Diversity in Axial Spondyloarthritis Drug Trials: Enrollment by Sex, Race, Ethnicity, and Geographic Region

To examine demographic and geographic diversity in axial spondyloarthritis (axSpA) drug trials.

We performed a descriptive epidemiological study using ClinicalTrials.gov data. We included completed phase II-IV drug trials in adults with axSpA, conducted between 2000 and 2023, with results posted on ClinicalTrials.gov. We extracted and analyzed data on sex, race, ethnicity, trial characteristics, and trial locations.

Fifty-nine trials with 16,162 participants were analyzed. Female individuals constituted 30% of participants overall: 25% in radiographic axSpA (r-axSpA) trials, 34% in axSpA trials, and 48% in nonradiographic axSpA (nr-axSpA) trials. Thirty-one trials (53%) reported race, and 12 (20%) reported both race and ethnicity. Race reporting increased from 9% of trials (2000-2010) to 53% (2011-2015) and 100% (2016-2020). Among 10,037 participants with race data, 82% were White, 15% Asian, 2% American Indian/Alaska Native, 1% Black, and 0.02% Native Hawaiian/Pacific Islander. Asian representation increased from 4% (2011-2015) to 19% (2016-2020) and American Indian/Alaska Native from 1% to 3%, whereas Black representation remained consistently low at 1%. Among 3577 patients with ethnicity data, 14% of participants were Hispanic/Latino, increasing from 1% (2011-2015) to 14% (2016-2020). Fifty-one trials with location data enrolled participants from 53 countries. Sub-Saharan Africa (0%) and South/Central Asia (2%) had the lowest geographic representation of enrollment sites.

The proportion of women enrolled in axSpA drug trials largely reflects disease demographics. Race and ethnicity reporting has improved over time. Whereas participation of Asian, American Indian/Alaska Native and Hispanic/Latino patients has increased, Black and Native Hawaiian/Pacific Islander representation has remained low. Future efforts should prioritize inclusivity and participation in underrepresented regions globally.