Orthopaedic corticosteroid injections and risk of acute coronary syndrome: a cohort study

BACKGROUND: Corticosteroid injections (CSIs) are a common treatment for arthritis and other musculoskeletal conditions. AIM: To determine whether there is an increased incidence of acute coronary syndrome (ACS) following intra-articular and soft-tissue CSI. DESIGN AND SETTING: Cohort study in an urban primary care orthopaedic clinic. METHOD: Data were reviewed from all patients aged ≥50 years and seen by orthopaedic specialists between April 2012 and December 2015, including CSI, hospital admission in the week following the orthopaedic visit, and cardiovascular risk factors. The incidence of an ACS-associated hospital admission was compared between visits in which patients received CSIs and visits in which patients did not. RESULTS: A total of 60 856 orthopaedic visits were reviewed (22 131 individual patients). The mean age was 70.9 years (standard deviation [SD] = 10.8), and 66.5% were female. Injections were administered in 3068 visits (5.1%). In the week following the visit there were 25 ACS hospital admissions (41 per 100 000 visits); seven events were after visits with an injection, and 18 were after non-injection visits. Patients who had received an injection were more likely to experience a subsequent ACS. (227 versus 31 events per 100 000 visits, odds ratio [OR] = 7.3; 95% confidence interval [CI] = 2.8 to 19.1). The association between receiving a CSI and ACS remained similar when the analysis was restricted to subgroups defined by age, sex, and cardiovascular risk factors. CONCLUSION: CSI for musculoskeletal conditions may substantially increase the risk of ACS in the week following the injection. Although the absolute risk of ACS is small, the effect size appears to be clinically significant.