Correlation between the neutrophil-to-lymphocyte ratio with the severity of new-onset coronary artery disease in various glucose metabolic states: a retrospective study

Inflammation plays a crucial role in promoting coronary artery disease (CAD). The Neutrophil-to-Lymphocyte Ratio (NLR) is a novel comprehensive indicator reflecting systemic inflammation, with previous studies indicating its association with cardiovascular events and mortality. However, the correlation between NLR and the severity of new-onset CAD at different glucose metabolism has not been explored. This study aims to determine the relationship between NLR and the new-onset of CAD and severity of coronary artery lesions in patients with varying levels of glucose metabolism. In this retrospective study, 1689 patients with acute coronary syndromes who underwent coronary angiography were included. Based on patients’ medical history and fasting blood glucose levels, subjects’ glucose metabolism status was categorized as normal glucose regulation (NGR), pre-diabetes mellitus (Pre-DM), and diabetes mellitus (DM). The severity of CAD was assessed using the Gensini score (GS), and subjects were divided into three groups based on GS tertiles. The relationship between NLR and CAD was validated through logistic regression analysis. The Restricted Cubic Spline (RCS) was employed to determine the quantitative relationship between NLR and GS in different populations. Logistic regression analysis revealed a significant association between elevated NLR levels and increased odds ratio (OR) of CAD in the fully adjusted model, regardless of the glucose metabolic state. Specifically, in individuals with NGR, the OR was 1.13[95%CI: (1.07, 1.20), P<0.001]; in Pre-DM, the OR was 1.11[95%CI: (1.01, 1.21), P<0.001] and in DM, the OR was 1.08[95%CI: (1.02, 1.15), P = 0.009]. It is noteworthy that there was no statistical correlation between NLR and the severity of CAD in the DM population, while an association was observed in non-diabetic patients. The RCS analysis confirmed a nonlinear relationship between NLR and the GS in total population and NGR group (P for nonlinear < 0.05), with distinct inflection points, which was not observed in the Pre-DM and DM groups. There is a correlation between NLR and the occurrence of new-onset CAD, and more importantly, NLR reflects the severity of CAD to some extent, and this correlation is more common in patients with NGR and Pre-DM; however, in patients with DM, NLR does not accurately reflect the extent of coronary artery disease.