Association between Neutrophil-to-Lymphocyte Ratio and Glycemic Control in Patients with Type 2 Diabetes Mellitus

Open Access

Abstract

Background: Type 2 diabetes mellitus (T2DM) is associated with chronic low-grade inflammation that contributes to poor glycemic control and the development of diabetic complications. The neutrophil-to-lymphocyte ratio (NLR), derived from a routine complete blood count, has emerged as a simple and inexpensive marker of systemic inflammation. However, evidence regarding its relationship with glycemic control in Bangladeshi patients remains limited. Aim of the study: To evaluate the association between the neutrophil-to-lymphocyte ratio and glycemic control in patients with type 2 diabetes mellitus and to determine the diagnostic performance of NLR in identifying poor glycemic control. Methods & Materials: This hospital-based cross-sectional analytical study included 260 adult patients with T2DM. Clinical, anthropometric, and laboratory data were collected using a structured questionnaire and hospital records. Glycemic control was classified according to HbA1c levels as good (<7.0%) or poor (≥7.0%). NLR was calculated by dividing the absolute neutrophil count by the absolute lymphocyte count. Comparisons between groups were performed using the independent samples t-test and Chi-square test. Pearson's correlation analysis and receiver operating characteristic (ROC) curve analysis were conducted to evaluate the relationship and diagnostic performance of NLR. Result: The mean age of the participants was 56.8±9.4 years, and 56.5% were male. The mean NLR was 2.42±0.91. Patients with poor glycemic control had significantly higher neutrophil percentages and NLR values (2.70±0.87 vs. 1.89±0.46, p<0.001), while lymphocyte percentages were significantly lower (p<0.001). A significant association was observed between NLR categories and glycemic control (χ²=20.87, p<0.001). NLR demonstrated moderate positive correlations with fasting blood glucose (r=0.49), postprandial blood glucose (r=0.45), and HbA1c (r=0.58) (all p<0.001). ROC analysis identified an optimal NLR cutoff value of 2.25 for predicting poor glycemic control, with an AUC of 0.82 (95% CI: 0.74-0.89), sensitivity of 79.5%, specificity of 73.8%, and overall diagnostic accuracy of 77.5%. Conclusion: Elevated NLR was significantly associated with poor glycemic control and higher HbA1c levels in patients with T2DM. Given its simplicity, low cost, and availability from routine blood testing, NLR may serve as a useful adjunctive inflammatory marker for identifying patients at risk of poor glycemic control, particularly in resource-limited healthcare settings. Further prospective multicenter studies are warranted to validate its prognostic utility.