Objective: Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease. Metrnl is a secreted protein that plays an important role in kidney disease. The aim of this study was to investigate DKD-related factors and the correlation between serum Metrnl levels and the severity of DKD.
Methods: Ninety-six type 2 diabetes mellitus (T2DM) patients and 45 DKD patients were included in the study. A range of parameters were measured simultaneously, including waist-to-hip ratio (WHR), body mass index (BMI), urinary albumin/creatinine ratio (UACR), monocyte–lymphocyte ratio (MLR), albumin/globulin (A/G), liver and kidney function, blood lipid profile, islet function, and others. Subsequently, the related factors and predictive significance of DKD were identified. The correlation between the relevant factors of DKD and serum Metrnl levels with DKD was evaluated.
Results: The duration of the disease (OR: 1.12, 95% CI: 1.01– 1.24, P=0.031), hypertension (OR: 4.86, 95% CI: 1.16– 20.49, P=0.031), fasting blood glucose (OR: 1.23, 95% CI: 1.03– 1.48, P=0.025), WHR (OR: 2.53, 95% CI: 1.03– 6.22, P=0.044), and MLR (OR: 1.91, 95% CI: 1.18– 3.08, P=0.008) are independent risk factors for DKD (P < 0.05). Conversely, A/G (OR: 0.13, 95% CI: 0.02– 0.76, P=0.024) and Metrnl (OR: 0.99, 95% CI: 0.98– 1.00, P=0.001) have been identified as protective factors against DKD. Furthermore, the level of Metrnl was negatively correlated with the severity of DKD (r_s=− 0.447, P< 0.001). The area under receiver operating characteristic (ROC) curves for the diagnostic accuracy of Metrnl for DKD is 0.765 (95% CI: 0.686– 0.844).
Conclusion: The duration of the disease, hypertension, fasting blood glucose, WHR, and MLR are major risk factors for DKD. Metrnl and A/G are protective factors for DKD. Serum Metrnl concentrations are inversely correlated with DKD severity.

Keywords: diabetic kidney disease, urinary albumin/creatinine ratio, Metrnl, albumin/globulin