THURSDAY, Nov. 9 (HealthDay News) -- There is wide variation in the use of placebo controls in psoriasis studies, depending on location and funding source, according to a report published in the November issue of the Journal of the American Academy of Dermatology.
David J. Margolis, M.D., Ph.D., of the University of Pennsylvania School of Medicine in Philadelphia, and colleagues reviewed 135 trials published between 2001 and 2005, and found that 83 trials enrolling 8,171 subjects (41.7 percent) only used active controls, while 52 trials with 11,406 subjects (58.3 percent) used placebo controls.
Trials conducted in the United States and those funded by pharmaceutical companies were more likely to use placebos, the review revealed. The predicted frequency of placebo use was 77.6 percent for industry-funded trials conducted in the United States, versus 18.6 percent for non-industry trials conducted outside the United States.
These variations cannot be explained by trial design issues such as the number of participants or the primary focus of the study, nor by disease type or severity, the authors conclude. "These findings suggest that ethical and scientific issues related to choice of control group are interpreted in a markedly different fashion depending on trial location and funding source."
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