Single high-dose intramuscular injection versus short-term low-dose oral glucocorticoids as bridging therapy in active rheumatoid arthritis: a retrospective cohort study on remission induction

Abstract

Objectives: Despite recommendations for short-term use, prolonged administration of low-dose glucocorticoids (GCs) remains common in rheumatoid arthritis (RA), raising concerns about associated adverse effects. Compound betamethasone injection, a long-acting GC with rapid and sustained effects, may offer a single-administration alternative. This retrospective cohort study aims to evaluate its bridging efficacy and safety versus conventional oral regimen. Methods: We retrospectively included 250 patients with active RA who received either a single intramuscular injection of compound betamethasone or oral prednisone, with a 24-month follow-up. Disease remission rate at the 3-month follow-up served as the primary outcome, assessed for non-inferiority (margin, − 20%). Secondary outcomes included disease activity, relapse, and adverse events. Multivariable regression and inverse probability weighting (IPW) were applied to balance baseline differences. Results: Exposed to significantly lower cumulative GC dose, the compound betamethasone injection group showed non-inferior remission at the 3-month follow-up, with risk differences (95% confidence intervals (CI)) of 0.1896 (0.0713 to 0.3052) and 0.2017 (0.0975 to 0.3059) for Index remission (multivariable regression and IPW-adjusted analysis, respectively) and 0.1984 (0.0751 to 0.3231) and 0.2062 (0.0894 to 0.3231) for Boolean remission. Consistently, non-inferiority appeared to be maintained during follow-up. Adjusted analysis suggested fewer relapses in the compound betamethasone injection group (p < 0.0001). GC-related infection and overall incidence of new-onset disorders were also reduced (multivariable regression and IPW-adjusted analysis, p < 0.05). Conclusion: Overall, single intramuscular administration of compound betamethasone was associated with non-inferior short-term bridging efficacy, long-term disease stability, fewer relapses, and GC-related adverse events with reduced GC exposure, compared to oral prednisone. (Table presented.)