Combined predictive value of neutrophil-lymphocyte ratio and platelet-lymphocyte ratio for risk of in-hospital mortality in patients with acute myocardial infarction: a propensity score-based retrospective cohort study postprint

Abstract: Background　 Studies have shown that neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) have important predictive value for cardiovascular diseases. No studies have investigated whether the combination of NLR and PLR can enhance its predictive value for in-hospital mortality in patients with acute myocardial infarction. Objective　　To investigate whether the combined predictive model (NLR + PLR) constructed based on logistic regression algorithm can improve the predictive value of in-hospital mortality risk in patients with AMI. Methods A single-center, regression cohort study of 3246 AMI patients with complete medical history admitted to the Department of Cardiology of the Second Affiliated Hospital of Dalian Medical University from December 2015 to December 2021 was conducted. The outcome was defined as all-cause mortality during hospitalization. Results　　(1) The patients who died during hospitalization were matched according to the ratio of 1:1 based on Propensity Score Matching (PSM). All patients who died were successfully matched, resulting in 115 pairs of patients. There was no significant difference between the groups of patients who died during hospitalization (N = 115) and those who did not (N = 115) on the 20 independent variables already included in the matching (P > 0.05). (2) NLR + PLR (NLR combined with PLR) was superior to NLR (AUC = 0.754) and PLR (AUC = 0.731) alone in predicting the risk of in-hospital mortality, with a significant difference in the area under the ROC curve (P = 0.037, P < 0.001, respectively). (3) the optimal cut-off value for NLR + PLR was 0.5491 (Youden index = 0.4087, sensitivity = 85.22%, specificity = 55.65%).Cox regression analysis showed that patients with NLR + PLR > 0.549 had a higher risk of death (HR 2.936; 95% CI 1.963 – 4.392; P < 0.001) than patients with NLR + PLR ≤ 0.549. (4) NLR + PLR had a higher predictive ability for the risk of in-hospital mortality in patients with ST-segment elevation myocardial infarction (STEMI) (AUC = 0.797) than in patients with non-ST-segment elevation myocardial infarction (NSTEMI) (AUC = 0.739). Conclusions　　In this retrospective cohort study, we adjusted for multiple risk factors affecting in-hospital mortality in hospitalized AMI patients by propensity score matching.Our findings suggest that NLR combined with PLR can more accurately predict in-hospital mortality risk in AMI patients, especially in STEMI patients, than NLR or PLR alone.