Orthopaedic corticosteroid injection and risk of acute coronary syndrome : a case control study

Katharine Thomas, Yochai Schonmann

Keywords: acute coronary syndrome; corticosteroid injections; intra-articular injections; orthopaedics; rheumatology

Background:
Intra-articular and soft tissue corticosteroid injection, (CSI) is a common treatment for musculoskeletal conditions and is considered safe with a low incidence of minor side effects. An association between musculoskeletal CSI and acute ischemic heart disease is not known.

Research questions:
Do musculoskeletal corticosteroid injections increase the incidence of acute coronary syndrome?

Method:
Data were reviewed from 41,276 patients, aged forty years of age or older and hospitalised with Acute Coronary Syndrome (ACS) between January 2015 and December 2019. Each ACS case was allocated up to ten control patients, drawn from their primary care clinic and matched for age and sex. The incidence of an orthopaedic or rheumatalogical consultation including a corticosteroid injection prior to the date of hospital admission was compared between the case and control groups.

Results:
A total of 413,063 patients were reviewed, 41,276 ACS cases and 371,787 controls. The mean age was 68.1 Standard deviation (SD) =13.1, 69.4% male. In the week prior to hospital admission 118 injections were received by the ACS patients and 495 in the control group. Odds Ratio, [OR] =1.95 (1.56-2.43). An association between ACS and prior CSI was strongest in the days immediately prior to hospitalisation: OR= 3.11 (2.10-4.61) for patients who were injected one day before ACS; OR = 2.33 (1.74-3.10) for patients injected in the three days prior to ACS. The statistical association between CSI and ACS gradually declined as the time between the injection and the hospitalisation increased, losing significance at ninety days, OR= 1.08 (0.98-1.18). The association between CSI and ACS remained robust when cardiovascular risk factors and history of rheumatological disease were taken into consideration.

Conclusions:
CSI for musculoskeletal conditions appear to substantially increase the risk of ACS in the days following the injection. Although the absolute risk of ACS is small, the effect size is clinically significant.

Points for discussion:
Should corticosteroid injections be re-evaluated as a “safe” option for treating musculoskeletal conditions.