Effect of investigator bias on clinical trials.
Two clinical trials were performed to determine the relative efficacy of tioconazole, a new antifungal agent for treating patients with tinea pedis. One study compared the new agent with a placebo cream and the other with miconazole nitrate, an established effective antifungal agent. The investigators found a much higher "cure" rate for tioconazole when both treatment groups were known to receive active agents than the cure rate for tioconazole found in the placebo-controlled study. These results showed that the expectations of investigators can influence their clinical evaluations. Such bias could also influence the results of clinical trials.
Smith
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Department of Dermatology, University of Texas Medical Branch, Galveston 77550.
D000935:Antifungal Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D002986:Clinical Trials as Topic / Q000592:standards*; D004311:Double-Blind Method; D005260:Female; D005533:Foot Dermatoses / Q000175:diagnosis / Q000188:drug therapy; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D008825:Miconazole / Q000009:adverse effects / Q000627:therapeutic use; D011897:Random Allocation
D000935:Antifungal Agents; D007093:Imidazoles; D008825:Miconazole; C020527:tioconazole