The association of serum soluble Klotho levels and residual diuresis and overhydration in peritoneal dialysis patients.

Background: Klotho, originally identified as an anti-aging factor, is a transmembrane protein expressed in the kidney. It has been reported that Klotho deficiency could be associated with a loss of residual renal function and cardiovascular complications in peritoneal dialysis (PD) patients.
Objectives: The main aim of the study was to evaluate whether serum levels of Klotho correlate with residual diuresis and hydration status in PD patients.
Material and Methods: The cross-sectional study involved 57 PD patients ≥18 years of age who had been on PD ≥ 3 months. Serum Klotho was measured using high-sensitivity enzyme-linked immunosorbent assay (ELISA). Hydration status was assessed with bioimpedance analysis (BIA).
Results: Serum levels of soluble Klotho ranged from 100 pg/mL to 700 pg/mL. The patients were divided into 2 subgroups, with Klotho levels below and above the median (260 pg/mL). The data revealed a tendency for lower residual diuresis (1.3 ±1.0 L vs 1.8 ±0.8 L; p = 0.055) in patients with lower levels of Klotho in serum. Serum Klotho correlated negatively with overhydration according to BIA (r = -0.27; p = 0.044) and positively with residual diuresis (r = 0.26; p = 0.045).
Conclusions: Soluble Klotho correlates inversely with hydration status in BIA. Residual urine output, but not dialysis parameters, could be associated with the levels of serum soluble Klotho in PD patients.