Predictive efficacy assessment of serum β2-microglobulin combined with urinary albumin-to-creatinine ratio for renal function deterioration in type 2 diabetic patients with kidney disease.

OBJECTIVE: To assess the value of serum β2-microglobulin (β2MG) and urinary albumin-to-creatinine ratio (UACR) in predicting short-term renal function decline in patients with type 2 diabetic kidney disease (DKD). METHODS: We retrospectively analyzed 356 patients with diabetic kidney disease who received standard care combined with SGLT-2 inhibitors and were followed for six months at Baoji People's Hospital and Hanzhong People's Hospital. Renal deterioration was defined as a ≥30% decline in estimated glomerular filtration rate (eGFR). Clinical and biochemical indicators were assessed using multivariate logistic regression. Model discrimination and calibration were examined through ROC analysis, Akaike information criterion (AIC), and DeLong testing. An additional cohort of 145 patients was used for external validation. RESULTS: Among all participants, 78 (21.9%) experienced renal function decline. Seven variables were independently associated with deterioration: contrast agent exposure, systolic blood pressure, fasting glucose, HbA1c, cystatin C, UACR, and β2-microglobulin. UACR had the strongest individual performance (AUC=0.891; cutoff =174.8 mg/g). The complete seven-factor model demonstrated excellent discrimination (AUC=0.994) and maintained high accuracy in external validation (AUC=0.949; sensitivity 90.6%; specificity 93.8%). CONCLUSION: β2-microglobulin and UACR emerged as robust early predictors of renal deterioration in DKD. A combined model integrating these and related indicators provides precise short-term risk assessment and may assist clinicians in tailoring management strategies.