Intra-articular and soft-tissue corticosteroid injections and risk of infections: Population-based...

Chronic and short-term treatment with oral corticosteroids is associated with an increased risk of infection. However, the potential risk of infection that may be associated with intra-articular and soft-tissue injections of corticosteroids has not been reported. The aim of this study was to assess the risk for infection following intra-articular or soft-tissue corticosteroid injections.

Self-controlled-risk-interval study with 15 732 adults who were treated with intra-articular or soft-tissue corticosteroid injections during 2015-2018. The study was conducted in a large Israeli Health Maintenance Organization. We self-matched the participants and analyzed the incidence of infection over three periods: an exposure-period of 90 days following the injection, and two 90-day control periods. We identified the occurrence of several common infections in the patient's electronic medical record and analyzed the incidence rates of all infections (composite end-point) as well as each infection separately.

The incidence of any infection was higher during postexposure period compared with the control periods (46.5 vs. 42.1 events per 1000 persons), number needed to harm was 227 persons. Self-matching analysis showed increased incidence-rate-ratio (IRR) for the combined incidence of infections in the post-exposure period compared with the control periods (IRR = 1.10, 95% confidence interval [CI] 1.01-1.21). A sensitivity analysis showed that the highest IRR was during the first 30 days (IRR = 1.19, 95% CI 1.03-1.38), with higher IRR for patients aged 65 years and older (IRR = 1.37, 95% CI 1.08-1.73).

Intra-articular and soft-tissue corticosteroids injections may be associated with an increased risk of infections; however, the absolute risk increase is low.