AbstractBackgroundThe ratio of platelets to lymphocytes (PLR) can serve as a potential biomarker for predicting the prognosis of individuals with acute myocardial infarction (AMI).AimThe purpose of the research was to evaluate the in‐hospital outcomes of AMI patients and the predictive significance of PLR on major adverse cardiac events (MACE).MethodsA total of 799 AMI patients who had successful primary PCI within 12 h of the onset of chest pain were separated into low PLR (n= 511) and high PLR (n= 288) groups using a PLR cutoff value of 178. At admission, total white blood cell, neutrophil, lymphocyte, and platelet counts were assessed.ResultsIn patients with a high PLR group with PLR > 178, the incidence of MACE: heart rupture, acute heart failure, total adverse events, and mortality due to all events was considerably greater. In an analysis of the receiver operating characteristic curve, a high PLR > 178 accurately predicted adverse outcomes (73% specificity and 65% sensitivity). Age, hypertension, and PLR were found as independent predictors of adverse outcomes by multiple logistic regression.ConclusionsAMI patients with high PLR had poor hospital outcomes. These findings recommend PLR as an independent risk factor for hospital‐acquired complications, suggesting that inflammation and prothrombotic state may contribute to the poor prognosis of high PLR patients.