Patients with idiopathic inflammatory myopathies at high risk of acute coronary syndrome

The risk of acute coronary syndrome (ACS) is increased in individuals with idiopathic inflammatory myopathies (IIM), especially within the first year following diagnosis, according to a recent study.

The incidence rate of ACS was higher in IIM patients than in the general population, specifically among older individuals and within the first year of diagnosis. The overall incidence rate of ACS in IIM was 15.6 (95 percent confidence interval [CI], 11.7–20.4) per 1,000 person-years. Compared with the general population, those with IIM had a hazard ratio of 2.4 (95 percent CI, 1.8–3.2).

The increased risk of ACS in IIM individuals persisted even after accounting for the competing risk of death, with a cumulative incidence of 7 percent at 5 years compared to 3.3 percent in the general population.

This study sought to examine the risk of ACS in an IIM cohort vs the general Swedish population. The investigators identified 655 individuals with incident IIM and 6,813 general population comparators from national registries. IIM individuals were diagnosed between 2002 and 2011. Follow-up began at IIM diagnosis and corresponding date in the general population.

The International Classification of Diseases codes were used to define ACS, cardiovascular (CV) comorbidities and CV risk factors. The risk of ACS in IIM patients was compared with that in the general population using Cox proportional hazards models. Competing risk regression models were used to account for the competing risk of death.

“Evidence suggests an increased risk of CV diseases, including ACS, in IIM,” the investigators noted.