Baseline disease duration of chronic spontaneous urticaria participants in phase III clinical trials

Chronic spontaneous urticaria often follows a prolonged and variable course, yet baseline disease duration is inconsistently reported in clinical trials, limiting interpretation of treatment outcomes. Accordingly, this systematic review aimed to evaluate baseline disease duration and reporting practices in phase-III trials for chronic spontaneous urticaria. Of 36 trials identified, only 16 (44.4%) reported baseline disease duration (mean: 5.30 ± 1.81 years). Differences in average disease duration were observed by publication date and intervention of interest. Definitions of disease duration were frequently unspecified, and no trials examined efficacy stratified by disease duration. This review ultimately highlights a gap in disease duration reporting, underscoring the need for standardization and transparency in clinical trial design.