Systemic immune-inflammation index as a predictor of statin residual cardiovascular risk compared with C-reactive protein.

BACKGROUND

Despite statins reducing cardiovascular (CV) disease risk, residual inflammatory risk persists in treated patients. The systemic immune-inflammation index (SII), integrating platelet, neutrophil, and lymphocyte counts, has emerged as a novel biomarker of systemic inflammation and immune dysregulation. This study evaluated the systemic immune-inflammation index (SII) as a predictor of residual CV mortality compared to C-reactive protein (CRP) in statin users.

METHOD: This study included 8211 adults with statin use from the National Health and Nutritional Examination Surveys (NHANES) 1999-2018 and were followed for survival through December 31, 2019. Cox proportional hazard models were used to investigate the associations between natural log-transformed SII (lnSII) and cardiovascular mortality. Predictive accuracy was compared via receiver operating characteristic (ROC) curves.

RESULT: During the follow-up period of 6.92 (3.75, 11) years, a total of 2261 all-cause deaths and 796 cardiovascular deaths were recorded. After adjusting for covariates, higher baseline SII was significantly associated with an elevated risk of CV mortality (hazard ratio [HR] for per unit increase in natural log-transformed SII (lnSII), 1.241; 95 % confidence interval [CI], 1.009-1.527). The ROC curve analysis demonstrated SII's superior predictive accuracy (AUC, 0.760; 95 %CI, 0.744-0.776) over CRP (AUC, 0.749; 95 % CI, 0.733-0.765).

CONCLUSION

Among patients receiving contemporary statins, SII was shown to be an independent predictor of future CV death. SII outperformed CRP as an inflammatory biomarker for residual CV risk in statin-treated patients.