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OBJECTIVES: To systematically assess the kind of placebos used in investigator-initiated randomized controlled trials (RCTs), from where they are obtained, and the hurdles that exist in obtaining them. STUDY DESIGN AND SETTING: PubMed was searched for recently published noncommercial, placebo-controlled randomized drug trials. Corresponding authors were invited to participate in an online survey. RESULTS: From 423 eligible articles, 109 (26%) corresponding authors (partially) participated. Twenty-one of 102 (21%) authors reported that the placebos used were not matching (correctly labeled in only one publication). The main sources in obtaining placebos were hospital pharmacies (32 of 107; 30%) and the manufacturer of the study drug (28 of 107; 26%). RCTs with a hypothesis in the interest of the manufacturer of the study drug were more likely to have obtained placebos from the drug manufacturer (18 of 49; 37% vs. 5 of 29; 17%). Median costs for placebos and packaging were US$ 58,286 (IQR US$ 2,428- US$ 160,770; n = 24), accounting for a median of 10.3% of the overall trial budget. CONCLUSION: Although using matching placebos is widely accepted as a basic practice in RCTs, there seems to be no standard source to acquire them. Obtaining placebos requires substantial resources, and using nonmatching placebos is common.

Original publication




Journal article


J clin epidemiol

Publication Date





70 - 78


Investigator-initiated trials, Matching, Placebo, Randomized controlled trial