time to treatment failure or in the proportions of patients improved, stable, or worse between the group II and group III patients who correctly guessed their treatment assignments and those who did not. Physician blinding prevented an erroneous conclusion about treatment efficacy (false positive, type 1 error).

DE     Descriptors: Comparative Study; Cyclophosphamide/tu [Therapeutic Use]; *Double-Blind Method; Human; *Multiple Sclerosis/th [Therapy]; *Physicians; Placebos; Plasma Exchange; Prednisone/tu [Therapeutic Use]; *Single-Blind Method; Support, Non-U.S. Gov't

 

 

AN     8501455

AU     Fisher S, Greenberg RP

TI      How sound is the double-blind design for evaluating psychotropic drugs?. [Review] [42 refs]

IN      Department of Psychiatry, State University of New York Health Science Center, Syracuse 13210.

SO     Journal of Nervous & Mental Disease. 181(6):345-50, 1993 Jun.

PT      Publication Type: Journal Article; Review; Review, Tutorial

AB     Sufficient data have accumulated to raise serious doubts about the integrity of the double-blind design that is presumed to shield psychotropic drug trials from bias and expectations. A major deficit in most drug trials has been the use of inert rather than active placebos. The deficiencies of the double-blind paradigm call for a questioning stance with respect to previous studies of psychotropic drug efficacy. Various possible ways of strengthening the double-blind paradigm are reviewed. [References: 42]

DE     Descriptors: *Clinical Trials/st [Standards]; *Double-Blind Method; Human; Placebos; *Psychotropic Drugs/tu [Therapeutic Use]

 

 

AN     7870914

AU     Kirsch I, Rosadino MJ

TI      Do double-blind studies with informed consent yield externally valid results? An empirical test.

IN      Department of Psychology, University of Connecticut, Storrs 06269-1020.

SO     Psychopharmacology. 110(4):437-42, 1993.

PT      Publication Type: Clinical Trial; Journal Article; Randomized Controlled Trial

AB     Subjective and physiological effects of caffeine were investigated via a 3 x 2 x 3 design that assessed independent and interactive effects of instructions (told caffeine versus told no caffeine versus not told whether beverage contained caffeine), actual beverage content (caffeine versus no caffeine), and time after ingestion (15, 30, and 45 min). Instructions affected alertness at 15 min after ingestion. Caffeine increased alertness at 30 min after ingestion and systolic blood pressure at 30 min and 45 min after ingestion. A highly significant instruction by drug interaction on tension was obtained at all measurement points, indicating an increase in tension only among subjects who knowingly received caffeine. Because people are generally informed of drug content in non-research settings, these data challenge the external validity of typical double-blind studies, in which subjects are informed of the possibility of receiving a placebo as part of the consent procedure.

DE     Descriptors: Adolescent; Adult; *Affect/de [Drug Effects]; Attention/de [Drug Effects]; Blood Pressure/de [Drug Effects]; *Caffeine/pd [Pharmacology]; *Clinical Trials/mt [Methods]; *Double-Blind Method; Female; Human; *Informed Consent; Male; Placebos; Pulse/de [Drug Effects]

 

 

AN     1443253

AU     White K, Kando J, Park T, Waternaux C, Brown WA

TI      Side effects and the "blindability" of clinical drug trials.[see comment].

IN      Department of Psychiatry, Providence VA Medical Center, RI 02908.

SO     American Journal of Psychiatry. 149(12):1730-1, 1992 Dec.

CM     Comment in: Am J Psychiatry. 1993 Nov;150(11):1759-60; author reply 1760-1; PMID: 8214202, Comment in: Am J Psychiatry. 1993 Nov;150(11):1760; author reply 1760-1; PMID: 8214203

PT      Publication Type: Journal Article; Multicenter Study

AB     A novel, simple approach to retrospective assessment of "blindability" was applied to data on outpatients in a controlled, double-blind clinical comparison of a putative antidepressant, etoperidone, and placebo. A "blind" evaluator proved capable of discriminating between the active drug and placebo on the basis of reported side effects alone, raising questions about the true blindness of the study.

DE     Descriptors: Ambulatory Care; *Antidepressive Agents/ae [Adverse Effects]; Antidepressive Agents/tu [Therapeutic Use]; Bias (Epidemiology); *Clinical Trials/st [Standards]; Depressive Disorder/dt [Drug Therapy]; *Double-Blind Method; Human; Placebos; Retrospective Studies; Support, Non-U.S. Gov't; Trazodone/ae [Adverse Effects]; *Trazodone/aa [Analogs & Derivatives]; Trazodone/tu [Therapeutic Use]

 

 

AN     1490788

AU     Fischer W, Haase W, Ruther E, Clarenbach P, Hajak G

TI      Problems in performing a double-blind multicenter study using a hypnotic in private practice.

IN      Rhone-Poulenc Rorer GmbH, Cologne, Germany.

SO     International Journal of Clinical Pharmacology, Therapy, & Toxicology. 30(11):474, 1992 Nov.

PT      Publication Type: Journal Article

AB     1. The procedure described--the immediate data transfer and entry system (ITES)--is suitable to improve the quality of data collected in multicentre studies in private practice. 2. The results of the study show that regarding influence on sleep quality and daytime well-being the non-benzodiazepine Z is significantly superior to placebo and slightly superior to the benzodiazepines F and T. 3. The advantage of Z treatment is the better daytime well-being after taking the hypnotic for sleep induction the night before. 4. This study shows that a quality standard equal to that in clinical practice may be achieved in private practice.

DE     Descriptors: Adolescent; Adult; Aged; *Double-Blind Method; *Family Practice; Female; Human; Hypnotics and Sedatives/ae [Adverse Effects]; *Hypnotics and Sedatives/tu [Therapeutic Use]; Male; Middle Aged; *Multicenter Studies; *Randomized Controlled Trials; *Sleep Disorders/dt [Drug Therapy]; Sleep Disorders/px [Psychology]

 

 

AN     1353838

AU     Sacristan JA, Soto J, Alanis A

TI      Complacency bias in clinical trials.

SO     Lancet. 340(8815):375, 1992 Aug 8.

PT      Publication Type: Letter

DE     Descriptors: *Bias (Epidemiology); *Clinical Trials/st [Standards]; *Double-Blind Method; Human; *Motivation; *Research Personnel/px [Psychology]

 

 

AN     1793642

AU     Charlton BG

TI      Medical practice and the double-blind, randomized controlled trial.[see comment].

SO     British Journal of General Practice. 41(350):355-6, 1991 Sep.

CM     Comment in: Br J Gen Pract. 1991 Dec;41(353):520; PMID: 1807334

PT      Publication Type: Editorial

DE     Descriptors: *Clinical Medicine; *Double-Blind Method; Human; Physician's Role; Randomized Controlled Trials

 

 

AN     2054578

AU     Double D

TI      Blinding trials.[see comment][comment].

SO     British Journal of Psychiatry. 158:573-4, 1991 Apr.

CM     Comment in: Br J Psychiatry. 1991 Jul;159:159-60; PMID: 1888966, Comment on: Br J Psychiatry. 1990 Aug;157:300; PMID: 2224388, Comment on: Br J Psychiatry. 1990 Dec;157:934-5; PMID: 2136594

PT      Publication Type: Comment; Letter

DE     Descriptors: *Antidepressive Agents/tu [Therapeutic Use]; *Clinical Trials; *Depressive Disorder/dt [Drug Therapy]; Depressive Disorder/px [Psychology]; *Double-Blind Method; Human

 

 

AN     1888966

AU     Newcombe R

TI      Double blind acceptance.[comment].

SO     British Journal of Psychiatry. 159:159-60, 1991 Jul.

CM     Comment on: Br J Psychiatry. 1991 Apr;158:573-4; PMID: 2054578

PT      Publication Type: Comment; Letter

DE     Descriptors: Bias (Epidemiology); *Double-Blind Method; Human; Random Allocation; Research Design/st [Standards]

 

 

AN     2002136

AU     Margraf J, Ehlers A, Roth WT, Clark DB, Sheikh J, Agras WS, Taylor CB

TI      How "blind" are double-blind studies?.

IN      Philipps-University Marburg, Federal Republic of Germany.

SO     Journal of Consulting & Clinical Psychology. 59(1):184-7, 1991 Feb.

PT      Publication Type: Clinical Trial; Journal Article; Randomized Controlled Trial

AB     Psychopharmacological studies usually attempt to eliminate "nonspecific" influences on outcome by double-blind designs. In a randomized, double-blind comparison of alprazolam, imipramine, and placebo, the great majority of panic disorder patients (N = 59) and their physicians were able to rate accurately whether active drug or placebo had been given. Moreover, physicians could distinguish between the two types of active drugs. Inasmuch as correct rating was possible halfway through treatment, concerns about the internal validity of the double-blind strategy arise.

DE     Descriptors: Adult; Alprazolam/tu [Therapeutic Use]; Anxiety Disorders/di [Diagnosis]; Anxiety Disorders/dt [Drug Therapy]; *Double-Blind Method; Female; Human; Imipramine/tu [Therapeutic Use]; Male; Middle Aged; Panic; Placebos; Psychotherapy; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

 

 

AN     2180531

AU     Newcombe RG

TI      Double-blind trials.[see comment][comment].

SO     British Journal of Psychiatry. 156:282, 1990 Feb.

CM     Comment in: Br J Psychiatry. 1990 Aug;157:300; PMID: 2224388, Comment on: Br J Psychiatry. 1989 Nov;155:700-1; PMID: 2611601

PT      Publication Type: Clinical Trial; Comment; Letter

DE     Descriptors: Clinical Trials; *Double-Blind Method; Human

 

 

AN     2224388

AU     Double DB

TI      Limitations of double-blind trials.[see comment][comment].

SO     British Journal of Psychiatry. 157:300, 1990 Aug.

CM     Comment in: Br J Psychiatry. 1990 Dec;157:934-5; PMID: 2136594, Comment in: Br J Psychiatry. 1991 Apr;158:573-4; PMID: 2054578, Comment on: Br J Psychiatry. 1990 Feb;156:282; PMID: 2180531

PT      Publication Type: Comment; Letter

DE     Descriptors: Bias (Epidemiology); *Clinical Trials/mt [Methods]; *Double-Blind Method; Human; *Mental Disorders/dt [Drug Therapy]; *Randomized Controlled Trials/mt [Methods]

 

 

AN     2136594

AU     Newcombe RG

TI      Limitations of double-blind trials.[see comment][comment].

SO     British Journal of Psychiatry. 157:934-5, 1990 Dec.

CM     Comment in: Br J Psychiatry. 1991 Apr;158:573-4; PMID: 2054578, Comment on: Br J Psychiatry. 1990 Aug;157:300; PMID: 2224388

PT      Publication Type: Comment; Letter

DE     Descriptors: *Double-Blind Method; Human; *Psychotropic Drugs/tu [Therapeutic Use]; *Randomized Controlled Trials

 

 

AN     2611601

AU     Oxtoby A, Jones A, Robinson M

TI      Is your 'double-blind' design truly double-blind?[see comment].

IN      Whiston Hospital, Prescot, Merseyside.

SO     British Journal of Psychiatry. 155:700-1, 1989 Nov.

CM     Comment in: Br J Psychiatry. 1990 Feb;156:282; PMID: 2180531, Comment in: Br J Psychiatry. 1990 Jul;157:151-2; PMID: 2397355

PT      Publication Type: Journal Article

DE     Descriptors: *Clinical Trials/st [Standards]; *Double-Blind Method; Human; Periodicals/st [Standards]; Research Design/st [Standards]

 

 

AN     2805022

AU     Bell DS

TI      Topics in clinical research. III. The importance of randomized, double-blind procedures in clinical trials.

IN      Division of Endocrinology and Metabolism, University of Alabama, Birmingham.

SO     Clinical Therapeutics. 11(5):565-7, 1989 Sep-Oct.

PT      Publication Type: Journal Article

DE     Descriptors: *Double-Blind Method; *Pharmacology, Clinical/td [Trends]; Placebos; *Randomized Controlled Trials; Research Design

RN     CAS Registry number: 0 (Placebos)

 

 

AN     2909265

AU     Ney PG

TI      Double-blinding in clinical trials.

SO     CMAJ Canadian Medical Association Journal. 140(1):15, 1989 Jan 1.

PT      Publication Type: Letter

DE     Descriptors: *Clinical Trials/mt [Methods]; Clinical Trials/st [Standards]; *Double-Blind Method/st [Standards]; *Drug Evaluation/st [Standards]; Human; *Research Design/st [Standards]

 

 

AN     2723134

AU     Munjack DJ, Brown RA, McDowell D, Palmer R

TI      Actual medication versus therapist guesses: in a blind study, how blind is blind?.

SO     Journal of Clinical Psychopharmacology. 9(2):148-9, 1989 Apr.

PT      Publication Type: Letter

DE     Descriptors: *Clinical Trials; *Double-Blind Method; Human; Mental Disorders/dt [Drug Therapy]; Mental Disorders/px [Psychology]; *Research Design

 

 

AN     2668682

AU     Allen AD

TI      Making moral decisions on a double-blinded drug trial in progress without breaking the code: a primer on posterior analysis.

IN      Biomedical Sciences Division, Algorithms, Inc., Northridge, CA 91325.

SO     Medical Decision Making. 9(3):207-16, 1989 Jul-Sep.

PT      Publication Type: Journal Article

AB     The double blinding of drug trials to prevent bias deprives physicians of information they need in order to comply with their duty to treat patients and do them no harm. This ethical dilemma can be ameliorated with a standard statistical method known as posterior analysis. The clinical researcher can use posterior analysis to calculate the probability that a patient in a double-blinded drug trial is in the placebo group, based on the patient's clinical status. The clinician can also calculate the probability that the drug is safe and efficacious, as compared with the placebo, without breaking the code.

DE     Descriptors: *Clinical Trials; *Decision Support Techniques; *Double-Blind Method; *Ethics, Medical; Government Regulation; Human; Nontherapeutic Human Experimentation; Placebos; Probability; Random Allocation; *Research Design/st [Standards]; Research Subjects; Risk Assessment

 

 

AN     3365327

AU     Kirsch I, Weixel LJ

TI      Double-blind versus deceptive administration of a placebo.

IN      University of Connecticut, Department of Psychology, Storrs 06268.

SO     Behavioral Neuroscience. 102(2):319-23, 1988 Apr.

PT      Publication Type: Clinical Trial; Controlled Clinical Trial; Journal Article

AB     Subjects were given varying doses of a placebo, consisting of decaffeinated coffee, with double-blind or deceptive instructions. Deceptive administration simulated clinical situations in that subjects were led to believe that they were receiving an active drug. In contrast, subjects in double-blind conditions were aware that they might receive a placebo. Double-blind and deceptive administration of the placebo produced different, and in some instances, opposite effects on pulse rate, systolic blood pressure, and subjective mood. Deceptive administration produced an increase in pulse rate, whereas double-blind administration did not. A theoretically predicted curvilinear effect on systolic blood pressure, alertness, tension, and certainty of having consumed caffeine was confirmed with deceptive administration, but not with double-blind administration. Double-blind administration produced curves in the opposite direction on each of these variables. The effects of the placebo on motor performance varied as a function of subject's beliefs about the effects of caffeine. These data challenge the validity of double-blind experimental designs and suggest that this common method of drug assessment may lead to spurious conclusions.

DE     Descriptors: Adolescent; Adult; *Clinical Trials/mt [Methods]; *Double-Blind Method; Female; Human; Male; Patient Participation; *Placebos; *Research Design

 

 

AN     3816016

AU     Moscucci M, Byrne L, Weintraub M, Cox C

TI      Blinding, unblinding, and the placebo effect: an analysis of patients' guesses of treatment assignment in a double-blind clinical trial.

SO     Clinical Pharmacology & Therapeutics. 41(3):259-65, 1987 Mar.

PT      Publication Type: Journal Article

AB     We administered a questionnaire to assess maintenance of patients' blindness at the end of a double-blind clinical trial of Osmotic Release Oral System phenylpropanolamine (PPA) vs. placebo in mild obesity. Seventy-four percent of placebo participants and 43% of PPA participants guessed their treatment correctly. Appetite control was the most frequently reported basis for guessing PPA, even by placebo participants. Lack of adverse drug reactions was the most frequently reported basis for guessing placebo, even by PPA participants. Participants receiving either PPA or placebo and guessing PPA lost more weight, had less diet difficulty, and had more adverse drug reactions than had participants receiving either PPA or placebo and guessing placebo. Although blindness was probably maintained in the PPA group, the placebo group seems to have been, at least at the study's end, unblinded. These results suggest that in double-blind studies, differences in outcome or incidence of adverse drug reactions may act as unblinding factors.

DE     Descriptors: Body Weight/de [Drug Effects]; *Clinical Trials; Delayed-Action Preparations; Diet, Reducing; *Double-Blind Method; Human; Obesity/dt [Drug Therapy]; Phenylpropanolamine/ae [Adverse Effects]; Phenylpropanolamine/tu [Therapeutic Use]; *Placebos; Questionnaires; Random Allocation; *Research Design; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

 

 

AN     3641026

AU     Ney PG, Collins C, Spensor C

TI      Double blind: double talk or are there ways to do better research.

SO     Medical Hypotheses. 21(2):119-26, 1986 Oct.

PT      Publication Type: Journal Article

AB     In an attempt to counteract placebo effects, scientists studying the effectiveness of medication often use the 'double blind' trial. Unfortunately, in less than 5% of the studies reported in major medical and psychiatric journals was there a check to determine whether patients and observers were blind. Between 1972 and 1983 there was increasing reliance on active placebos which attempt to mimic the effects of the medication. It is unlikely however, that patients are not aware of significantly different physiologic changes within them resulting from the different chemicals. Whenever a physician informs a subject that they may be on placebo or active treatment medication, they will spend much time in trying to guess when they are taking which. In these situations Philip's paradox will apply. This states that the more potent a therapeutic variable the less likely its efficacy can be 'proven' in a double-blind study. One can only 'prove' that medication is no more effective than placebo. To have a truly blind procedure, the active placebo must have identical physiological effects to those of the medication being studied. We are now using the patient's and the observer's awareness of changes as useful information to obtain: a guess factor, the percentage of correct guesses whether the patient is on medication or placebo; a direction factor, whether the patient considers the change beneficial or detrimental; an attributional factor, whether the change is considered to result from medication or other intervening variables. This information is usually reliable and can be analyzed with the usual statistical procedures.

DE     Descriptors: Attitude to Health; Awareness; *Double-Blind Method; Ethics, Medical; Human; Patients/px [Psychology]; Physicians/px [Psychology]; *Placebos; *Research Design

 

 

AN     3538107

AU     Rabkin JG, Markowitz JS, Stewart J, McGrath P, Harrison W, Quitkin FM, Klein DF

TI      How blind is blind? Assessment of patient and doctor medication guesses in a placebo-controlled trial of imipramine and phenelzine.

SO     Psychiatry Research. 19(1):75-86, 1986 Sep.

PT      Publication Type: Clinical Trial; Journal Article; Randomized Controlled Trial

AB     The purpose of the double blind is to protect the internal validity of a clinical trial by preventing knowledge of treatment conditions from influencing outcome or its assessment. We studied medication guesses of 137 depressed patients and/or their doctors at the end of a 6-week randomized trial of placebo, imipramine, and phenelzine. Overall, 78% of the patients and 87% of the doctors correctly distinguished between placebo and active medication. Clinical outcome, treatment condition, and their interaction each contributed to guessing accuracy, while medication experience and side effects assessed only in week 6 did not. Accuracy was high, however, even when cases were stratified for clinical outcome, indicating that other cues were available to the patients and doctors. These may include patterns and timing of side effects and clinical response not detectable in this end-point analysis.

DE     Descriptors: Adolescent; Adult; Clinical Trials; Comparative Study; Cues; *Depressive Disorder/dt [Drug Therapy]; *Double-Blind Method/st [Standards]; Human; Imipramine/ae [Adverse Effects]; *Imipramine/tu [Therapeutic Use]; Middle Aged; Patients/px [Psychology]; Phenelzine/ae [Adverse Effects]; *Phenelzine/tu [Therapeutic Use]; Physicians/px [Psychology]; Random Allocation; *Research Design/st [Standards]; Support, U.S. Gov't, P.H.S.

 

 

AN     4074613

AU     Jones AL, Grainger SL, Smith SE

TI      The elimination of treatment predictability in double-blind studies.

SO     British Journal of Clinical Pharmacology. 20(4):428-9, 1985 Oct.

PT      Publication Type: Journal Article

DE     Descriptors: *Double-Blind Method; Human; Pharmaceutical Preparations/ae [Adverse Effects]; Placebos; *Research Design

 

 

AN     1985112015

AU     Buckalew LW

TI      Methodological issues in drug assessment research.

IN      Aerospace Medical Research Branch, USAF School of Aerospace Medicine, Brooks AFB, TX; United States.

SO     Drug Development Research. Vol. 5(2)(pp 103-110), 1985.

PT      Publication Type: Journal

AB     Increased sensitivity to methodological issues in drug assessment research is needed in light of challenges to research design, conduct, and outcomes. Major issues presented include (a) the nature and adequacy of placebo controls, (b) problems in maintaining the integrity of 'blind' conditions, and (c) the potential design-compromising effects of informed consent. The necessity of true matching placebos, particularly concerning physical/perceptual characteristics and the ability to produce transitory changes in subjects, was stressed. Though the double-blind condition has conceptual integrity, the operation of drug and placebo side effects and associated guess bias may confound research results. Use of a triple-blind condition and addition of a drug-disguised group is suggested. Last, the issue of informed consent and its implications for the integrity of drug research is a problem deserving more attention.

DE     Descriptors: *Placebo; *Control System; *Double Blind Procedure; *Drug Determination; *Drug Efficacy; *Drug Therapy; Priority Journal; Therapy; Review; Human; Psychological Aspect; Controlled Study

 

 

AN     3974051

AU     Byington RP, Curb JD, Mattson ME

TI      Assessment of double-blindness at the conclusion of the beta-Blocker Heart Attack Trial.

SO     JAMA. 253(12):1733-6, 1985 Mar 22-29.

PT      Publication Type: Clinical Trial; Journal Article; Randomized Controlled Trial

AB     At the conclusion of a double-blinded, randomized clinical trial of propranolol hydrochloride, but before unblinding, the patients and clinic personnel were asked to guess the treatment group assignment of each patient. While 79.9% of the patients receiving propranolol correctly identified their treatment group assignment, 57.2% of the patients receiving placebo incorrectly guessed that they were also in the propranolol group. No specific mechanism was identified to explain why more patients receiving propranolol were better able to guess their group assignment. Clinic physicians correctly identified the group assignment of 69.9% of the patients receiving propranolol and 68.8% of the patients receiving placebo. Clinic coordinators correctly identified the group assignment of 67.1% of the patients receiving propranolol and 70.6% of the patients receiving placebo. For clinic personnel, heart rate level and heart rate change seem to be the mechanisms employed to identify their patients' treatment assignment.

DE     Descriptors: Adult; Aged; *Clinical Trials/mt [Methods]; Control Groups; *Double-Blind Method/st [Standards]; Female; Heart Rate/de [Drug Effects]; Human; Male; Middle Aged; *Myocardial Infarction/dt [Drug Therapy]; *Propranolol/tu [Therapeutic Use]; Random Allocation; *Research Design/st [Standards]; Socioeconomic Factors; Support, U.S. Gov't, P.H.S.

 

 

AN     2861298

AU     Spodick DH

TI      Double-blind as a BHAT.

SO     JAMA. 254(6):755, 1985 Aug 9.

PT      Publication Type: Letter

DE     Descriptors: *Adrenergic beta-Antagonists/tu [Therapeutic Use]; *Double-Blind Method; Human; *Myocardial Infarction/dt [Drug Therapy]; *Research Design

 

 

AN     3998203

AU     Hughes JR, Krahn D

TI      Blindness and the validity of the double-blind procedure.

SO     Journal of Clinical Psychopharmacology. 5(3):138-42, 1985 Jun.

PT      Publication Type: Clinical Trial; Journal Article; Randomized Controlled Trial

AB     This article describes a method for assessing whether the blindness of a double-blind study is maintained and, if not, whether failure to maintain blindness could have invalidated the results of the study. The benefit of using the method is illustrated in a study of the effect of nicotine gum on the tobacco withdrawal syndrome. In that study, many subjects were able to identify which drug they received; however, a drug effect was present among subjects who correctly identified their drug, among subjects who incorrectly identified their drug, and among subjects who could not tell which drug they received. Thus, failure to maintain blindness could not have invalidated the results of the study. The authors believe double-blind studies should routinely assess blindness, and they recommend their method as a simple and easy way to assess blindness.

DE     Descriptors: Chewing Gum; *Double-Blind Method/st [Standards]; Human; Nicotine/ad [Administration & Dosage]; Random Allocation; *Research Design/st [Standards]; Smoking/pc [Prevention & Control]; Substance Withdrawal Syndrome/dt [Drug Therapy]; Support, Non-U.S. Gov't

 

 

AN     6468216

AU     Bonfils S, Baron JH, Blum A

TI      Uncontrolled factors in controlled trials of peptic ulcer.

SO     Digestive Diseases & Sciences. 29(9):858-61, 1984 Sep.

PT      Publication Type: Journal Article

DE     Descriptors: *Anti-Ulcer Agents/tu [Therapeutic Use]; *Clinical Trials/mt [Methods]; *Double-Blind Method; Human; Patients/px [Psychology]; Peptic Ulcer/dt [Drug Therapy]; Physician-Patient Relations; Placebos; *Research Design

 

 

AN     6846655

AU     Barsa JA

TI      More on the fallibility of the double-blind.

SO     American Journal of Psychiatry. 140(6):820-1, 1983 Jun.

PT      Publication Type: Letter

DE     Descriptors: *Double-Blind Method/st [Standards]; Human; Informed Consent; Psychiatry; *Research Design/st [Standards]

 

 

AN     6753613

AU     Brownell KD, Stunkard AJ

TI      The double-blind in danger: untoward consequences of informed consent.

SO     American Journal of Psychiatry. 139(11):1487-9, 1982 Nov.

PT      Publication Type: Clinical Trial; Journal Article

AB     Patients and physicians correctly identified medication assignments in 70% of the cases in a double-blind trial of an appetite suppressant. The breach of the double-blind design may have had therapeutic consequences; correct identification was associated with favorable outcome. These findings suggest that requirements for describing the side effects of medications to patients before they give informed consent may help them guess which medication they receive and thus may influence the integrity of double-blind studies and the results of controLled trials.

DE     Descriptors: Adult; Aged; Body Weight; Clinical Trials; Dizziness/ci [Chemically Induced]; *Double-Blind Method/st [Standards]; Fatigue/ci [Chemically Induced]; Female; Fenfluramine/ae [Adverse Effects]; Human; *Informed Consent; Middle Aged; Placebos; *Research Design/st [Standards]; Risk Assessment; Support, U.S. Gov't, P.H.S.; Xerostomia/ci [Chemically Induced]

 

 

AN     7127995

AU     Howard J, Whittemore AS, Hoover JJ, Panos M

TI      How blind was the patient blind in AMIS?.

SO     Clinical Pharmacology & Therapeutics. 32(5):543-53, 1982 Nov.

PT      Publication Type: Journal Article

AB     The Aspirin Myocardial Infarction Study (AMIS) was a double-blind placebo-controlled trial to test the effect of aspirin on the survival of 4524 people who had experienced a prior heart attack. Shortly before their closeout visits, 400 of the participants were randomly selected to be interviewed concerning their perceptions of their treatment assignments; 380 were actually interviewed. A bare majority (52)% correctly identified their study therapy, 28% mistakenly named the alternative treatment, 13% declined to guess, and 7% specified extraneous substances. According to the proposed formula for evaluating the patient blind, only 24% of the sample made "informed" guesses regarding their therapy, while the remainder guessed in an uninformed way or not at all. Those who tested their capsules (usually be taste) showed proportionately more correct responses than the nontesters. Correctness also varied with the reasons for the subjects' guesses (e.g., side effects). Among the sample as a whole, most people were only moderately or less than moderately certain their guess was correct. Even among those who were in fact correct, only 18% were absolutely certain of their choice.

DE     Descriptors: Adult; Aged; Aspirin/tu [Therapeutic Use]; *Double-Blind Method; Female; Human; Male; Middle Aged; Myocardial Infarction/dt [Drug Therapy]; Perception; *Placebos; Random Allocation; *Research Design; Support, U.S. Gov't, P.H.S.

 

 

AN     7160189

AU     Halperin M, Lan KK, Ware JH, Johnson NJ, DeMets DL

TI      An aid to data monitoring in long-term clinical trials.

SO     Controlled Clinical Trials. 3(4):311-23, 1982 Dec.

PT      Publication Type: Journal Article

DE     Descriptors: *Clinical Trials/st [Standards]; *Double-Blind Method; Human; Mortality; *Research Design; *Statistics; Support, U.S. Gov't, P.H.S.; Time Factors

 

 

AN     6789934

AU     Gore SM

TI      Assessing clinical trials- double-blind trials.

SO     British Medical Journal Clinical Research Ed.. 283(6284):122-4, 1981 Jul 11.

PT      Publication Type: Journal Article

DE     Descriptors: Attitude of Health Personnel; *Clinical Trials/mt [Methods]; *Double-Blind Method; *Research Design; Statistics

 

 

AN     6105316

AU     Friedman L, Passamani E, May G, Furberg C, Friedewald W

TI      Placebo controlled double blind trials.

SO     Lancet. 2(8186):147-8, 1980 Jul 19.

PT      Publication Type: Letter

DE     Descriptors: *Clinical Trials; *Double-Blind Method; Drug Administration Schedule; *Drug Therapy; Human; Placebos; *Research Design

 

 

AN     618704

AU     Zifferblatt SM, Wilbur CS

TI      A psychological perspective for double-blind trials.

SO     Clinical Pharmacology & Therapeutics. 23(1):1-10, 1978 Jan.

PT      Publication Type: Journal Article

AB     Blind breaking is likely to occur in a long-term clinical trial involving subjects at risk. Double-blind conditions require subjects to live with ambiguity regarding their health status. It is unrealistic to expect them to tolerate this ambiguity over an extended period of time. A logical step for a subject is to break the blind and surreptitiously seek the best medical care available. Moreover, the staff assigned to monitor protocol adherence may further contribute to blind breaking because of ambiguity regarding their proper clinical role. Several steps are recommended to manage blind breaking within a trial, including improving the quality of medical care, more rigorous screening procedures, and maintaining a clinical environment that promotes accurate disclosure of blind breaking.

DE     Descriptors: Attitude of Health Personnel; *Double-Blind Method/px [Psychology]; Double-Blind Method/st [Standards]; Human; Patient Compliance; *Research Design; Research Personnel

 

 

AN     368823

AU     Reinharez D

TI      [Errors of the placebo test]. [French]

SO     Phlebologie. 31(4):313-20, 1978 Oct-Dec.

PT      Publication Type: Clinical Trial; Controlled Clinical Trial; Journal Article

AB     The difficulties inherent in clinical experimentation in phlebology, stem from the fact that they concern highly subjective functional problems, and are thus difficult to measure. The answer to these difficulties seems to be found in the use of the double blind method. This method, however, contains numerous causes of errors in phlebology, since in order to be mathematically applied to computer use, it is too sketchy and does not take into account many additional factors, incidental parameters and unfavorable coincidences related either to chronobiology (weather, seasonal changes), to hormonal problems (periods of the cycle, pregnancies, contraception, menopause), to the environment (professional posture, ground heat, periods of vacation or work), or associated diseases (neuro-vegetative and rheumatic disorders, excessive weight, metabolic disorders), etc. It seems that in such cases, wide experimentation, with a very critical clinician, who attributes the improvement obtained to the drugs prescribed only when left with no other possibility and after having eliminated all the coincidental factors, gives results closer to reality than double blind experiments, behind whose pseudo-scientific appearance lies a sketchiness that is the cause of numerous errors.

DE     Descriptors: Clinical Trials; Diagnostic Errors; *Double-Blind Method; Drug Evaluation; English Abstract; Environment; Hormones; Human; *Placebos; *Research Design; Time Factors

 

 

AN     334685

AU     Modestin J, Hodel J

TI      [How blind is a double-blind trial really? Validity of controlled investigations]. [German]

SO     International Pharmacopsychiatry. 12(3):129-36, 1977.

PT      Publication Type: Clinical Trial; Controlled Clinical Trial; Journal Article

AB     During a double blind trial lasting 4 weeks (Diazepam versus Loxapin), two investigators tried to identify the given drug prematurely. Only the more experienced investigator was able to identify the two drugs (p = 0.01). His judgement was based neither on observation of side-effects nor on a clinical improvement but apparently on a summary of particular subtle effects, the cognition of which requires a specific experience. The use of an adequate comparative drug instead of a placebo in a double blind study does not completely prevent a premature decoding but should reduce this risk and therefore increase the validity of the method.

DE     Descriptors: Anxiety/dt [Drug Therapy]; Clinical Trials; Comparative Study; Diazepam/tu [Therapeutic Use]; *Double-Blind Method/st [Standards]; Drug Evaluation; English Abstract; Human; Loxapine/tu [Therapeutic Use]; *Research Design/st [Standards]