An interventional study of Dietary in Polyuria and Autosomal Dominant Polycystic Kidney, sponsored by McMaster University. Completed at 1 site in Canada. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2024-03-15.
Sponsored by McMaster University · Not applicable, Interventional, and Treatment
Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited renal disorder. Tolvaptan has been approved in Canada as a treatment for ADPKD. Tolvaptan is an arginine vasopressin receptor antagonist which has been shown to decrease the progression of ADPKD. The main side effect of this treatment is increased urine output which leads to cessation of therapy in about 20% of patients. Low solute (low sodium, low protein) diet may alleviate this side effect. This is a single arm before / after study of dietary intervention on urine output and quality of life in ADPKD patients on a stable dose of tolvaptan.
Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited renal disorder affecting 12.5 million persons worldwide, and impacting approximately 35,000-66,000 Canadians. An estimated 45% to 70% of patients with ADPKD progress to end-stage renal disease by age 65 years.
Tolvaptan has been approved in Canada as a treatment for ADPKD. Tolvaptan was discovered in Japan by Otsuka Pharmaceutical and was first approved there for ADPKD in 2014. The Health Canada approval of Tolvaptan is based on the results of the pivotal Phase 3 randomized, double-blind and placebo-controlled TEMPO 3:4 Trial, the largest study conducted to date in adults with ADPKD.
The treatment of ADPKD had previously been symptomatic with the aim of reducing morbidity and mortality associated with disease manifestations. This changed with the publication of the TEMPO 3:4 trial, which proved the efficacy of the arginine vasopressin (AVP) V2 receptor antagonist tolvaptan in decreasing the progression of CKD. In this trial, 1445 patients with ADPKD eGFR > 60 were randomized to receive either placebo or tolvaptan in a split-dose regimen of 45 mg in the morning and 15 mg in the afternoon, up titrated to 90/30 mg as tolerated. The REPRISE study investigated the value of tolvaptan in 1300 patients with lower levels of eGFR (25-65 mL/min/1.73 m2).
AVP plays a major role in the pathogenesis of cysts in ADPKD via cAMP stimulation. The AVP antagonist blocks V2 receptors in collecting ducts and therefore blocks the concentrating ability of the tubule. This leads to increased urine volume. Recently, it has been demonstrated that this increased urine volume is related to solute excretion. Therefore, it seems possible that dietary modification to decrease solute intake (salt, protein) would decrease the urine volume in patients taking tolvaptan.
The most common side effect of AVP antagonist is increased renal water excretion which presents as polyuria, nocturia, increased thirst, and dry mouth. The daily urine volumes 5 days after starting different split doses of tolvaptan (15/15, 30/0, 30/15, 30/30 mg) in a preliminary phase 2 study were 4 to 6 L. In the treatment of hyponatremia and heart failure (another indication for tolvaptan therapy), a meta-analysis found an average increase in water clearance of only 68 mL/h after tolvaptan treatment. This more modest increase in urine output may be related to the low sodium diet most of these patients should be adhering to.
14 studies on the registry are indexed under Polyuria; 2 are open to participants now.
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Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Single arm study. All participants will receive dietary intervention.
Other: Dietary
Low sodium, low protein dietary recommendation
Change in 24-hour urine volume
24-hour urine volume in ml.
Time frame: Change from baseline to 3 months
Change in ADPKD-IS
Autosomal dominant polycystic kidney disease impact score - quality of life. Eighteen items, score from 18 to 90 with higher values reflecting lower quality of life
Time frame: Change from baseline to 3 months
Change in Nagasaki Diabetes Insipidus Questionnaire
Validated measure of polyuria on quality of life. Subset of questions 1-10 will be used (Questions 11-12 relate to therapy with DDAVP). Score from 10 to 40 with higher scores reflecting worse quality of life.
Time frame: Change from baseline to 3 months
Change in urine total solute
Urine total solute measured by (urine sodium + urine urea) \* urine volume
Time frame: Change from baseline to 3 months
Plan to share: No
No publications or documents are linked to this record.
Ran from Jun 2019 to primary completion in Sep 2021, 27 months.
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This study is completed, as verified in Mar 2024. You cannot join it, but the record below documents what was studied.
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