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How blind was the patient blind in AMIS?
Author(s) -
Howard Jan,
Whittemore Alice S,
Hoover J Joanne,
Panos Mark
Publication year - 1982
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/clpt.1982.201
Subject(s) - medicine , placebo , double blind , aspirin , clinical pharmacology , psychology , alternative medicine , pharmacology , pathology
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 by 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. Clinical Pharmacology and Therapeutics (1982) 32, 543–553; doi: 10.1038/clpt.1982.201