Comparative risk of osteoporotic fracture among patients with rheumatoid arthritis receiving TNF inhibitors versus other biologics: a cohort study

In this population-based cohort study on comparative osteoporotic fracture risks between different biologic disease-modifying drugs among patients with rheumatoid arthritis (RA), we did not find a significant difference in the risk of osteoporotic fractures between RA patients receiving TNF inhibitors versus abatacept or tocilizumab. Introduction We aimed to investigate the comparative risk of osteoporotic fractures between rheumatoid arthritis (RA) patients who initiated TNF inhibitors (TNFis) versus abatacept or tocilizumab. Methods Using the Korea National Health Insurance Service datasets from 2002 to 2016, RA patients who initiated TNFis, abatacept, or tocilizumab were identified. The primary outcome was a composite end point of non-vertebral fractures and hospitalized vertebral fractures; secondary outcomes were two components of the primary outcome and fractures occurring at the humerus/forearm. Propensity score (PS) matching with a variable ratio up to 10 TNFi initiators per 1 comparator drug initiator was used to adjust for > 50 baseline confounders. We estimated hazard ratios (HRs) and 95% confidence interval (CI) of fractures comparing TNFi initiators to abatacept and to tocilizumab by Cox proportional hazard models stratified by a matching ratio. Results After PS-matching, 2307 TNFi initiators PS-matched on 588 abatacept initiators, and 2462 TNFi initiators on 640 tocilizumab initiators were included. A total of 77 fractures occurred during a mean follow-up of 454 days among TNFi and abatacept initiators and 83 fractures during 461 days among TNFi and tocilizumab initiators. The PS-matched HR (95% CI) was 0.91 (0.48-1.71) comparing TNFi versus abatacept initiators, and 1.00 (0.55-1.83) comparing TNFi versus tocilizumab initiators. Analysis on vertebral and non-vertebral fractures showed similar results. Conclusions In this nationally representative cohort, we did not find a significant difference in the risk of fractures between TNFi initiators versus abatacept or tocilizumab among RA patients.