Racial and ethnic representation in systemic sclerosis clinical trials: a 25-year analysis of ClinicalTrials.gov (1999-2025)

Objectives: This study aimed to quantify reporting of race and ethnicity in systemic sclerosis (SSc) clinical trials, characterise geographic distribution, and assess participant representation relative to US population benchmarks.Methods: We conducted a cross-sectional analysis of registered SSc trials with enrolment data.Of 699 trials screened, 95 met initial criteria; after excluding 21 terminated and 4 non-SSc studies, 70 completed trials (n = 4956 participants) were analysed.We summarised the prevalence of race/ethnicity reporting and calculated race/ethnicity distributions among participants with available data.US Census estimates were used for contextual comparison.Trials were also grouped by recruiting continent.Results: Among 70 trials, 39 (55.7%) reported race and 26 (37.1%) reported ethnicity; 25 reported both, while 30 (42.9%) reported neither.Participant-level data were available for 3161 individuals for race (60.0% of all enrollees) and 2255 for ethnicity (47.1%).Among those with race reported, 78.5% were White (n = 2482), 12.7% Asian (n = 400), 4.9% Black or African American (n = 155), 1.4% multiracial (n = 45), 0.6% American Indian/Alaska Native (n = 18), and 0.3% Native Hawaiian/Other Pacific Islander (n = 8); 1.7% were unknown/unreported (n = 53).Of participants with ethnicity data (n = 2335), 10.9% were Hispanic/Latino, 86.6% not Hispanic/Latino, and 2.5% unknown/unreported.Trial activity was concentrated in North America (39.2%) and Europe (36.3%), with additional activity in Asia (16.6%);South America, Oceania, and Africa contributed smaller shares.Conclusions: Race/ethnicity reporting in SSc trials is incomplete, and available data reveal disproportionate underenrolment of Black and Hispanic/Latino participants relative to US population benchmarks.Standardised reporting and intentional, equity-focused recruitment are needed to enhance representativeness and interpretability of SSc trial findings.