Introduction Maintaining fluid intake sufficient to reduce arginine vasopressin (AVP) secretion has been hypothesised to slow kidney cyst growth in autosomal dominant polycystic kidney disease (ADPKD). However, evidence to support this as a clinical practice recommendation is of poor quality. The aim of the present study is to determine the long-term efficacy and safety of prescribed water intake to prevent the progression of height-adjusted total kidney volume (ht-TKV) in patients with chronic kidney disease (stages 1–3) due to ADPKD.
Methods and analysis A multicentre, prospective, parallel-group, open-label, randomised controlled trial will be conducted. Patients with ADPKD (n=180; age ≤65 years, estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73 m2) will be randomised (1:1) to either the control (standard treatment+usual fluid intake) or intervention (standard treatment+prescribed fluid intake) group. Participants in the intervention arm will be prescribed an individualised daily fluid intake to reduce urine osmolality to ≤270 mOsmol/kg, and supported with structured clinic and telephonic dietetic review, self-monitoring of urine-specific gravity, short message service text reminders and internet-based tools. All participants will have 6-monthly follow-up visits, and ht-TKV will be measured by MRI at 0, 18 and 36 months. The primary end point is the annual rate of change in ht-TKV as determined by serial renal MRI in control vs intervention groups, from baseline to 3 years. The secondary end points are differences between the two groups in systemic AVP activity, renal disease (eGFR, blood pressure, renal pain), patient adherence, acceptability and safety.
Ethics and dissemination The trial was approved by the Human Research Ethics Committee, Western Sydney Local Health District. The results will inform clinicians, patients and policy-makers regarding the long-term safety, efficacy and feasibility of prescribed fluid intake as an approach to reduce kidney cyst growth in patients with ADPKD.
Trial registration number ANZCTR12614001216606.
- chronic renal failure
- adult nephrology
- magnetic resonance imaging
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Contributors All authors contributed and developed the study protocol. The rationale and hypothesis for the trial arose from reviews and pilot studies in humans authored by JGG and supported by the results of the TEMPO 251 clinical trial. GKR developed the initial version of the study protocol with JJG, DCHH, VWL and KS. ATYW, CM, MAF and AR contributed to the implementation of the intervention. KB provided initial biostatistical advice and suggested using SMS texting as a potential measure of compliance in the control group. JH and PM provided biostatistical advice and developed the biostatistical plan. JC developed eCRF and data management protocols. KH and MH developed the protocol for health economic analysis. SF, TP, VT, BJE, TLK and MEE developed protocols on analysis of TKV by MRI. DWJ and CHH provided input on trial oversight and overall management. SC, SVB, NB, IH, SHJ, JM, CM, AP, SDR, EV provided additional input into the study protocol.
Funding The development and commencement of the trial was funded by University of Sydney Bridging Grants (2014, 2016), Westmead Medical Research Foundation, the Western Sydney Local Health District and an investigator-initiated research grant from Danone Nutricia Research (France).
Competing interests The study protocol was developed independently by the authors listed of this manuscript. GR is the sole principal investigator listed on the grant received from Danone Nutricia Research to conduct this trial. The grant was awarded in December 2015 and is being administered by the study sponsor (Western Sydney Local Health District). GR has received travel support from Danone Nutricia Research to attend an international meeting on hydration (2016 and 2017). No other authors have competing interests to declare.
Patient consent Not required.
Ethics approval The trial was approved by the Human Research Ethics Committee of the Western Sydney Local Health District in 2014.
Provenance and peer review Not commissioned; externally peer reviewed.
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