Abstract
BACKGROUND: Diabetic retinopathy (DR), a major complication of type 2 diabetes mellitus (T2DM), remains a growing global health concern. This study aimed to evaluate the relationship between systemic inflammatory markers and both the presence and severity of DR. Special attention was given to the pan-immune-inflammation value (PIV), a novel composite index of immune response, whose association with DR remains underexplored. MATERIALS AND METHODS: A prospective cross-sectional study was conducted involving 310 patients with T2DM, grouped based on the International Clinical Diabetic Retinopathy Disease Severity Scale (ICDR): no DR (NDR, n = 100), non-proliferative DR (NPDR, n = 100), and proliferative DR (PDR, n = 110). Clinical and laboratory data-including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), neutrophil-to-HDL cholesterol ratio (NHR), systemic immune-inflammation index (SII), and PIV-were analyzed. Statistical methods included ANOVA, Kruskal-Wallis, and receiver operating characteristic (ROC) analyses. RESULTS: PDR patients had significantly elevated NLR (p = 0.005), MLR (p < 0.001), NHR (p = 0.016), C-reactive protein-to-albumin ratio (CAR) (p < 0.001), and PIV (p = 0.002) levels. In NPDR, PLR (p = 0.012) and SII (p = 0.005) were significantly higher than in the other groups. NLR showed the highest predictive performance in ROC analysis (sensitivity: 84.8%), followed by SII (78.1%), PLR (76.2%), and PIV (53.3%). CONCLUSION: Among patients with T2DM, inflammatory markers-particularly NLR, PLR, SII, and PIV-suggested potential relevance in identifying DR and its progression. PLR and SII may have utility in the early identification of NPDR, while PIV appears to be a potentially valuable inflammatory marker. These cost-effective and easily accessible indices may contribute to the screening and monitoring of DR in clinical settings.