To examine associations of anti-cyclic citrullinated peptide (aCCP) antibody and rheumatoid factor (RF) concentrations with future disease activity in men with rheumatoid arthritis (RA).
Outcome measures were examined in male US veterans with RA and included (1) proportion of observations in remission (disease activity score (DAS28) < or =2.6); (2) remission for > or =3 consecutive months; and (3) area under the curve (AUC) for DAS28. The associations of autoantibody concentration (per 100 unit increments) with outcomes were examined using multivariate regression.
826 men with RA were included in the analysis; the mean (SD) age was 65 (10.5) years and follow-up was for 2.6 (1.3) years. Most were aCCP (75%) and RF (80%) positive. After multivariate adjustment, aCCP (OR 0.93; 95% CI 0.89 to 0.96) and RF concentrations (OR 0.92; 95% CI 0.90 to 0.94) were associated with a lower odds of remission, a lower proportion of observation in remission (p=0.017 and p=0.002, respectively) and greater AUC DAS28 (p=0.092 and p=0.007, respectively). Among patients with discordant autoantibody status, higher concentrations of both aCCP and RF trended towards an inverse association with remission (OR 0.93; 95% CI 0.83 to 1.05 and OR 0.80; 95% CI 0.59 to 1.10, respectively).
Higher aCCP concentrations (particularly in RF-positive patients) are associated with increased disease activity in US veterans with RA, indicating that aCCP concentration is predictive of future disease outcomes in men.