Predictors of One-Year Renal Function Decline in Type 2 Diabetes: Implications for Metabolic Target Management

Background: Early decline in kidney function is a major complication of type 2 diabetes mellitus (T2DM). The extent to which achievement of glycemic, blood pressure, lipid, and weight targets influences short-term renal trajectories remains insufficiently characterized. Methods: We conducted a retrospective analysis of 125 T2DM patients who had baseline and 1-year follow-up eGFR measurements at the Mongolia Japan Hospital of the MNUMS during 2023–2024. Clinical and metabolic control was categorized using standard thresholds. Renal outcomes were assessed using absolute 1-year eGFR change and the occurrence of ≥30% decline. Results: Mean eGFR declined from 91.2 ± 24.1 to 88.4 ± 25.5 mL/min/1.73 m2 over one year (mean change −3.77 ± 11.3 mL/min/1.73 m2); 7.2% experienced ≥30% decline. Individuals with pre-existing CKD showed significantly greater deterioration than those without (interaction p < 0.001). Poor glycemic control was consistently associated with greater decline: participants with HbA1c > 7.5% had a significant reduction and regression analyses showed an additional adjusted decline of −4.7 mL/min/1.73 m2 (p = 0.029) compared with those at target. Elevated blood pressure (>130/80 mmHg) was also associated with greater annual decline (adjusted β = −6.40, p = 0.024). Lower BMI (