Prognostic nutritional index as a novel marker for diabetic retinopathy in individuals with type 2 diabetes mellitus

PURPOSE: In recent years, the prognostic nutritional index (PNI), an easily obtainable nutritional inflammatory marker, has been introduced as an independent prognostic indicator for various types of cancers and cardiovascular diseases. However, its clinical importance in the area of ophthalmology is not well known yet. We aimed to elucidate the association between the PNI and the occurrence of diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (T2DM). METHODS: In this cross-sectional study, the PNI was applied to 128 consecutive patients with T2DM. The relationship between the PNI and the occurrence of DR was examined. PNI was calculated as 10× (serum albumin) + 0.005 × (total lymphocyte count). The risk factors for DR were evaluated using multivariate logistic regression analysis. A receiver operating characteristic (ROC) curve analysis of PNI for predicting DR was performed. RESULTS: Patients with DR had significantly lower levels of PNI than those without DR (41.20 ± 4.81 and 44.49 ± 3.10, respectively,P< 0.001). Multivariate regression analysis indicated that PNI, together with the duration of diabetes and creatinine, was an independent factor for DR occurrence (odds ratio, 0.885; 95% confidence interval: 0.735–0.971;P= 0.017). ROC curve analysis revealed that the best cutoff value of PNI was 43 (area under the curve: 0.713; sensitivity: 74%; specificity: 64%). CONCLUSION: A lower PNI value is common among T2DM patients with DR and is strongly associated with the occurrence of DR. The PNI might be a useful biomarker for identifying DR to improve the risk stratification and management of T2DM patients.