Comparative Analysis of Neutrophil-to-lymphocyte Ratio, Systemic Immune-Inflammation Index, and Prognostic Nutritional Index in Acute Myocardial Infarction Patients Treated with Percutaneous Coronary Intervention

Objective: Acute myocardial infarction constitutes one of the leading reasons for cardiac mortality. Therefore, early identification of high-risk patients provides better prognostic accuracy. This study aimed to investigate the prognostic significance of novel inflammatory biomarkers such as neutrophil-to-lymphocyte ratio, systemic immune-inflammation index, and prognostic nutritional index in acute myocardial infarction patients treated with percutaneous coronary intervention and to compare their predictive abilities with each other. Methods: A total of 828 acute myocardial infarction patients treated with percutaneous coronary intervention were retrospectively analyzed. The inflammatory indices, such as neutrophil-to-lymphocyte ratio, systemic immune-inflammation index, and prognostic nutritional index, were calculated by admission blood tests. The study population was divided into 2 groups according to the occurrence of major adverse cardiac events, which were defined as all-cause mortality, non-fatal myocardial infarction, and cerebrovascular events. Results: Multivariate Cox regression analysis determined prognostic nutritional index as an independent predictor of major adverse cardiac event and all-cause mortality (hazard ratio: 1.05, 95% CI: 1.02-1.07, P <.001 for major adverse cardiac event and hazard ratio: 1.05, 95% CI: 1.02-1.09, P =.002 for all-cause mortality). Receiver operating characteristic curves revealed that the predictive value of prognostic nutritional index with both regard to major adverse cardiac event and all-cause mortality was better than the systemic immune-inflammation index and neutrophil-to-lymphocyte ratio (by DeLong method, area under curve PNI vs. area under curve SII z test = 2.66, P =.008; area under curve PNI vs. area under curve NLR z test = 2.8, P =.006; area under curve PNI vs. area under curve SII z test = 2.58, P =.009; area under curve PNI vs. area under curve NLR z test = 3.28, P =.001; respectively). Conclusions: Prognostic nutritional index was demonstrated as an independent predictor of major adverse cardiac events and all-cause mortality and a more powerful prognostic index than other novel inflammatory biomarkers in acute myocardial infarction patients treated with percutaneous coronary intervention.