Monocyte/lymphocyte ratio as a risk factor of cardiovascular and all-cause mortality in coronary artery disease with low-density lipoprotein cholesterol levels below 1.4 mmol/L: A large longitudinal multicenter study.

Background and aims: The monocyte/lymphocyte ratio (MLR), an inflammatory marker, has an unclear relationship with the risk of residual inflammation in patients with coronary artery disease (CAD) and low-density lipoprotein cholesterol (LDL-C) below 1.4 mmol/L. This study aimed to assess the association between the MLR and cardiovascular and all-cause mortalities in these patients.

Methods: A total of 2747 patients diagnosed with CAD via coronary angiography (CAG) and presenting with LDL-C levels < 1.4 mmol/L were enrolled in this observational study conducted from January 2007 to December 2020. Patients were categorized into four groups based on the MLR quartiles. We used Kaplan-Meier analysis and Cox regression models to evaluate the relationship between baseline MLR and cardiovascular and all-cause mortalities.

Results: Among the 2747 participants followed up for a median duration of 6 years, there were 184 cardiovascular and 462 all-cause deaths. Elevated MLR levels were found to be associated with an increased risk of both cardiovascular and all-cause mortalities according to the Kaplan-Meier analysis. Multivariate Cox regression analysis demonstrated a significant association between higher MLR and an elevated risk of cardiovascular and all-cause mortality. Compared to the older group, with an increase in MLR levels, the younger group showed a higher hazard ratio for cardiovascular death. Similar results were obtained in the single-vessel disease group.

Conclusions: In patients with CAD and LDL-C levels < 1.4 mmol/L, MLR can serve as a risk factor for both cardiovascular and all-cause mortalities owing to the risk of residual inflammation.