A Clinical Epidemiological Analysis of Prognostic Nutritional Index Associated with Diabetic Retinopathy

Prognostic nutritional index (PNI) is an effective tool to evaluate the nutritional conditions and predict prognosis, but clinical data are limited for the use of PNI in diabetic retinopathy (DR). This study aimed to investigate the relationship of PNI with the prevalence and severity of DR in patients with type 2 diabetes mellitus (T2DM).

This cross-sectional analysis enrolled 1023 individuals with T2DM hospitalized between 2017-2020. PNI was calculated as 10 × serum albumin (g/l) + 0.005 × total lymphocyte count (cells/mL). DR severity was categorized as no, nonproliferative, and vision-threatened DR (VTDR) according to the modified Airlie House classification. Multivariate-adjusted odds ratio (OR) with 95% confidence interval (CI) for the prevalent DR in the top (Q4) compared with the bottom quartile (Q1) of PNI levels were estimated by using logistic regression analyses.

PNI levels were significantly lower in individuals with VTDR than those with no and nonproliferative DR (both P < 0.001), and the proportions of individuals with DR were significantly decreased in the top quartile compared with the bottom quartile of PNI levels (P < 0.001). After adjustments for age, gender, DM duration, obesity-related risk factors and clinical biochemical parameters, the higher levels of PNI were significantly associated with a lower prevalence of DR (Q4 vs Q1: OR = 0.402, 95% CI: 0.250-0.649, P < 0.001), with a 5.9% reduction in the prevalence of DR for a per-unit increment in the levels of PNI (OR = 0.941, 95% CI: 0.911-0.972, P < 0.001). The association of PNI and obesity-related indexes (body mass index and waist circumference) with the severity of DR was independent of each other (P<0.001).

PNI was inversely and independently associated with the severity and prevalence of DR, which suggested that PNI could likely be used to predict DR prognosis in clinical practice.