Dose relationship between oral glucocorticoids and tumor necrosis factor inhibitors and the risk of hospitalized infectious events among patients with rheumatoid arthritis

The objective of this study was to evaluate the impact of oral glucocorticoid (GC) dose on rates of hospitalized infectious events (HIEs) among RA patients newly exposed to tumor necrosis factor inhibitor (TNFi) therapy. This retrospective cohort study used data from the MarketScan claims database. Incident and prevalent adult RA patients newly exposed to TNFi therapy were identified and assigned to three cohorts: no GC, low-dose GC (≤7.5 mg), and high-dose GC (>7.5 mg); patients could contribute exposure time to multiple cohorts if they changed dose or discontinued GC. The primary outcome was estimated incidence rate (IR) of HIEs per 100 patient-years of GC exposure. A total of 40,933 eligible patients were identified (mean age 53.0 years; 77.4% female). HIE risk increased with increasing GC dose: the IR [95% confidence interval (CI)] was 3.9 (3.63–4.13) for no GC; 6.4 (5.68–7.16) for low-dose GC; and 13.3 (11.9–15.5) for high-dose GC. Adjusted rate ratios (95% CI) were 1.4 (1.21–1.60) for low-dose vs no GC; 2.8 (2.32–3.34) for high-dose vs no GC, and 2.0 (1.66–2.45) for high-dose vs low-dose GC. The risk of HIEs increased with increasing age. HIE risk did not increase with longer exposure to GCs. Oral GCs, regardless of dose, significantly increased the risk of HIEs among RA patients newly initiating TNFi therapy. Steroid dosing must be considered when assessing infection risk in treatment decisions for RA patients.