Register-based observational study of associations between inflammatory remission, formal treatment targets and the use of disease-modifying antirheumatic drugs among patients with early rheumatoid arthritis

Abstract

Objective To assess associations between inflammatory remission, formal treatment targets and the likelihood of starting a new disease-modifying antirheumatic drug (DMARD), among patients with early rheumatoid arthritis (RA).Methods Patients newly diagnosed with RA were identified in the Swedish Rheumatology Quality Register (n=11 784). Disease Activity Score 28 (DAS28) and DMARD-treatment were assessed at RA diagnosis and 3, 6, 12 and 24 months thereafter. Inflammatory remission was defined as: swollen joints (0–28)=0 and C reactive protein <10 mg/L and normal erythrocyte sedimentation rate. The primary treatment target was DAS28 remission (<2.6). The proportion of patients in inflammatory remission who failed to reach DAS28 targets was assessed at each follow-up visit, and their likelihood of starting a new DMARD was compared with patients in inflammatory remission who reached the treatment target. rate ratios (RR) and 95% CIs were estimated with modified Poisson regression.Results Overall, 34%, 39%, 44% and 47% were in inflammatory remission at 3, 6, 12 and 24 months. Among these, 20%, 22%, 20% and 19%, respectively, failed to reach DAS28 remission. Patients who failed to reach DAS28 remission despite being in inflammatory remission were more likely to start a new DMARD treatment (RR (95% CI) at 6 months=1.59 (1.29 to 1.96), 12 months=1.52 (1.23 to 1.87)) and 24 months=1.47 (1.20 to 1.80).Conclusion Failing to reach formal treatment targets, despite being in inflammatory remission, is common among patients with early RA, and is associated with an increased likelihood of starting a new DMARD-treatment.