Background: Patients with rheumatoid arthritis (RA) are at increased risk for infection after arthroplasty, yet risks of specific biologic medications are unknown.
Objective: To compare risk for postoperative infection among biologics and to evaluate the risk associated with glucocorticoids.
Design: Retrospective cohort study.
Setting: Medicare and Truven MarketScan administrative data from January 2006 through September 2015.
Patients: Adults with RA who were having elective inpatient total knee or hip arthroplasty, either primary or revision, and had a recent infusion of or prescription for abatacept, adalimumab, etanercept, infliximab, rituximab, or tocilizumab before surgery.
Measurements: Propensity-adjusted analyses using inverse probability weights evaluated comparative risks for hospitalized infection within 30 days and prosthetic joint infection (PJI) within 1 year after surgery between biologics or with different dosages of glucocorticoids. Secondary analyses evaluated non-urinary tract hospitalized infections and 30-day readmissions.
Results: Among 9911 patients treated with biologics, 10 923 surgical procedures were identified. Outcomes were similar in patients who received different biologics. Compared with an 8.16% risk for hospitalized infection with abatacept, predicted risk from propensity-weighted models ranged from 6.87% (95% CI, 5.30% to 8.90%) with adalimumab to 8.90% (CI, 5.70% to 13.52%) with rituximab. Compared with a 2.14% 1-year cumulative incidence of PJI with abatacept, predicted incidence ranged from 0.35% (CI, 0.11% to 1.12%) with rituximab to 3.67% (CI, 1.69% to 7.88%) with tocilizumab. Glucocorticoids were associated with a dose-dependent increase in postoperative risk for all outcomes. Propensity-weighted models showed that use of more than 10 mg of glucocorticoids per day (vs. no glucocorticoid use) resulted in a predicted risk for hospitalized infection of 13.25% (CI, 9.72% to 17.81%) (vs. 6.78%) and a predicted 1-year cumulative incidence of PJI of 3.83% (CI, 2.13% to 6.87%) (vs. 2.09%).
Limitation: Residual confounding is possible, and sample sizes for rituximab and tocilizumab were small.
Conclusion: Risks for hospitalized infection, PJI, and readmission after arthroplasty were similar across biologics. In contrast, glucocorticoid use, especially with dosages above 10 mg/d, was associated with greater risk for adverse outcomes.
Primary funding source: Rheumatology Research Foundation, National Institutes of Health, and Bristol-Myers Squibb.