The evolving demographics of participants in psoriatic arthritis phase III randomised controlled trials of...

To characterize the evolving demographics of participants recruited to phase III randomised controlled trials (RCTs) of biologic/targeted synthetic disease-modifying anti-rheumatic drugs (b/tsDMARDs) in peripheral psoriatic arthritis (PsA).

We conducted a systematic review of EMBASE, MEDLINE, and the Cochrane Database of Clinical Trials (CENTRAL) to identify all placebo-controlled phase III RCTs of b/tsDMARDs in peripheral PsA published up to 1 June 2022. Data extracted included inclusion criteria, date of initiation, countries in which studies were conducted, age, sex, race, disease duration, swollen joint count, tender joint count, Health Assessment Questionnaire - Disability Index, Psoriasis Area and Severity Index, and radiographic damage scores. Trends over time were evaluated using descriptive statistics.

34 eligible RCTs from 33 reports were included. The proportion of female participants increased over time with females representing 29.0-43.7% of participants in studies initiated in 2000-2004 which increased to 46.0-58.8% in 2015-2019. While the number of countries included in RCTs increased significantly from 1-8 countries (2000-2004) to 2-46 (2015-2019), the proportion of white participants changed marginally from 90.0-98.0% (2000-2004) to 80.9-97.3% (2015-2019). The SJC and TJC decreased from 13.9 to 24.6 respectively (2000-2004), to 7.0-13.9 and 12.9-24.9 (2015-2019). Baseline CRP and HAQ-DI remained stable.

Despite the expansion of countries from which PsA RCT participants were recruited from, non-white participants continue to be under-represented. Improving diversity in patient representation is imperative to further our understanding of PsA phenotypes, proteogenomics, socioeconomic determinants, and treatment effects, to advance the care of all patients with psoriatic disease.