Exploring the correlations between six serological inflammatory markers and different stages of type 2 diabetic retinopathy

To determine the correlations between six serological inflammatory markers, namely the systemic immune-inflammation index (SII), systemic inflammatory response index (SIRI), aggregate index of systemic inflammation (AISI), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and monocyte-to-lymphocyte ratio (MLR), and various stages of type 2 diabetic retinopathy (T2DR). Additionally, the diagnostic value of these markers in T2DR was evaluated. Clinical data were collected from a total of 397 patients with type 2 diabetes who visited the ophthalmology department at Mian Yang Central Hospital and the Affiliated Hospital of Southwest Medical University from January 2023 to December 2023. Based on the results of fundus photography, patients were categorized into a non-diabetic retinopathy group (NDR, n = 121), a non-proliferative diabetic retinopathy group (NPDR, n = 77), and a proliferative diabetic retinopathy group (PDR, n = 199). General patient information and systemic inflammatory markers, including the SII, SIRI, AIRI, NLR, PLR, and MLR, were compared among the groups, and their correlations with T2DR were analyzed. The SII values were found to be significantly higher in the PDR group compared to the NPDR group, which in turn were higher than those in the NDR group (P < 0.05). Similarly, the AISI values were significantly elevated in the PDR group compared to both the NPDR and NDR groups (P < 0.05). The SIRI and MLR values were significantly higher in the PDR group than in the NDR group (P < 0.05). Furthermore, the NLR and PLR values were significantly higher in the NPDR and PDR groups compared to the NDR group (P < 0.05). The Mantel‒Haenszel chi-square test revealed a significant linear trend between the SII and PLR and the incidence of PDR (P < 0.001), with the incidence of PDR increasing as the quartile levels of the SII and PLR increased. Multivariate logistic regression analysis indicated that, compared with NDR, a higher SII was found to be an independent risk factor for NPDR (ORSII = 1.002, p = 0.001) and PDR (ORSII = 1.002, P < 0.001). The ROC curve analysis suggested that the combined assessment of the six inflammatory indices had the highest accuracy in the evaluation of DR, with an area under the curve (AUC) of 0.69, a sensitivity of 54%, and a specificity of 75%. The results of this study indicate that the SII is an independent risk factor for T2DR. A close correlation was observed between the SII and PLR and the occurrence and progression of T2DR. The high accuracy of the combined diagnosis of T2DR via various serological inflammatory markers underscores their potential as early biological indicators for the diagnosis of T2DR.