The Monocyte-to-Lymphocyte Ratio Exhibits A Superior Prognostic Value in Patients with Newly Diagnosed Acute Coronary Syndrome

Abstract

Background: Chronic inflammation critically influences atherosclerotic progression and plaque destabilization. This investigation assessed and compared six lymphocyte-derived inflammatory indices (neutrophil-to-lymphocyte ratio (NLR), monocyte–lymphocyte ratio (MLR), platelet–lymphocyte ratio (PLR), systemic immune–inflammation index (SII), systemic inflammatory response index (SIRI), systemic immune–inflammation response index (SIIRI)) for predicting major adverse cardiovascular events (MACEs) in treatment-naïve acute coronary syndrome (ACS) patients undergoing coronary angiography. Methods: This study enrolled 1120 patients with newly diagnosed ACS, in which the occurrence of MACEs was monitored. The predictive capacities of the included lymphocyte-derived inflammatory indices were evaluated through receiver operator characteristic (ROC) curve analysis with optimal cutoffs, supplemented by Cox proportional hazards modeling. Results: A total of 265 MACEs (23.66%) were recorded during the 64.20 ± 23.05-month followup. Multivariate Cox analyses identified an elevated MLR (hazard ratio (HR) = 2.880, 95% confidence interval (CI) 1.280–6.470; p < 0.001) that was independently associated with the occurrence of MACEs in patients with newly diagnosed ACS. The ROC comparisons revealed a superior discriminative capacity of the MLR versus clinical factors, with an optimal MLR cutoff at 0.304 (sensitivity 61.1%; specificity 78.8%). Patients with a high MLR (≥0.304) exhibited a 3.5-fold increased risk of MACEs compared to those with a low MLR (46.96% vs. 13.29%; risk ratio = 1.635, 95% CI 1.475–1.812; p < 0.001); these data were corroborated by divergent Kaplan– Meier curves (log-rank p < 0.001). Meanwhile, subgroup analyses confirmed the prognostic consistency of the MLR across high-risk populations (age >60 years, diabetes, hypertension), with elevated MLR subgroups demonstrating uniformly higher rates of MACEs (all p < 0.001). Conclusions: MLR outperformed conventional parameters and five novel lymphocyte-based inflammatory indices in predicting MACEs in ACS patients; thus, the MLR can be established as a robust predictive biomarker. The clinical utility of the MLR extends to risk stratification across key patient subgroups, suggesting potential integration into routine cardiovascular risk assessment protocols.