Sex differences in pain scores and localization in inflammatory arthritis: a systematic review and metaanalysis.

Objective: To systematically identify and examine reports of sex-stratified pain measurements in patients with inflammatory arthritis.

Methods: Data sources included PubMed (1950 to April 2010), Embase (1980 to April 2010), and manual searches of reference lists and conference abstracts. We included cohort studies and randomized trials comparing pain scores, treatment efficacy at reducing pain, or pain localization, between females and males with inflammatory arthritis [rheumatoid arthritis (RA), ankylosing spondylitis, psoriatic arthritis, and reactive arthritis].

Results: Twenty-six cohorts and 1 randomized trial reported sex-stratified pain scores, and all but 1 cohort identified worse pain scores at enrollment in females. In a metaanalysis of mean visual analog scale (VAS) scores (0 to 10) in 16 RA cohort studies (reporting on 21,612 females and 6871 males), the standardized mean difference in VAS was 0.21 (95% CI 0.16, 0.26). Treatment with disease-modifying therapy results in improvement in mean scores for both sexes; however, female absolute scores remain higher. In 12 spondyloarthropathy cohorts reporting pain localization, females develop more peripheral arthritis during their disease course (68.9% vs 51.2%) but less inflammatory back pain (50.6% vs 66.4%).

Conclusion: We identified important sex differences in pain scores in inflammatory arthritis, with higher pain levels in females. In spondyloarthritis, females develop more peripheral arthritis and have less frequent spinal involvement compared to males. These differences may affect a clinician's perception of disease severity and activity, and thus influence management decisions.