Prognostic impact of monocyte-to-lymphocyte ratio in coronary heart disease: a systematic review and meta-analysis

Objective Inflammatory biomarkers are novel tools to assess the prognosis of different cardiovascular diseases. We evaluated the impact of the monocyte-to-lymphocyte ratio (MLR) on clinical outcomes in patients with coronary heart disease (CHD). Methods We systematically screened English-language articles in PubMed, Scopus, and Web of Science to 31 August 2022. Relevant articles reporting the MLR and its association with clinical outcomes (major adverse cardiovascular events (MACE), coronary artery disease (CAD) severity, mortality, cardiac rupture, subclinical CAD, acute coronary syndrome (ACS) prediction, thin-cap fibroatheroma, no-reflow phenomenon, MLR-related differences in percutaneous coronary intervention, heart failure hospitalization, and depression) in patients with CHD were collected for further analysis. Results Nineteen articles were selected. The mean MLR was 0.34. A higher MLR was significantly associated with an increased risk of MACE among patients with CHD. The MLR was an independent predictor of MACE in patients with ACS. No significant association was found for CAD severity. A complementary analysis was not performed because of few studies focusing on the other predefined endpoints. Conclusions The MLR is a simple and widely available tool to predict MACE in patients with CHD. This biomarker can be utilized in emergency settings to prioritize high-risk patients and optimize therapeutic interventions.