Arterial Events in Persons with Dermatomyositis and Polymyositis

Abstract

Objective.To assess arterial events in dermatomyositis (DM) and polymyositis (PM), and associated factors.Methods.We studied a cohort of persons with DM and PM, assembled from provincial administrative databases. New cases of ischemic heart disease, cerebrovascular accidents (CVA), and peripheral arterial disease were ascertained from billing and hospitalization data. We performed case-control analyses to assess the effects of clinical factors and medication exposures.Results.Incident arterial events occurred in 80 subjects, including 34 acute myocardial infarctions (13.8/1000 person-years) and 13 CVA (5.1/1000); these rates are higher than available Canadian figures. Nested case-control analyses, with risk-set sampling, revealed an increased incidence of arterial events associated with hypertension [adjusted rate ratio (RR) 2.6; 95% confidence interval (CI) 1.2–5.5] and lipid disorders (adjusted RR 2.6, 95% CI 1.0–6.5), whereas nonsteroid immunomodulators (methotrexate, azathioprine, antimalarial agents, or cyclophosphamide) were inversely associated with arterial events (adjusted RR 0.5, 95% CI 0.2–1.0).Conclusion.We found a high incidence of arterial events in this cohort of persons with inflammatory myopathy. Traditional risk factors, particularly hypertension and lipid disorders, were predictors of arterial events, while nonsteroid immunomodulators were inversely associated. Our work suggests a rationale for aggressive risk reduction strategies in persons with inflammatory myopathies.