Plasma copeptin, the COOH-terminal portion of pre-provasopressin and a surrogate marker of vasopressin, was shown to be positively associated with the decline in kidney function in the general population [11, 12, 17], and with the development and progression of DKD in type 1 and type 2 diabetes [10, 13, 16]. Here, AVP is linked to type 2 diabetes mellitus.