Abstract 12358: Epidemiology of Acute Myocardial infarction in Systemic Sclerosis: Incidence and Outcomes

Abstract

Introduction: Risk of acute myocardial infarction (AMI) in inflammatory arthritides like rheumatoid arthritis (RA) is elevated. However, in autoimmune disorders with microvascular dysfunction, like systemic sclerosis (SS), the risk of AMI and its outcomes are not known. Methods: In the National Inpatient Sample (2003-2012), we used ICD9 codes to identify patients (≥18 years) with a primary diagnosis of AMI and a concurrent diagnosis of SS. We estimated population of SS at risk for AMI during each year by multiplying the previously reported stable SS prevalence of 276/million by the US adult population for the corresponding year. We used survey-analysis to generate national estimates for incident AMI and calculated incidence of AMI among SS patients by dividing the number of AMI patients during each year by the at-risk SS population. Characteristics and outcomes of AMI in SS were compared to those with RA and those without rheumatologic disease. Results: During 2003-2012, there were 4570 admissions for AMI in patients with SS in the US for an average of 63,121 at-risk SS patients each year. The incidence of AMI in patients with SS was 721/100,000 at-risk SS patients, which is 3-fold higher compared to incidence of AMI in the general population and remained elevated during 2003-12 (Figure). AMI patients with SS were younger, more likely to be female but were less likely to present as STEMI compared to RA or those with no rheumatologic disease (Table). They were also less likely to undergo PCI than either group. In-hospital AMI mortality in SS was higher than RA or those without rheumatologic disease (risk-adjusted odds ratio 1.65, 95%CI 1.28, 2.11, Table). Conclusions: There is a three-fold increase in risk of AMI in SS compared to the general population. Among AMI patients, in-hospital mortality is significantly higher in SS patients, compared to patients with RA or without rheumatologic disease. Further investigation is warranted to further assess measures to mitigate this risk.