Systemic Immune-Inflammation Index as A Predictor of Mortality and Rehospitalization in Heart Failure Patients

ABSTRACT Systemic Immune-Inflammation Index as A Predictor of Mortality and Rehospitalization in Heart Failure Patients Background Heart failure (HF) is a disease closely associated with inflammation and the Systemic Immune inflammation Index (SII) is a novel inflammatory marker. SII is a combined inflammatory indicator that incorporates three significant immune cells namely neutrophils, lymphocytes and platelets. SII is considered an excellent indicator of local immune response and systemic inflammation. SII is an inexpensive and easily accessible laboratory test in peripheral health facilities. Research Objective This study aims to determine whether SII can be used as a predictor of clinical outcomes, which are mortality and rehospitalization in patients with chronic heart failure. Research Methods This study is a retrospective cohort study using data of chronic heart failure patients who underwent hospitalization from the HF (Heart Failure) registry of Dr. Sardjito Hospital for the period January 2022 - February 2023. SII was calculated as platelet count × absolute neutrophil count / absolute lymphocyte count. Results There were 188 patients who met the inclusion criteria as research subjects from 282 chronic heart failure patients who underwent hospitalization. Subjects had a mean age of 58.80 ± 11.48 years. A total of 67,6% (n=127) of the subjects were male. SII value for mortality based on receiver operating characteristic (ROC) cut-off was 1459,59 (area under curve (AUC) 0.600, sensitivity (Sn) 55,6%, specificity (Sp) 68,8%) and the ROC cut-off for rehospitalization was 0,474. Kaplan-Meier analysis of SII with mortality, subjects with high SII values (>1459.59) had a 50,5% survival rate with a mean survival of 8,5 months and low SII (<1459.59) had a 74% survival rate with a mean survival of 9,9 months. Multivariate regression analysis found SII as an independent predictor of mortality odds ratio (OR 3,08, 95% confidence interval (CI) 1,59 – 5,95, p=<0.001) but not significant for rehospitalization. Conclusion Systemic Immune-inflammation Index (SII) is an independent predictor of mortality, but not a predictor of rehospitalization in chronic heart failure patients undergoing hospitalization. Keywords: Systemic Immune-inflammation Index (SII), heart failure (HF), mortality and rehospitalization