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

BACKGROUND: 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. OBJECTIVE: 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. DESIGN: A longitudinal observational analysis was performed on data from a nationwide RA registry. METHODS: 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. RESULTS: 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. CONCLUSION: 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.