Diabetic retinopathy (DR) is one of the main causes of blindness worldwide, but an effective screening is challenging due to limited available retina specialists. Finding novel biomarkers could help clinical decision in prioritizing ophthalmological consultation in patients at risk of developing severe DR. This study aims to investigate the association between neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and the presence and severity of DR in patients with T2DM. A retrospective study was performed on 90 patients with T2DM admitted in the Ophthalmology Clinic, Emergency University Hospital Bucharest in Bucharest, Romania, between March 2022 and March 2023, for routine cataract surgery. The cases were divided into three groups according to the severity of DR: no DR (noDR), non-proliferative diabetic retinopathy (NPDR), and proliferative DR (PDR) groups. NLR values raised significantly in the PDR group, no DR group (p = 0.003), and NPDR group (p = 0.026), while PLR values did not differ statistically significant among the groups (p = 0.059). No difference in terms of age, sex, HbA1C, and comorbidities were observed. In the multivariate analysis, the NLR (OR = 2.01, [1.29; 3.14], p = 0.0019) and diabetic nephropathy (OR = 3.84, [1.23; 11.98], p = 0.0203) were associated with higher rates of PDR. NLR may be a promising tool in the risk stratification of T2DM patients with DR.

Diabetic retinopathy is one of the major causes of visual impairment and blindness in adult population. The pathology is complex, the metabolic changes induced by the hyperglycemic environment leading to neurodegeneration, microvascular damage, with secondary ischemic and inflammatory changes in the retina. This review aims to update the literature data related to the role of inflammation in the onset and progression of diabetic retinopathy. Thus, the molecular and biochemical mechanisms triggered by excess glucose increase the expression of genes involved in inflammatory processes, which leads to the synthesis of inflammatory cytokines such as Il1, Il6, TNF alpha as well as complement activation. Furthermore, recent evidence has demonstrated that both systemic and ocular prolonged inflammation are correlated with the progression of diabetic retinopathy. In conclusion, preventing and/or reducing the progression of diabetic retinopathy requires both rigorous glycemic control in diabetic patients and targeted interference of the specific inflammatory pathways involved.

Background: Non-proliferative diabetic retinopathy (NPDR) is a common microvascular complication of type 2 diabetes mellitus (T2DM) associated with chronic inflammation, metabolic dysregulation, and multiple interacting systemic factors. This study evaluated the associations of inflammatory biomarkers, serum 25-hydroxyvitamin D [25(OH)D], electrolyte homeostasis, and lipid-derived indices with NPDR. Methods: In this cross-sectional study with prospective recruitment, 98 patients with T2DM were classified into NPDR (n = 55) and non-DR (n = 43) groups. Clinical characteristics, hematological inflammatory indices, serum interleukin-6 (IL-6), C-reactive protein (CRP), 25(OH)D, electrolyte concentrations, lipid profile, and derived biomarkers—including the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), systemic immune–inflammation index (SII), LDL-C/HDL-C ratio, and calculated serum osmolarity—were compared. Receiver operating characteristic (ROC) analysis and multivariable logistic regression were performed to assess discriminatory performance and independent associations with NPDR. Results: Patients with NPDR had significantly lower serum 25(OH)D concentrations than the non-DR group (16.6 ± 7.5 vs. 21.0 ± 5.2 ng/mL, p < 0.001). Serum IL-6 levels (4.2 ± 3.1 vs. 2.8 ± 1.4 pg/mL, p = 0.047), NLR (p = 0.043), LDL-C/HDL-C ratio (p = 0.031), and calculated serum osmolarity (p = 0.033) were significantly higher, whereas lymphocyte count and the lymphocyte-to-monocyte ratio were significantly lower. Among individual biomarkers, serum 25(OH)D showed the best discriminatory performance (AUC = 0.712). A multivariable model including insulin therapy, IL-6, serum 25(OH)D, and the LDL-C/HDL-C ratio demonstrated good discrimination (AUC = 0.813), with 81.8% sensitivity and 81.4% specificity. Bootstrap validation supported the stability of the model. Conclusions: NPDR was associated with lower serum 25(OH)D concentrations, systemic inflammation, and a less favorable LDL-C/HDL-C ratio. A multivariable model integrating inflammatory, metabolic, and nutritional biomarkers showed better discriminatory performance than individual biomarkers. The association between insulin therapy and NPDR likely reflects greater diabetes severity rather than a direct effect of insulin. These findings are exploratory, and prospective studies in larger independent cohorts are needed to determine whether these biomarkers improve risk stratification beyond established clinical factors.