Hematological Parameters and Glycemic Control in Type 2 Diabetes Mellitus: A Cross-Sectional Study with Focus on Neutrophil-to-lymphocyte Ratio

BACKGROUND: Inflammation plays a central role in the pathogenesis of Type 2 Diabetes Mellitus (T2DM). The neutrophil-to-lymphocyte ratio (NLR) has been proposed as a simple, cost-effective surrogate marker of systemic inflammation. However, its utility as a reliable indicator of glycemic control, measured by glycated hemoglobin (HbA1c), remains inconsistently demonstrated across populations. OBJECTIVES: The objective of the study was to evaluate the correlation between NLR and other hematological parameters with HbA1c levels in T2DM patients, and to assess the discriminatory utility of NLR across HbA1c strata. MATERIALS AND METHODS: A cross-sectional study was conducted on 134 patients with T2DM at AIIMS Hyderabad. Complete blood counts (CBC) with differential leukocyte counts were obtained. NLR was calculated from automated CBC. HbA1c was measured by ion-exchange high-performance liquid chromatography. Subjects were stratified into four HbA1c groups (<6.5%, 6.5%-8.0%, 8.1%-10.0%, and >10.0%). Statistical analyses included Mann-Whitney U-test, Kruskal-Wallis test, Chi-square test, and Spearman's rank correlation. RESULTS: The cohort comprised 53 males (39.6%) and 81 females (60.4%). Median HbA1c was 7.10% (interquartile range: 6.00-8.85). NLR showed no significant correlation with HbA1c (Spearman ρ = -0.016, P = 0.851). No significant difference in NLR was observed across four HbA1c strata (P = 0.889, Kruskal-Wallis). The proportion of subjects with NLR >3 did not differ significantly by glycemic category (P = 0.563, Chi-square). Monocyte count demonstrated a statistically significant inverse correlation with HbA1c (ρ = -0.181, P = 0.037). Females had significantly higher lymphocyte counts (P = 0.003) and total leukocyte counts (P = 0.008) compared to males. CONCLUSIONS: NLR does not reliably reflect glycemic control in T2DM patients in this Indian cohort. The inverse correlation of monocyte count with HbA1c warrants further investigation. NLR should be interpreted cautiously as a sole marker of glycemic severity.