Upacicalcet Preserves Albumin Levels in Patients on Hemodialysis with Secondary Hyperparathyroidism: A post hoc...

Parathyroid hormone (PTH) induces browning of adipose tissue, leading to increased resting energy expenditure and loss of adipose and muscle tissues in animal models of kidney failure. However, its clinical significance in humans remains unclear. This study aimed to investigate whether PTH-lowering therapy with upacicalcet, a novel injectable calcimimetic, affects serum albumin levels as a surrogate marker of protein-energy wasting in patients on hemodialysis with secondary hyperparathyroidism (SHPT).

This was a post hoc analysis of a phase 3, double-blind, placebo-controlled study of upacicalcet for the treatment of SHPT in patients on hemodialysis. Participants were randomized in a 2:1 ratio to receive either upacicalcet or placebo after each hemodialysis session for 24 weeks. Longitudinal changes in serum albumin levels were compared between groups using mixed-effects models for repeated measures. The rate of change (slope) in serum albumin over time was also estimated using a linear mixed-effects model.

A total of 99 patients in the upacicalcet group and 46 patients in the placebo group were included in the analysis. While serum albumin levels tended to decline in the placebo group, they remained relatively stable in the upacicalcet group, with a significant treatment-by-time interaction. In the linear mixed-effects model, the slope was less steep in the upacicalcet group than in the placebo group, although the between-group difference (0.09 g/dL per year; 95% CI, -0.04 to 0.23) did not reach statistical significance.

These findings raise the hypothesis that PTH suppression with upacicalcet mitigates the gradual decline in serum albumin levels over time. Further studies are warranted to investigate the long-term impact of PTH control on protein-energy wasting and related clinical outcomes.