Objective To investigate the association between neutrophil to lymphocyte ratio (NLR) andestimated glomerular filtration rate (eGFR) in patients with diabetes using large-scale data.

Methods Across-sectional analysis was conducted using data from diabetic patients in the National Health and Nutrition Examination Survey database from 2009 to 2014. Differences in NLR between patients with and without chronickidney disease (CKD) were compared. Pearson correlation analysis and multiple linear regression models wereapplied to assess the relationship between NLR and eGFR.

Results A total of 857 diabetic patients were included, with 190 (22.2%) having CKD and 667 (77.8%) without CKD. NLR was significantly higher in patients with CKD compared to those without CKD (2.94±1.69 vs.2.36±1.98, P < 0.001), while eGFR wassignificantly lower(43.54± 12.79) mL/(min· 1.73 m²) vs.(92.50± 18.20) mL/(min· 1.73 m²), P < 0.001. Quartile analysis revealed a progressive decline in eGFR with increasing NLRQ1:(87.05 ±24.93) mL/(min· 1.73 m²);Q2:(83.68 ± 24.98) mL/(min· 1.73 m²);Q3:(83.10 ± 26.26) mL/(min· 1.73 m²);Q4:(72.55 ± 28.15) mL/(min · 1.73 m²);P < 0.001. Pearson correlation analysisshowed a weak negative relationship between NLR and eGFR (r=-0.15, P < 0.001). After adjusting for confounders, multiple linear regression demonstrated an independent negative association between NLR and eGFR(OR=0.403, 95% CI: 0.210-0.772, P=0.006).

Conclusions NLR is independently negatively associatedwith eGFR in diabetic patients, demonstrating potential clinical value as an indicator of kidney function declineand CKD risk in this population.