Development of anthralin short-contact therapy in psoriasis: survey of published clinical trials

In a survey of clinical trials concerning the efficacy of short-contact therapy with anthralin in psoriasis vulgaris, focusing principally on methodologic issues, twenty-four papers published between January 1982 and December 1989, in English, French, and Italian, were selected. Nine of 24 papers reported on more than one trial, giving a total of 37 clinical trials to be evaluated. A great heterogeneity was evident in many aspects of the design and conduct of these trials, making pooling of results impossible. Most trials suffered from flaws in general methodologic aspects such as randomization and blinding. Limitations in general applicability of results were discussed with reference to the popular use of self-control design and selection of composite indexes (e.g., PASI) as an outcome variable. Published trials are not a reliable guide to clinical decisions concerning short-contact therapy, and some methodologic observations we made could be of general interest in designing clinical trials of psoriasis.