Cholesterol-modified prognostic nutritional index: a novel nutritional biomarker for prevalent diabetic retinopathy in patients with type 2 diabetes mellitus

Abstract

To investigate the association and dose–response relationship between the cholesterol-modified prognostic nutritional index (CPNI) and diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (T2DM), and to evaluate its utility in identifying prevalent DR. In this retrospective cross-sectional study, 1,750 patients with T2DM (654 with DR and 1,096 without DR) were enrolled. Multivariable logistic regression, subgroup, trend, and restricted cubic spline analyses were performed to evaluate the association between CPNI and prevalent DR. A nomogram for identifying prevalent DR was developed using variables selected by least absolute shrinkage and selection operator regression and multivariable logistic regression. Model performance was evaluated using discrimination, calibration, bootstrap internal validation, incremental predictive performance, and decision curve analysis. Higher CPNI levels were independently associated with prevalent DR (OR = 1.024, 95% CI: 1.012–1.037, p  < 0.001). A significant positive linear dose–response relationship between CPNI and prevalent DR was observed, with no evidence of nonlinearity in the RCS analyses. Subgroup analyses demonstrated stronger associations among participants with BMI < 25 kg/m 2 and those with a history of alcohol consumption. A nomogram incorporating disease duration, using insulin, neutrophil, ALT, HbA1c, and CPNI demonstrated acceptable discrimination (apparent AUC = 0.724; optimism-corrected AUC = 0.715), good calibration, and favorable clinical utility. CPNI was independently and positively associated with prevalent DR in patients with T2DM and exhibited a linear dose–response relationship. A nomogram incorporating CPNI demonstrated acceptable performance for identifying prevalent DR.