AB144. Demographic and geographic diversity in chronic spontaneous urticaria clinical trials through a health equity lens: insights from 39 studies

Background: Approximately 0.9% to 1.4% of the population worldwide has a history of chronic spontaneous urticaria (CSU), which often remains suboptimally controlled with substantial biopsychosocial burden. While clinical trials have transformed CSU management, racial and ethnic disparities exist in the enrollment of trial participants. In 2016, the United States Food and Drug Administration published guidance regarding the collection and reporting of race and ethnicity data in clinical trials. However, its impact on CSU trials remains unknown. This study aims to characterise patient recruitment in CSU trials and explore the effect of the 2016 guidance if any.

Methods: We performed a search of phase II/III clinical trials for CSU on the United States National Library of Medicine clinical trial registry (ClinicalTrials.gov). Information including dates, locations, and participants’ demographics (age, sex, race, and ethnicity) were retrieved for analysis. The characteristics of trials between 2002–2016 and 2017–2023 were compared.

Results: A total of 39 trials involving 9,768 patients were included for analysis. Overall, Europe and the Americas were the most involved regions, respectively participating in 29 (78.4%) and 23 (62.2%) of the analyzed trials. Participation significantly increased in both Western Pacific (26.3% vs. 66.7%, P=0.01) and South-East Asia (0.0% vs. 22.2%, P=0.046). Among the 22 completed trials with available results, only 54.5% (12/22) reported participants’ races, with 73.0% (2,642/3,620) of the participants being White. Reporting of racial data significantly improved from 25.0% (3/12) to 90.0% (9/10, P=0.004) between the two periods, with a significant change in racial makeup (White: 76.1% vs. 72.7%, Asian: 16.9% vs. 22.1%, Black: 3.2% vs. 2.0%, P<0.001). Ethnicity data was only available in 5 (22.7%) trials, where Hispanic/Latino participants constituted 7.2% (39/538) of the total with a significant increase (0.0% vs. 8.3%, P=0.01), although the reporting of which did not.

Conclusions: Persistent, albeit improving racial and ethnic disparities remain in CSU trials. Collective efforts are warranted to promote health equity in dermatological research.

Keywords: Chronic spontaneous urticaria (CSU); CSU trials; racial disparity; ethnic disparity