Five-Year Drug Survival and Discontinuation Reasons for Eight Biological Disease-Modifying Antirheumatic Drugs for Rheumatoid Arthritis: A Retrospective Analysis of 1182 Patients from the Niigata Orthopedic Surgery Rheumatoid Arthritis Database (NOSR

<b>Background</b>: Continuity of care for rheumatoid arthritis patients within regional networks enables stable long-term clinical data collection, despite chronic rheumatologist shortages in Japan. We determined 5-year drug survival and discontinuation reasons for eight biological disease-modifying antirheumatic drugs (bDMARDs) using a regional multicenter registry. <b>Methods</b>: We retrospectively analyzed 1182 patients initiating their first (naïve, <i>n</i> = 784) or subsequent (switch, <i>n</i> = 398) bDMARD between May 2001 and August 2022 across five institutions. The primary endpoint (5-year drug survival) and secondary endpoints (discontinuation risk factors and cumulative incidence of reasons) were evaluated using Kaplan-Meier curves, Cox proportional hazards, and Fine & Gray models. <b>Results</b>: Baseline characteristics varied significantly among bDMARDs. Five-year drug survival in the naïve cohort ranged from tocilizumab (50.8%) to golimumab (22.6%); in the switch cohort, from abatacept (42.6%) to infliximab (10.0%). In multivariable Cox analysis of naïve patients, male sex (hazard ratio [HR] = 1.49, 95% confidence interval [CI] = 1.09-2.02), lower baseline 28-joint Disease Activity Score with erythrocyte sedimentation rate (DAS28-ESR) (HR = 0.90, 95% CI = 0.82-0.99), and absence of methotrexate co-therapy (HR = 0.73, 95% CI = 0.55-0.97) predicted discontinuation. The lower baseline DAS28-ESR association potentially reflects successful courses toward intentional cessation following remission. Discontinuations were attributed to inadequate response (27.1%), non-adverse events (25.3%), and adverse events (17.3%). <b>Conclusions</b>: Tocilizumab and abatacept demonstrated the highest retention rates in biologic-naïve and switch cohorts, respectively. Early, individualized drug selection and dose optimization are crucial to maximizing long-term bDMARD effectiveness before switching.