Objective: To examine whether disease duration is an independent predictor of achieving remission in rheumatoid arthritis (RA) patients initiating therapy.
Methods: RA patients in the Consortium of Rheumatology Researchers of North America registry newly prescribed a nonbiologic disease-modifying antirheumatic drug (DMARD) or anti--tumor necrosis factor (anti-TNF) with at least one followup visit were identified. Achievement of remission was defined using the Clinical Disease Activity Index (CDAI; score ≤2.8) and 28-joint Disease Activity Score (DAS28; score <2.6) at any followup visit within one year; sustained remission was defined as remission during any two successive visits. Likelihood of remission was examined through logistic regression based on 5-year increments of disease duration, adjusting for baseline covariates.
Results: Among the 1,646 nonbiologic DMARD initiators, CDAI remission occurred in 21.3% of those with ≤5 years of disease duration, 19.6% with 6-10 years, and 13.5% with ≥11 years (P < 0.001); sustained remission occurred in 10.2%, 8.8%, and 2.5%, respectively (P < 0.001). Results were similar among the 3,179 anti-TNF initiators (CDAI remission in 22.3%, 17.7%, and 12.8%, respectively [P < 0.001]; CDAI sustained remission in 9.7%, 9.5%, and 4.2%, respectively [P < 0.001]). DAS28 results were similar in both groups. In adjusted analyses, an increase of disease duration by 5 years was associated with a reduced likelihood of CDAI remission in nonbiologic DMARD (odds ratio [OR] 0.91, 95% confidence interval [95% CI] 0.83-0.99) and anti-TNF initiators (OR 0.88, 95% CI 0.83-0.94). A similar result was seen for sustained remission using the CDAI (nonbiologic DMARD: OR 0.61, 95% CI 0.48-0.76; anti-TNF: OR 0.85, 95% CI 0.75-0.97).
Conclusion: Earlier treatment was associated with a greater likelihood of remission.
Copyright © 2011 by the American College of Rheumatology.