Tolvaptan treatment is associated with altered mineral metabolism parameters and increased bone mineral density in ADPKD patients

Background Autosomal dominant polycystic kidney disease (ADPKD) is characterized by a unique bone and mineral phenotype. The impact of tolvaptan treatment on mineral metabolism and bone mineral density (BMD) is unknown. Methods We conducted an analysis in the Bern ADPKD Registry, a prospective observational cohort study. Mineral metabolism parameters were measured at baseline and every 12 months thereafter. BMD was determined by dual-energy X-ray absorptiometry at baseline and after 3 years. Multivariable mixed-effects regression models were applied to assess changes in mineral metabolism parameters and BMD associated with tolvaptan treatment. Results A total of 189 participants (122 without and 67 with subsequent tolvaptan treatment) were included in the analysis. During follow-up, tolvaptan treatment was associated with increased BMD at the femoral neck {beta = 0.092 [95% confidence interval (CI) 0.001-0.183], P = .047}. In addition, tolvaptan treatment was associated with higher plasma magnesium [beta = 0.019 (95% CI 0.001-0.037), P = .037], bicarbonate [beta = 0.972 (95% CI 0.242-1.702), P = .009] and urine pH [beta = 0.214 (95% CI 0.056-0.372), P = .008] and lower parathyroid hormone [beta = -0.191 (95% CI -0.328 to -0.053), P = .006], 1,25(OH)D-3 [beta = -0.126 (95% CI -0.235 to -0.164), P = .024] and fractional urinary magnesium excretion [beta = -0.473 (95% CI -0.622 to -0.324), P Conclusions Chronic tolvaptan treatment is associated with increased femoral BMD and significant changes in both mineral metabolism and acid-base parameters in ADPKD patients.

Automated summary

In this study, chronic tolvaptan treatment was found to be associated with increased femoral bone mineral density (BMD) and significant changes in mineral metabolism and acid-base parameters in patients with ADPKD.