Characteristics and completeness of clinical trial registrations in psoriasis and atopic dermatitis

Controversy over the failure to publish results of clinical trials linking antidepressant treatment to suicidal behaviour in adolescents has increased interest in clinical trial registration.

To assess numbers, characteristics and completeness of registrations of trials for psoriasis and atopic dermatitis registered at two web-based trial registries: ClinicalTrials.gov and isrctn.org.

In this cross-sectional study we identified trials by searching ClinicalTrials.gov and isrctn.org on 18 January 2006 for trials registered up to 31 December 2005. We included only trials of therapeutic interventions for atopic dermatitis or psoriasis. We ascertained the date of submission of registration, the funding source of the trial, and whether a registration listed the specific name of the intervention studied, the specific outcome measure used (e.g. "Psoriasis Area and Severity Index"), the criterion used to gauge success on the outcome measure (e.g. > or = 75% decrease), and the time at which the outcome would be assessed (e.g. at 12 weeks).

There were 156 registered trials, including 128 (82%) at ClinicalTrials.gov [36 (23%) in atopic dermatitis, 92 (59%) in psoriasis] and 28 (18%) at isrctn.org [23 (15%) in atopic dermatitis, 5 (3%) in psoriasis]. Pharmaceutical companies funded 87 trials (56%), federal or governmental agencies 28 (18%), universities or organizations 21 (13%), and a combination of funders 20 (13%). Of atopic dermatitis trials (13 of 36) and (24 of 92) of psoriasis trials at ClinicalTrials.gov were registered in September 2005. The specific name of the intervention studied was listed in 150 registrations (96%), 89 (57%) listed the specific measure used, 69 (44%) listed the criteria to gauge success and 62 (40%) listed the time of assessment.

While trial registrations in atopic dermatitis and psoriasis are increasing, more complete information in these registrations may increase their value for dermatologists and their patients.