Risk of septic arthritis after corticosteroid joint injections: A retrospective propensity score-matched cohort analysis

Abstract

Background: Septic arthritis (SA) is a rare but serious complication of corticosteroid joint injections (CSI) that can lead to joint damage and possible mortality. There is limited research defining the true risk of SA following large joint corticosteroid injection. Objective: To determine the absolute and risks difference of SA after large joint corticosteroid injection. Design: A retrospective cohort study of electronic health records identified patients from a multicenter and nationwide database in the United States who had an ambulatory visit with a diagnosis of arthritis. The absolute risk of SA after a large joint corticosteroid injection was calculated, as was the risk difference based on presence or absence of large joint corticosteroid injection. To calculate the risk difference, patients were propensity-score matched (1:1) based on risk factors such as demographics, comorbidities, or nonhealth-related risk factors. The primary outcome was SA diagnosis between 1 and 21 days after the large joint corticosteroid injection. The risk of SA was compared between matched cohorts with 95% confidence intervals (CIs). Results: The absolute risk for SA was found to be 0.0018, whereas the risk difference of SA after major joint corticosteroid injection was 0.0010 and the risk without major joint corticosteroid injection was 0.0017. The risk difference for those with a large joint corticosteroid injection compared to the control group was −0.0007 (95% CI, −0.0009 to −0.0005, p