Abstract:

ABSTRACT Objective: To investigate the histological injury of type 2 diabetic patients with normoalbuminuria, and to determine the risk factors for predicting the progression to microalbuminuria and eGFR decline. Methodology: Forty one type 2 diabetic patients with normoalbuminuria and serum creatinine ≤109.62mol/L who received renal biopsy were enrolled in this study. Clinical indicators and pathological indicators were recorded. The definition of progression of albuminuria was urinary albumin excretion≥ 30mg/24h during the follow-up. eGFR decline was defined as a rate of eGFR loss of ≥3.3% per year. Results: The renal histological injuries such as glomerular enlargement, mesangial proliferation and thickening of GBM were found in all of 41 diabetic patients with normoalbuminuria, which have no significant difference with the 39 microalbuminuria diabetic patients. The slit diaphragm frequency was higher in NOR-UAE group than MAU group (1.18±0.39 vs 0.83±0.35 slits/μm，P<0.001). 10 patients progressed to microalbuminuria during the follow-up, the glomerular volume and GBM width were larger in the progressive group than that in non-progressive group. Multivariate COX regression analysis indicated that greater width of GBM and larger glomerular volume were independent predictors of progression to microalbuminuria. eGFR was declined ≥3.3%/year in 5 patients. Multivariate Logistic regression analysis indicated that lower baseline eGFR was the independent predictor of eGFR decline (HR 0.774（0.615-0.973）, P=0.028). Conclusion: Histological manifestations of DN have been existed in type 2 diabetic patients with normoalbuminuria. Greater width of GBM and larger glomrular volume were independent predictors of progression to microalbuminuria, and lower baseline eGFR was the independent predictor of eGFR decline.

Key words: diabetes mellitus, albuminuria , pathology