Association of systemic inflammatory indices and body mass index with diabetic macular edema in non-proliferative diabetic retinopathy

PURPOSE: To evaluate the association between systemic biomarkers and the presence of diabetic macular edema (DME) with non-proliferative diabetic retinopathy (NPDR), and to assess the discriminative ability of these markers for identifying DME. METHODS: A cross-sectional study was conducted among 80 patients with type 2 diabetes mellitus and NPDR. Participants were categorized into DME and non-DME groups based on spectral-domain optical coherence tomography (OCT), with a central macular thickness ≥ 300 μm defining DME. Hematological parameters were analyzed from complete blood counts. Statistical analysis was performed using SPSS 23.0. RESULTS: A total of 80 eyes (40 with DME and 40 without DME) were analyzed. Significant elevation of neutrophil counts was observed in the DME group (p = 0.006). Similarly, NLR and SII values were higher in the DME group (p = 0.075 and p = 0.048, respectively). The combined model of NLR, SII, and BMI showed moderate discriminatory ability (AUC 0.706, p = 0.002). NPDR severity was significantly associated with DME in the univariate and multivariate analyses of the initial model (OR 3.023, p = 0.049). This association lost statistical significance after adjustment for age and BMI. Systemic inflammatory markers (NLR, MLR, PLR, and SII) were not significantly associated with DME. CONCLUSIONS: SII and NLR demonstrated moderate discriminatory ability for identifying DME in patients with NPDR, particularly when integrated with the metabolic parameter BMI. These findings provide foundational evidence for the potential of using an accessible, cost-effective marker in diabetic retinal disease.