The randomized clinical trial: bias in analysis

The realization that bias in patient selection may influence the results of clinical studies has helped to establish the randomized controlled clinical trial in medical research. However, bias can be equally important at other stages of a trial, especially at the time of analysis. Withdrawing patien...

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Bibliographic Details
Published inCirculation (New York, N.Y.) Vol. 64; no. 4; pp. 669 - 673
Main Authors May, G S, DeMets, D L, Friedman, L M, Furberg, C, Passamani, E
Format Journal Article
LanguageEnglish
Published United States 01.10.1981
Subjects
Acute Disease
Alprenolol - therapeutic use
Atenolol - adverse effects
Clinical Trials as Topic
Clofibrate - therapeutic use
Double-Blind Method
Humans
Myocardial Infarction - diagnosis
Myocardial Infarction - drug therapy
Myocardial Infarction - mortality
Patient Compliance
Placebos
Propranolol - adverse effects
Random Allocation
Sulfinpyrazone - therapeutic use
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Summary:The realization that bias in patient selection may influence the results of clinical studies has helped to establish the randomized controlled clinical trial in medical research. However, bias can be equally important at other stages of a trial, especially at the time of analysis. Withdrawing patients from consideration in the analysis because of ineligibility on account of study entry criteria, lack of compliance to the protocol, or data of poor quality may be a source of systematic error. Examples to illustrate the possible consequences are taken from trials in the cardiovascular field. We recommended that reported study results should include outcome data from all subjects randomized in the group to which they were originally assigned.
ISSN:0009-7322
1524-4539
DOI:10.1161/01.CIR.64.4.669