The relationship between serum copeptin levels, peritoneal transport parameters, and bioimpedance markers in pediatric patients undergoing peritoneal dialysis.

Background: The pathophysiology of hypervolemia in chronic kidney disease involves multiple mechanisms, with arginine vasopressin (AVP) playing a key role. Copeptin, a molecule located at the C-terminus of AVP, is often used as a substitute for AVP in clinical studies. In this study, we aimed to determine copeptin levels in pediatric patients with kidney failure treated by peritoneal dialysis (PD) and evaluate any possible correlation between bioimpedance parameters (BIA) and peritoneal transport parameters obtained from the peritoneal equalization test (PET).

Methods: The study included 37 patients undergoing PD as the patient group and 37 healthy children of the same gender and similar age as the control group. Patients' serum and peritoneal dialysis fluid copeptin levels and PET and BIA parameters were evaluated simultaneously, and possible relationships between them were examined.

Results: Serum copeptin levels in the patient group were found to be significantly higher than those in the control group (7.31 ng/ml vs. 2.55 ng/ml, p < 0.001). A negative correlation was observed between serum copeptin levels and age distribution in the control group. No relationship was found between serum copeptin levels and age or gender in the patient group. Furthermore, no significant correlation was found between serum copeptin levels and clearance values as well as transport parameters obtained by PET parameters and BIA parameters.

Conclusions: Serum copeptin levels are higher in patients on PD compared to the control group. However, no significant relationship is found between serum copeptin level and BIA or PET parameters. Further studies are needed to understand more about this subject.