Serum Globulin and Albumin-to-Globulin Ratio are Associated with Diabetic Kidney Disease but Not Diabetic Retinopathy in Type 2 Diabetes Mellitus Patients: A Cross-Sectional Study

Purpose: This study aimed to explore the association of globulin and albumin-to-globulin ratio (AGR) with diabetic kidney disease (DKD) and diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (T2DM). Methods: This study used data from the China National Diabetic Chronic Complications Study in Shaanxi Province. From April to May 2019, T2DM patients at disease surveillance sites in Shaanxi Province were investigated using a stratified multi-stage sampling method. The participants completed questionnaire surveys, anthropometric and blood pressure measurements, laboratory tests, and fundus photograph examinations. Multivariate Logistic regression and restricted cubic spline model were used to analyze the association of globulin and AGR with DKD and DR, and subgroup analysis was performed according to age, sex, and diabetes duration to test the stability of the results. Results: A total of 1494 T2DM patients were enrolled in this study, including 495 patients with DKD (33.1%) and 341 patients with DR (22.8%). After adjusting for all covariates, globulin and AGR were linearly associated with DKD. For every 1g/L increase in globulin level, the risk of DKD increased by 7% (OR=1.07, 95% CI=1.04, 1.10). For every 1 unit increase in AGR, the risk of DKD was reduced by 55% (OR=0.45, 95% CI=0.28, 0.72). Subgroup analysis showed that the association between globulin and DKD was consistent across all subgroups, and the association between AGR and DKD was consistent across subgroups of age and diabetes duration; however, only in males, higher AGR was associated with a reduced risk of DKD. No association was found between globulin and AGR with DR. Conclusion: Globulin is an independent risk factor and AGR is an independent protective factor for DKD. Screening for DKD should be performed in T2DM patients with high globulin and low AGR levels, especially in men.