Sex differences in clinical characteristics and their influence on clinical outcomes in an observational cohort of patients with rheumatoid arthritis.

Objective: Rheumatoid arthritis (RA) is more prevalent in women, but sex differences remain incompletely understood. This study aimed to elucidate sex differences in clinical characteristics and their potential impact on clinical outcomes in a large Korean cohort of patients with RA.

Methods: In total, 5376 RA patients from the KORean Observational study Network for Arthritis (KORONA) database were examined at baseline and for 3 consecutive years using the disease activity score 28 (DAS28), health assessment questionnaire (HAQ), and patient-reported outcomes (PROs). Within a subgroup with active disease (DAS28≥3.2) at baseline, sex impacts on clinical outcome during follow-up were analyzed using generalized estimating equation (GEE) models. The factors related to achieving clinical remission were analyzed using Cox-proportional hazard regression.

Results: At baseline, women (n=4574) were younger and had more erosive disease and longer disease duration than men (n=802) with higher scores in DAS28, HAQ, and PROs. The prevalence of interstitial lung disease, cardiovascular disease, and diabetes in men was higher than that of women. In a RA subgroup with active disease at baseline, GEE analyses demonstrated that women RA significantly influenced the rate of change of DAS28 over time. In that group, men are associated with achieving DAS28 sustained remission and point remission.

Conclusions: Women with RA in Korea report higher levels of disease activity and PROs compared to men, whereas most comorbidities were more prevalent in men. The longitudinal change in disease activity and the rate of achieving clinical remission were found to be worse in women with RA.