Systemic Immune-inflammatory Index Predicts In-hospital And Long-term Prognosis For Elderly Patients With Acute Myocardial Infarction

Background:The inflammatory complex index have been shown that it was important in the prognosis of acute myocardial infarction(AMI).The systemic immune-inflammatory index(SII),as a novel biomarker,was calculated by the following formula:SII=(neutrophil count×platelet count)/lymphocyte count.Objective:Our work was to assess the relationship between SII and in-hospital and long-term clinical outcomes in elderly AMI patients.Methods:Our study retrospectively collected 711 consecutive elderly patients(65-85 years)who were diagnosed as AMI from January 2015 to December 2017 at Tongji Hospital.The enrolled patients were divided into ST-segment elevation myocardial infarction group and non-ST-segment elevation myocardial infarction(NSTEMI)group according to the disease types.The clinical endpoints were all-cause mortality and major adverse cardiovascular and cerebrovascular events(MACCE).All subjects were performed coronary angiography examination during hospitalization.Baseline data of enrolled patients were collected for the following analysis:(1)Using receiver operating characteristic curve to calculate the optimal cut-off value of SII.(2)The correlation between SII and other indicators were analyzed through Spearman correlation coefficient.(3)Kaplan-Meier method and the log-rank test were performed to compare the survival curves.Besides,we used the forward stepwise Cox regression analysis to determine the association between SII and clinical endpoints.Results:(1)To predict the in-hospital outcomes,the threshold of SII was1087.21×10~9/L.The sensitivity was 59.00%and the specificity was 68.50%.What’s more,using a cut point of 1423.12×10~9/L,SII predicted long-term clinical events with a sensitivity of 50.00%and a specificity of 74.10%.(2)Kaplan-Meier curves indicated that patients in the higher value of SII had significantly worse in-hospital and long-term outcomes than patients in the lower SII(log-rank test:P<0.01,P<0.01,P<0.01,P<0.01,respectively).(3)Correlation analysis results suggested that SII and Gensini score were positively related in NSTEMI patients(r=0.18,P<0.01).(4)At multivariate analyses,SII showed the independent predictive value for in-hospital mortality(harzard ratio[HR]=3.32,95%confidence interval[CI]=1.55–7.10,P<0.01),in-hospital MACCE(HR=1.43,95%CI=1.02–2.00,P=0.04),long-term mortality(HR=1.95,95%CI=1.23–3.09,P<0.01)along with long-term MACCE(HR=1.72,95%CI=1.23–2.40,P<0.01).Conclusion:(1)SII was an independent predictor of in-hospital and long-term all-cause mortality/MACCE in elderly patients with AMI.(2)In NSTEMI patients,SII was positively correlated with Gensini score.Our result suggested that SII could reflect the severity of coronary artery lesions to some extent.