Prognostic value of the monocyte-to-high-density lipoprotein-cholesterol ratio in acute coronary syndrome patients: A systematic review and meta-analysis

Background: Globally, diseases of the cardiovascular system stand as principal contributors to mortality and are expected to show an upward trajectory. The occurrence of acute coronary syndrome (ACS) has been linked to underlying inflammatory processes. The monocyte-to-high-density lipoprotein-cholesterol ratio (MHR) has garnered significant attention as a prognostic biomarker, encapsulating the synergistic roles of inflammation and lipid metabolism in the pathophysiology of cardiovascular diseases, including ACS. Aims: This meta-analysis examines the prognostic MHR ratio in ACS patients. Methods: We systematically searched PubMed, Embase, Scopus, Web of Science, and the Cochrane Library databases to identify the relevant meta-analyses published before February 26, 2024. The findings were aggregated into risk ratios with 95% confidence intervals. Results: Eleven studies, with 7421 patients, were included. Low MHR levels compared to high MHR levels were associated with statistically significantly lower in-hospital mortality (0.9% vs. 5.5%; respectively; P <0.001), 3-month mortality (4.4% vs. 11.2%; P = 0.02), 6-month follow-up mortality (4.0% vs. 10.2%; P = 0.03), 1-year mortality (4.2% vs. 10.2%; P <0.001), as well as long-term follow-up mortality (7.5% vs. 13.7%; P <0.001). Conclusions: MHR has both good predictive properties for mortality and major adverse cardiovascular events (short- and long-term). Data indicate that MHR may improve in-hospital and long-term cardiovascular risk prediction. It may, therefore, be an effective tool for risk re-estimation and selection of patients for whom intensive lipid-lowering treatment may be particularly useful.