Risk Factors for Elevated Renal Glucose Threshold in Patients with CKD and Their Value for Treatment of CKD: A Cross-Sectional Study

Background: This study aimed to investigate renal threshold for glucose (RTG) levels and their risk factors in patients with chronic kidney disease (CKD). Methods: A cross-sectional study was conducted, enrolling 130 patients with CKD admitted to Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, and Zhongxiang People's Hospital between September 2021 and March 2023. Patients were stratified with CKD according to the CKD staging diagnostic criteria based on KDIGO guidelines, and RTG levels were measured. Participants were categorized into three groups: high RTG (>10.08 mmol/L), normal RTG (8.88–10.08 mmol/L), and low RTG (<8.88 mmol/L). Clinical and laboratory data were collected and compared across groups. Spearman correlation and logistic regression analyses were performed to identify the risk factors for elevated RTG. Results: In CKD patients with stage 3-4, the RTG increases with progressive renal impairment. However, as CKD advances to stages 3–5, more severe renal impairment is associated with a reduction in RTG. The stratification of RTG levels revealed that patients with high RTG levels were older, had significantly elevated BMI, fasting plasma glucose and total cholesterol, but with lower serum sodium levels. Correlation analyses demonstrated positive associations between RTG and metabolic parameters (blood glucose and lipid profiles), while revealing a significant negative relationship with serum sodium. The RTG levels showed particularly strong positive correlation with serum creatinine in early-stage CKD (p＜0.0001). Multivariate regression analysis delineated stage-specific predictors of RTG: BMI emerged as the principal risker for elevated RTG in early-stage disease, whereas RTG in advanced stages were predominantly influenced by age, blood glucose, and cholesterol levels , with serum sodium consistently exhibiting a consistent negative correlation with RTG levels across all stages. The severity of glomerulosclerosis maintained a significant positive correlation with RTG levels (P=0.028). Conclusion: Elevated RTG in CKD patients is closely associated with metabolic abnormalities and renal impairment. When patients with CKD present high BMI, older age, higher cholesterol and hyponatremia, it indicates these patients have an elevated RTG that requires targeted intervention.