Comparison between copeptin and vasopressin in a population from the community and in people with chronic kidney disease

Abstract

Context: Vasopressin plays a central role in water homeostasis but it has also been recognized to be associated with adverse effects in several chronic diseases. Recently, copeptin has been increasingly used as a surrogate for vasopressin, as they are co-secreted, and copeptin is easier to measure. However, the relationship between plasma concentrations of copeptin (Pcop) and vasopressin (Pvp) has only been studied in relatively small numbers of selected people. Objective: This study sought to evaluate the relationship between Pvp and Pcop in a community-based population and in people with chronic kidney disease (CKD). Design, Setting, and Participants: Pvp, Pcop, and urinary osmolarity (Uosm) were compared in 500 participants of the DESIR study, and in 83 ambulatory people with CKD. Results: Median [interquartile range] of Pcop and Pvp in the DESIR study were 4.13 [3.58] pmol/L and 0.92 [1.93] pmol/L, respectively. Log-transformed Pcop and Pvp concentrations correlated significantly and positively (r = 0.686, P < .001) and they correlated inversely with estimated Uosm (P < .001, respectively. Conclusions: This study in a normal population, the largest ever with measurements of both peptides, shows that copeptin and vasopressin concentrations correlated well. But their relationship is distorted in CKD, suggesting that the peptide clearances differ when the renal function is impaired.