Statistical analysis
For analysis, patients were categorized into two groups according to the optimal cutoff value of SII level determined by using receiver operating characteristics curve analysis (low SII group <451.01 or high SII group ≥451.01). The SPSS 22.0 software (IBM Corp., Armonk, NY) was used to perform all analyses. Continuous variables were reported as the mean ± standard deviation (SD) and categorical data were reported as frequencies and percentages. Differences in baseline characteristics between two groups were compared using a χ2 test or Fisher’s exact test for categoric data and an independent t -test or Kruskal-Wallis test for continuous data, as appropriate. Kaplan-Meier survival curves were used for cumulative incidence rates of primary and secondary endpoints. The statistical differences between groups in Kaplan-Meier curves were determined using the log-rank test. The predictive value of SII level related to outcomes was assessed by the multivariable Cox regression model with adjustment for potential confounders, including age, diabetes mellitus, WBC, Hb, PLT, albumin, BUN, UA, Cr, HDL, eGFR, D-dimer, CRP, ESR, LAD and LVEF. The hazard ratios (HRs) and 95% confidence intervals (CIs) were also determined. All tests were 2-sided and a p value <0.05 was considered statistically significant.