Immediate drop of urine osmolality upon tolvaptan initiation predicts impact on renal prognosis in patients with ADPKD

• Published in: Nephrology, dialysis, transplantation dialysis, transplantation, 2024-05, Vol.39 (6), p.1008-1015
• Main Authors: Akihisa, Taro, Kataoka, Hiroshi, Makabe, Shiho, Manabe, Shun, Yoshida, Rie, Ushio, Yusuke, Sato, Masayo, Yajima, Aiji, Hanafusa, Norio, Tsuchiya, Ken, Nitta, Kosaku, Hoshino, Junichi, Mochizuki, Toshio
• Format: Article
• Language: English
• Subjects: Adult; Antidiuretic Hormone Receptor Antagonists - therapeutic use; Benzazepines - therapeutic use; Female; Follow-Up Studies; Glomerular Filtration Rate; Humans; Male; Middle Aged; Osmolar Concentration; Polycystic Kidney, Autosomal Dominant - drug therapy; Polycystic Kidney, Autosomal Dominant - physiopathology; Polycystic Kidney, Autosomal Dominant - urine; Prognosis; Prospective Studies; Tolvaptan - therapeutic use
• ISSN: 0931-0509; 1460-2385; 1460-2385
• DOI: 10.1093/ndt/gfad232

Tolvaptan, a vasopressin V2 receptor antagonist, is used for treating autosomal dominant polycystic kidney disease (ADPKD). We focused on changes in urinary osmolality (U-Osm) after tolvaptan initiation to determine whether they were associated with the therapeutic response to tolvaptan. This was a single-centre, prospective, observational cohort study. Seventy-two patients with ADPKD who received tolvaptan were recruited. We analysed the relationship between changes in U-Osm and annual estimated glomerular filtration rate (eGFR) in terms of renal prognostic value using univariable and multivariable linear regression analyses. The mean value of U-Osm immediately before tolvaptan initiation was 351.8 ± 142.2 mOsm/kg H2O, which decreased to 97.6 ± 23.8 mOsm/kg H2O in the evening. The decrease in U-Osm was maintained in the outpatient clinic 1 month later. However, the 1-month values of U-Osm showed higher variability (160.2 ± 83.8 mOsm/kg H2O) than did those in the first evening of tolvaptan administration. Multivariate analysis revealed that the baseline eGFR, baseline urinary protein and U-Osm change in the evening of the day of admission (initial U-Osm drop) were significantly correlated with the subsequent annual change in eGFR. U-Osm can be measured easily and rapidly, and U-Osm change within a short time after tolvaptan initiation may be a useful index for the renal prognosis in actual clinical practice.