Clinical outcomes of molecular-targeted therapies for rheumatoid arthritis: comparison between orthopaedic surgeons and rheumatologists in the multicenter retrospective ANSWER cohort

OBJECTIVES: In Japan, pharmacological treatment for rheumatoid arthritis (RA), including biologic disease-modifying antirheumatic drugs (bDMARDs) and Janus kinase inhibitors (JAKi), is provided by both orthopaedic surgeons and rheumatologists. However, differences in patient characteristics, treatment selection, and outcomes between these two clinical settings have not been fully elucidated. This study aimed to compare these factors using real-world data. METHODS: Using the ANSWER cohort, we identified 7268 RA treatment courses initiating bDMARDs or JAKi between August 2002 and May 2023. Patients were classified into orthopaedic surgeon-managed and rheumatologist-managed groups. Patient characteristics and treatment patterns were compared. Treatment retention due to ineffectiveness and adverse events was assessed using Cox proportional hazards models to estimate hazard ratios (HRs) adjusted for potential confounders. RESULTS: Compared with the rheumatologist-managed group, patients managed by orthopaedic surgeons had longer disease duration, higher seropositivity, greater functional impairment, although lower comorbidity prevalence such as hypertension, dyslipidemia, and diabetes mellitus. Methotrexate, tumor necrosis factor inhibitors, JAKi, and intra-articular injections were used more frequently, whereas oral glucocorticoids were used less frequently. After adjustment, treatment retention due to ineffectiveness was comparable between groups (HR 0.98, 95% CI 0.83-1.17), and changes in disease activity were similar. Discontinuation due to adverse events was significantly less frequent in the orthopaedic surgeon-managed group (HR 0.61, 95% CI 0.46-0.82). CONCLUSIONS: Despite differences in patient profiles and treatment patterns, molecular-targeted therapy managed by orthopaedic surgeons achieved comparable effectiveness and was associated with a lower risk of discontinuation due to adverse events compared with rheumatology care. Key Points • Patients managed by orthopaedic surgeons had longer disease duration, higher seropositivity, and more advanced structural and functional impairment than those managed by rheumatologists. • Despite these differences, treatment effectiveness and disease activity improvement with bDMARDs or JAK inhibitors were comparable between specialties after adjustment for confounders. • Treatment discontinuation due to adverse events was less frequent in patients managed by orthopaedic surgeons. • Guideline-based management may enable consistent clinical outcomes across different specialties in real-world rheumatoid arthritis care.