The Association Between Systemic Immune Inflammation Index and Intermediate-Term Mortality in Patients with Acute Coronary Syndromes

Background: ic immune inflammation has been investigated as a prognostic marker for different disea-ses. Considering the pivotal role of inflammation in the pathogenesis of acute coronary syndrome (ACS), it is paramount to predict the prognosis of patients with ACS. Therefore, we evaluated the association between inflammation measured by the systemic immune-inflammation index (SII) and middle-term mortality in patients with ACS. Materials and Methods: This single-center, retrospective study was composed of 539 patients with ACS (139 unstable angina pectoris USAP, 165 non-ST-elevation myocardial infarction NSTEMI, and 235 ST-elevation myocardial infarction STEMI) aged over 18 years. Descriptive statistics and multivari-ate regressions were used to examine the association between clinical and laboratory parameter characteristics and 12-month mortality. Results: The median age of the patients was 58 (50-67) and 73.1% of the patients were male. A total of 20 patients died in the next twelve months after ACS event. The median SII levels were highest in patients with STEMI 1301.96 (816.81-2174.53) , followed by NSTEMI 955.50 (619.99-1576-06 and USAP 595.32 (437.52-918.27) (p0.001). The SII had moderate success for the prediction of the intermediate-term mortality (AUC: 0.653, 95% CI: 0.526-0.779, p=0.024). In multivariate analyses, every 100-unit increase in SII was associated with a two percent increase in the risk of intermediate mortality (OR: 1.020, 95% CI: 1.004-1.037, p=0.016). Conclusions: We demonstrated that ACS patients with higher SII levels had a higher risk of mortality at twelve months, and higher SII levels were associated with a more severe underlying ACS etiology. If supported by prospective evidence, the SII index may guide clinicians in terms of both ACS severity and subsequent one-year survival rates.