Presence of Autoantibodies in Males and Females with Rheumatoid Arthritis: A Systematic Review and Meta-Analysis

Objective Rheumatoid arthritis (RA) is more common in females and although the cause of RA is unknown, it is characterized by the production of autoantibodies. The aim of this study is to determine whether RA-associated autoantibodies are more often found in females than males and identify factors that influence the relationship between sex and seropositivity. Methods Databases were searched and studies of RA (N ≥100) were included if they reported proportion of seropositive RA patients by sex. Meta-analyses and meta-regression were conducted using the random effects model. Covariates regressed were smoking, age, body mass index (BMI), the Health Assessment Questionnaire-Disability Index (HAQ) and the Disease Activity Score-28 (DAS-28). Results Eighty-four studies with a total of 141,381 subjects for RF seropositivity and 95,749 subjects for ACPA seropositivity met inclusion criteria. The mean age of participants ranged from 37-68 years and the proportion of female subjects ranged from 9-92%. Results indicated that females were less likely than men to be seropositive: OR=0.84[95%CI 0.77, 0.91] for RF and 0.88[95%CI 0.81, 0.95] for ACPA. BMI, smoking, mean age, DAS-28, and HAQ did not affect the relationship between sex and seropositivity. Conclusion Although studies report that females have higher RA disease activity than males and that seropositivity predicts worse outcomes, females were less likely to be seropositive than males.