The Neutrophil-to-Lymphocyte Ratio Predicts Cardiovascular Outcomes in Patients With Diabetes: A Systematic Review and Meta-Analysis

The neutrophil-to-lymphocyte ratio (NLR) has been found as a potential biomarker for acute inflammation and the prognosis of different diseases. Here, we provided a meta-analysis of studies evaluating the association of NLR with cardiovascular outcomes among patients with diabetes. We searched PubMed, Scopus, and Web of Science databases from inception to April 06, 2024, to include papers based on eligible criteria. The outcomes of interest were all-cause mortality, cardiovascular mortality, major adverse cardiovascular events, myocardial infarction, and stroke. The pooled risk ratio (RR) and corresponding 95% confidence intervals (CI) were reported. Meta-analysis was performed using StataMP 14.0. A total of 15 studies involving 407,512 participants were included. Meta-analysis revealed that both categorical and continuous NLRs are linked to increased risk of all-cause mortality (RR = 1.68; 95% CI, 1.49-1.88; P < 0.001 and RR = 1.03; 95% CI, 1.03-1.03; P < 0.001, respectively) and cardiovascular mortality (RR = 2.04; 95% CI, 1.58-2.63; P < 0.001 and RR = 1.25; 95% CI, 1.19-1.32; P < 0.001, respectively) in patients with diabetes. However, NLR was not associated with the risk of major adverse cardiovascular events, myocardial infarction, and stroke in patients with diabetes. Subgroup analysis revealed sample size as the main source of the heterogeneity found between studies. The findings suggest NLR as a prognostic marker for mortality outcomes in patients with diabetes, providing clinicians with a noninvasive and readily available indicator for risk assessment and patient management.