Systemic Inflammatory Response Syndrome is an Independent Predictor of One-Year Mortality in Patients with Acute Myocardial Infarction

Background: Convincing evidence suggests that inflammatory biomarkers are associated with an increased risk among patients with acute myocardial infarction (AMI). However, the impact of systemic inflammatory response (SIRS) on one-year clinical outcomes remains uncertain. Herein we investigated the impact of SIRS on one-year mortality and major adverse cardiovascular events (MACE) in patients with AMI. Methods: We conducted a retrospective study that enrolled patients admitted due to AMI and who received coronary artery intervention from January 2012 to June 2014. SIRS was defined according to standard criteria as having two or more of the following: (1) body temperature < 36 or > 38 degrees C, (2) heart rate > 90 beats per minute, (3) respiratory rate > 20, or (4) white blood cell count < 4000/mm(3) or > 12,000/mm(3). The primary endpoint was one-year mortality. The secondary endpoint was a one-year MACE, including revascularization, AMI, and stroke. Results: A total of 330 AMI patients were enrolled in the study, and 121 study subjects (36.6%) met the SIRS criteria. AMI patients with SIRS on admission had significantly increased one-year all-cause mortality (control vs. SIRS: 21.1% vs. 33.1%, p = 0.026) and one-year MACE (35.9% vs. 53.7%, p = 0.022). Patients with SIRS had a higher incidence of one-year non-fatal myocardial infarction, but not non-fatal stroke. After multivariable adjustment, SIRS [hazard ratio (HR) = 1.773, 95% confidence interval (CI) = 1.097-2.886, p = 0.019] and age (HR = 1.038, 95% CI = 1.018-1.058, p < 0.001) were associated with enhanced risk of one-year mortality. Conclusions: This study revealed that AMI patients with SIRS on initial admission were associated with increased risk of one-year all-cause mortality.