Healthy Skepticism Library item: 18605

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Publication type: Journal Article

Psaty BM, Prentice RL
Minimizing Bias in Randomized Trials
JAMA 2010 Aug 18; 304:(7):793-794
http://jama.ama-assn.org/cgi/content/extract/304/7/793

Abstract:

In 1992, Hansson et al1 proposed a novel design, the prospective randomized open trial with blinded end-point assessments. The lack of blinding of investigators and patients simplified the conduct of the trial, which would become more similar to routine medical practice than the blinded design. The use of blinding for the adjudication of outcomes would preserve the benefits of a fully blinded trial. A number of trials have used this design to evaluate antihypertensive agents and more recently antidiabetic agents.2-4 These trials were thought to produce valid and, perhaps, more generalizable results.

Studies of trial results for specific classes of treatments support the importance of investigator blinding. In a cross-sectional analysis of 192 trials that compared a statin drug with another statin or a nonstatin drug,5 the studies that described adequate blinding were much less likely to report findings that favored . . .