According to researchers in Germany, polyuria induced by V2R-antagonists has caused concern regarding the tolerability of tolvaptan in the real-life setting. Questions regarding tolerability include how patients cope with increased urine volume, what is the sufficient adherence level to reach the desired effect, and how does the medication affect patients’ quality of life.
The researchers, led by Mussa Keaei, MSc, conducted the AD(H)PKD study, collecting data from patients with autosomal dominant polycystic kidney disease (ADPKD) presenting with the question whether they should take tolvaptan on a yearly basis. Results of the study were reported during a poster session at Kidney Week 2019 in a poster titled Using Tolvaptan for ADPKD: Feasibility and Patient-Reported Outcome in the Real-Life Setting.
One aspect of the study was a self-developed questionnaires to identify patient-reported outcomes, with particular focus on complications and adherence. Quality of life and pain measurements were ascertained using the 12 item Short Form (SF-12) Health Survey and a translated version of the HALT-PKD (Halt Progression of Polycystic Kidney Disease) study pain questionnaire.
The study began in late 2015; since the start, more than 560 patients have been enrolled. In the majority of patients on tolvaptan, urine volume increases to 5 to 75 liters. The largest increase occurs when initiating the first dose step; further uptitration leads to only a minor change. Adherence to long-term tolvaptan therapy is approximately 80%; most patients who discontinue therapy with tolvaptan reported events associated with polyuria.
The majority of patients in the study did not consider therapy with tolvaptan a major problem. However, approximately two-thirds report that a minor adaptation of everyday life was required. Approximately 65% reported that the increased urine volume presents a burden rarely; approximately 23% reported that the increases urine presents a burden often or always.
More than 90% said they would recommend tolvaptan therapy to other patients.
When asked about adherence, patients reported skipping a dose only rarely; leisure-time, professional, and medical reasons were cited as associated with skipping a dose. In the overall cohort, there was no difference in reported quality-of-life between patients with and without tolvaptan. There was also no difference longitudinally in patients prior to and following initiation of tolvaptan therapy.
In conclusion, the researchers said, “Our data indicate that taking tolvaptan—despite the increase in urine volume—is well feasible for most patients without major adaptations to everyday life. Around 20% consider the polyuria a significant burden and about the same percentage discontinued the therapy in the long term. Quality of life is not affected by polyuria and nearly all participants would tell others to try the therapy if recommended by their nephrologist. Taken together, our data will help to increase confidence of nephrologists in using tolvaptan for ADPKD and to guide patient counseling when starting the treatment.”
Source: Keaei M, Todorova P, Oehm S, et al. Using tolvaptan for ADPKD: Feasibility and patient-reported outcome in the real-life setting. Abstract of a poster presented at the American Society of Nephrology Kidney Week 2019 (Abstract TH-PO836), November 7, 2019, Washington, DC.