The evolving demographics of participants in psoriatic arthritis phase III randomised controlled trials of b/tsDMARDs: A systematic review

OBJECTIVES: 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).

METHODS: 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.

RESULTS: 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.

CONCLUSION: 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.