Comparison of remission criteria in patients with rheumatoid arthritis treated with biologic or targeted synthetic disease-modifying anti-rheumatic drugs: results from a nationwide registry.

Biologic or targeted synthetic disease-modifying anti-rheumatic drugs (b/tsDMARD) are widely used for treatment of rheumatoid arthritis (RA), enabling patients to better achieve remission. The objective of the study was to investigate and compare remission rates in RA patients treated with different b/tsDMARDs during the period 2013-2019. A longitudinal observational analysis was performed on data from a nationwide RA registry. Remission rates in the KOBIO-RA registry were defined by a disease activity score in 28 joints (DAS28), clinical disease activity index (CDAI), simplified disease activity index (SDAI), and Boolean-based assessment. After initiating treatment with b/tsDMARDs, yearly remission rates in response to b/tsDMARDs, either all or as subgroups (tumor necrosis factor-α inhibitors, tocilizumab, abatacept, and Janus kinase inhibitors), were investigated for 5 years. Sustained remission was defined as remission maintained for two consecutive years. Patients (N = 1805) who completed at least one follow-up visit were analyzed (mean age = 55 years; 83.2% female). At month 12, 56.0% of patients achieved remission based on DAS28-C-reactive protein (CRP), 36.2% on DAS28-erythrocyte sedimentation rate (ESR), 10.4% on CDAI, 12.7% on SDAI, and 12.9% on Boolean criteria. Sustained remission rates were 62%, 40%, 13%, 11%, and 8% for the DAS28-CRP, DAS28-ESR, Boolean, SDAI, and CDAI remission criteria, respectively. Remission rates using the DAS28 definition varied most among the b/tsDMARD subgroups. Assessment of sustained remission using the CDAI, SDAI, or Boolean criteria is more stringent, yet congruous with the DAS28-based criteria in RA patients treated with b/tsDMARDs.