Serum copeptin as a new biomarker in the early diagnosis of decline in renal function of type 2 diabetes mellitus patients.

OBJECTIVE This study aimed to investigate the correlation between serum copeptin and glomerular filtration rate (GFR) in type 2 diabetes mellitus (T2DM) patients and to investigate the role of serum copeptin in the diagnosis of early DN in T2DM patients. METHODS 120 T2DM inpatients were recruited and divided into 2 groups according to 24-h urine albumin excretion (UAE): normal UAE group (UAE<30 mg/24 h) and microalbuminuria group (30 mg/24 h≤UAE≤300 mg/24 h). RESULTS Decline in GFR was found in 6.1% of patients in normal UAE group and 26.4% in microalbuminuria group. However, serum copeptin was comparable between two groups. Serum copeptin was negatively related to GFR (r=-0.586, P<0.001). Multivariate logistic regression analysis showed, after adjustment for age and gender, the OR of copeptin, 24-h UAE was 1.234 (95% CI: 1.003-1.456) (P<0.05) and 1.068 (95% CI: 1.005-1.187) (P<0.05), respectively. Univariate analysis of ROC showed the sensitivity of copeptin and 24-h UAE was 78.9% and 63.2%, respectively and the specificity was 88.9% and 89.7%, respectively in the diagnosis of DN, but the area under ROC of copeptin in combination with 24-h UAE was 0.90 (95% CI: 0.82-0.99) with the sensitivity of 80.9% and specificity of 91.1%. CONCLUSION Serum copeptin is an independent risk factor of decline in renal function of T2DM patients. Copeptin in combination with 24-h UAE are helpful for the early diagnosis of DN. The causative relationship between serum copeptin and GFR is required to be further studied in long-term follow up.