Abstract:

Objective To investigate the roles of glycated hemoglobin A_1c（HbA_1c）,serum C-peptide and urinary N-acetyl-beta-D-glucosaminidase（NAG） determinations for the diagnosis of early renal damage in type 2 diabetes mellitus（T2DM）. Methods A total of 236 T2DM patients and 62 healthy subjects（healthy control group） were enrolled. According to urinary albumin to creatinine ratio（ACR）,the T2DM patients were classified into T2DM with early renal damage group（124 cases） and simple T2DM group（112 cases）. The levels of HbA_1c,serum C-peptide and urinary NAG in the 3 groups were determined. Receiver operating characteristic（ROC） curve was used to assess the diagnostic efficiency of each index. Results The levels of HbA_1c and urinary NAG in healthy control group,simple T2DM group and T2DM with early renal damage group were increased in turn,and the levels of serum C-peptide was decreased in turn（P<0.05）. The area under ROC curve（AUC） of the combined determination of HbA_1c,serum C-peptide and urinary NAG for the diagnosis of early renal damage in T2DM was 0.936,which was higher than those of individual determinations（AUC were 0.860,0.883 and 0.709）and two-index combined determinations（AUC were 0.876 for HbA_1c+urinary NAG,0.919 for HbA_1c+serum C-peptide and 0.902 for urinary NAG+serum C-peptide）. The sensitivity and specificity of the combined determination of 3 indices were 91.9% and 85.7%,respectively. Conclusions HbA_1c,serum C-peptide and urinary NAG are sensitive for the diagnosis of early renal damage in T2DM,and the combined determination of 3 indices may improve the determination rate of early renal damage.

Key words: Glycated hemoglobin A1c, C-peptide, N-acetyl-beta-D-glucosaminidase, Type 2 diabetes mellitus, Diabetic nephropathy