Representation of adults with rheumatoid arthritis in US-based randomized controlled exercise trials: a systematic review with meta-analysis

The purpose of this study was to conduct a systematic review with meta-analysis to determine the representation of adults with rheumatoid arthritis (RA) according to sex, race, and ethnicity in exercise randomized controlled trials (RCTs) conducted in the USA. Exercise RCTs >= 4 weeks conducted in the USA in adults >= 18 years with RA were eligible. Studies were retrieved by searching six electronic databases, cross-referencing and searching a clinical trials registry. Dual, independent, study selection and data abstraction were conducted. The primary outcomes were the proportion of participants in each study according to sex as well as race/ethnicity. Results were pooled meta-analytically using the inverse-variance heterogeneity (IVhet) model after applying the double-arcsine transformation. Of the 1030 unique articles screened, five RCTs representing 353 participants with RA were included. The pooled participant prevalence was 83% (95% CI = 73 to 92%) for women and 17% (95% CI = 8 to 27%) for men, suggesting an over-representation of women and an under-representation of men by approximately 7.4% based on current prevalence US estimates for each. Qualitative examination for race and ethnicity demonstrated an under-representation of racial/ethnic minority groups. There is a lack of representation of men with RA in US-based randomized controlled exercise intervention studies. Additional US-based randomized controlled exercise trials, including greater inclusion and reporting of the racial/ethnic composition of participants, are also needed.