Changes in serum copeptin in the early onset of type 2 diabetes

Copeptin (C-terminal fragment of pro-arginine vasopressin) levels change as fasting plasma glucose (FPG) and blood pressure change. To explore the clinical significance of changes in copeptin levels in development of type 2 diabetes mellitus (T2DM), we enrolled patients undergoing physical health examinations who met diagnostic criteria for prediabetes and T2DM. Subjects were divided into eight subgroups based on FPG levels and presence or absence of hypertension, including: a normal group (NGT), FPG < 5.6 mmol/L; prediabetes A, 5.6 mmol/L ≤ FPG < 6.1 mmol/L; prediabetes B, 6.1 mmol/L ≤ FPG < 7.0 mmol/L; and T2DM, FPG ≥ 7.0 mmol/L; participants were further into two subgroups by whether they had hypertension or not. Measures included biochemical indicators, fasting insulin (FINS), and copeptin. Copeptin levels in prediabetes A, prediabetes B, and T2DM groups increased significantly compared to NGT group ( P < 0.01). No significant differences were found in copeptin levels between normal blood pressure and hypertension subgroups in all four groups. Copeptin levels correlated positively with systolic blood pressure, glycosylated hemoglobin (HbA1c), FPG, FINS, and insulin resistance index (HOMA-IR; P < 0.05–0.001), and negatively with insulin secretion index ( P < 0.05–0.001). Stepwise regression analysis revealed that copeptin levels correlated independently with elevated HbA1c and aggravated HOMA-IR ( P < 0.001). Increase in copeptin levels may aggravate insulin resistance, finally leading to T2DM.