Increased Risk of Acute Myocardial Infarction in Systemic Sclerosis: A Nationwide Population-based Study

Abstract

PurposeSystemic sclerosis is a life-threatening autoimmune disease characterized by vasculopathy, which results in myocardial involvement in an extremely high percentage of patients. Nevertheless, there have been no large-scale epidemiological studies about the risk of acute myocardial infarction in patients with systemic sclerosis. The aims of this study were to evaluate the hazard ratio (HR) and risk factors of acute myocardial infarction in patients with systemic sclerosis, as well as to compare the risks of acute myocardial infarction among systemic sclerosis patients taking different immunosuppressors. MethodsThe study cohort included 1344 patients with systemic sclerosis and 13,440 (1:10) age-, sex-, and comorbidity-matched controls during the period between 1997 and 2006, from the National Health Insurance Research Database. We compared the risk of acute myocardial infarction between patients with systemic sclerosis and controls and calculated the adjusted HRs for acute myocardial infarction in systemic sclerosis patients taking immunosuppressors and not taking immunosuppressors. ResultsThe incidence rates of acute myocardial infarction were 535 and 313 cases per 100,000 person-years for systemic sclerosis cohort and reference cohort, respectively (P <.001, unadjusted). After adjusting for age, sex, and underlying medical diseases on Cox proportional hazards model, systemic sclerosis was found to be an independent risk factor for acute myocardial infarction (HR 2.45). Other risk factors included hypertension (HR 2.08) and diabetes (HR 2.14). The multivariate adjusted HR for acute myocardial infarction did not decrease among the systemic sclerosis patients taking systemic steroids, penicillamine, cyclophosphamide, azathioprine, methotrexate, or cyclosporine. ConclusionSystemic sclerosis is independently associated with an increased risk of acute myocardial infarction. Immunosuppressors do not lower the risk of acute myocardial infarction in our study.