Systemic Sclerosis Is Associated With Increased Inpatient Mortality in Patients Admitted for Acute Coronary Syndrome: Analysis of the National Inpatient Sample

Abstract

Objective: This study aims to compare the outcomes of patients primarily admitted for acute coronary syndrome (ACS) with and without systemic sclerosis (SSc). The primary outcome was odds of inpatient mortality. Hospital length of stay, total hospital charges, rates of cardiovascular procedures, and treatments were secondary outcomes of interest.

Methods: Data were abstracted from the National Inpatient Sample (NIS) 2016 and 2017 Database. The NIS was searched for hospitalizations for adult patients with ACS (ST-segment elevation myocardial infarction [STEMI], non-ST-segment elevation myocardial infarction [NSTEMI], and unstable angina) as principal diagnosis with and without SSc as secondary diagnosis using International Classification of Diseases, Tenth Revision codes. Multivariate logistic and linear regression analysis was used accordingly to adjust for confounders.

Results: There were more than 71 million discharges included in the combined 2016 and 2017 NIS database. There were 1,319,464 hospitalizations for adult patients with a principal International Classification of Diseases, Tenth Revision code for ACS. There were 1155 (0.09%) of these hospitalizations that had SSc. The adjusted odds ratios for inpatient mortality for ACS, STEMI, and NSTEMI hospitalizations with coexisting SSc compared with those without SSc were 2.02 (95% confidence interval [CI], 1.19-3.43; p = 0.009), 2.47 (95% CI, 1.05-5.79; p = 0.038), and 2.19 (95% CI, 1.14-4.23; p = 0.019), respectively.

Conclusions: Acute coronary syndrome hospitalizations with SSc have increased inpatient mortality compared with those without SSc. ST-segment elevation myocardial infarction and NSTEMI hospitalizations with SSc have increased inpatient mortality compared with STEMI and NSTEMI hospitalizations without SSc, respectively. Acute coronary syndrome hospitalizations with SSc have similar hospital length of stay, total hospital charges, rates of revascularization strategies (percutaneous coronary intervention, coronary artery bypass surgery, and thrombolytics), and other interventions (such as percutaneous external assist device and intra-aortic balloon pump) compared with those without SSc.