Relationship between BNP level and renal function in diabetic nephropathy with microalbuminuria

Aims: We examined the relationship between the brain natriuretic peptide (BNP) level and renal function in diabetic nephropathy with microalbuminuria. Methods: The subjects were 97 Japanese type 2 diabetes mellitus outpatients with microalbuminuria. Associations between the annual rate of decline in estimated glomerular filtration rate (eGFR) and various metabolic parameters at baseline (BMI, systolic blood pressure, HbA1c, LDL cholesterol, urine albumin-creatinine ratio, BNP and eGFR) were examined. Results: Among the baseline factors, eGFR and BNP had significant associations with the annual rate of decline in eGFR in Pearson correlation analysis (r = 0.295, p = 0.003; r = 0.223, p = 0.028, respectively). Multiple linear regression analysis also showed the significance of baseline eGFR and BNP as independent predictors of renal function (β = 0.340, p = 0.001; β = 0.278, p = 0.005, respectively). In multivariate logistic regression analysis, eGFR and BNP were independently associated with the risk of a decline in GFR (p = 0.003, p = 0.011, respectively). ROC curve analysis showed a cutoff value of BNP is 17.0 pg/mL for predicting a decline in GFR. Conclusions: The BNP level at baseline is an independent predictor of the annual rate of decline in eGFR. Therefore, monitoring of BNP can play an important role in management of diabetic nephropathy.