Selection of patients for psoriasis clinical trials: a survey of the recent dermatological literature

Reports of 62 psoriasis clinical trials listed in the Cumulated Index Medicos for the years 1988 and 1989 and published only in leading dermatological journals were evaluated for different elements of research methodology concerned with the recruitment of subjects. The evaluation included items such as eligibility criteria, the sampling process, ethical considerations and sample size calculation. Major weaknesses in the description of all aspects of the recruitment procedure were demonstrated. For example, a quantitative disease activity criterion at entry was mentioned in 15% of the studies, consecutive patients were included in 5% of the trials, sufficient information on ethical approval was given in 16% of the studies, and a pre-study sample size calculation was not mentioned in any of the trials.