Patient Survey of current water Intake practices in autosomal dominant Polycystic kidney disease: the SIPs survey

Patient Perspectives on ADPKD

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disease. It has been associated with a significant physical and psychological burden, leading to a reduced quality of life. The purpose of this literature review is to summarize the patient perspective on ADPKD based on the current published literature. A systematic literature review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Publications reporting a patient or caregiver/relative perspective of ADPKD were included. Sources searched included Medline (PubMed), Embase (Ovid), Cochrane Library, and Web of Science from inception to April 2022. This was followed by a subsequent reference and citation search. A total of 1011 articles were identified by the search process, with 28 studies included in the review. An inductive thematic analysis identified six key themes: diagnosis, monitoring, and screening; symptoms; lifestyle and dietary interventions; psychological, physical, and social impact; future planning; and interaction with the health care system. The findings of this review highlight the burden and uncertainty associated with ADPKD from a patient's perspective. This impacts patients and their caregivers/relatives at each stage of the patient's journey from screening to initiation of renal replacement therapy and future planning.

Prescribed Water Intake in Autosomal Dominant Polycystic Kidney Disease

BACKGROUND: Arginine vasopressin promotes kidney cyst growth in autosomal dominant polycystic kidney disease (ADPKD). Increased water intake reduces arginine vasopressin and urine osmolality and may slow kidney cyst growth. METHODS: In this randomized controlled 3-year clinical trial, we randomly assigned adults with ADPKD who had a height-corrected total kidney volume in Mayo imaging subclass categories 1B to 1E and an estimated glomerular filtration rate of 30 ml/min/1.73 m2 or greater to (1) water intake prescribed to reduce 24-hour urine osmolality to 270 mOsmol/kg or less or (2) ad libitum water intake irrespective of 24-hour urine osmolality. The primary end point was the percentage annualized rate of change in height-corrected total kidney volume. RESULTS: A total of 184 patients participated in either the ad libitum water intake group (n=92) or the prescribed water intake group (n=92). Over 3 years, there was no difference in the annualized rate of change in height-corrected total kidney volume between the ad libitum (7.8% per year; 95% confidence interval [CI], 6.6 to 9.0) and prescribed (6.8% per year; 95% CI, 5.8 to 7.7) water intake groups (mean difference, −0.97% per year; 95% CI, −2.37 to 0.44; P=0.18). The difference in mean 24-hour urine osmolality between the ad libitum and prescribed water intake groups was −91 mOsmol/kg (95% CI, −127 to −54 mOsmol/kg), with 52.3% of patients achieving adherence to the target 24-hour urine osmolality and no reduction in serum copeptin over 3 years. The frequency of adverse events was similar between groups. CONCLUSIONS: For patients with ADPKD, prescribed water intake was not associated with excess adverse events and achieved the target 24-hour urine osmolality for half of the patients but did not reduce copeptin or slow the growth of total kidney volume over 3 years compared with ad libitum water intake. (Funded by the National Health and Medical Research Council of Australia [grant GNT1138533], Danone Research, PKD Australia, the University of Sydney, and the Westmead Medical Research Foundation; Australian New Zealand Clinical Trials Registry number, ACTRN12614001216606).

Targeted Therapies for Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is the most common life-threatening genetic disease in humans, affecting approximately 1 in 500 people. ADPKD is characterized by cyst growth in the kidney leading to progressive parenchymal damage and is the underlying pathology in approximately 10% of patients requiring hemodialysis or transplantation for end-stage kidney disease. The two proteins that are mutated in ADPKD, polycystin-1 and polycystin-2, form a complex located on the primary cilium and the plasma membrane to facilitate calcium ion release in the cell. There is currently no Food and Drug Administration (FDA)-approved therapy to cure or slow the progression of the disease. Rodent ADPKD models do not completely mimic the human disease, and therefore preclinical results have not always successfully translated to the clinic. Moreover, the toxicity of many of these potential therapies has led to patient withdrawals from clinical trials.

RESULTS

Here, we review compounds in clinical trial for treating ADPKD, and we examine the feasibility of using a kidney-targeted approach, with potential for broadening the therapeutic window, decreasing treatment-associated toxicity and increasing the efficacy of agents that have demonstrated activity in animal models. We make recommendations for integrating kidney- targeted therapies with current treatment regimes, to achieve a combined approach to treating ADPKD.

CONCLUSION

Many compounds are currently in clinical trial for ADPKD yet, to date, none are FDA-approved for treating this disease. Patients could benefit from efficacious pharmacotherapy, especially if it can be kidney-targeted, and intensive efforts continue to be focused on this goal.

Recent advances in the clinical management of autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic systemic disorder causing the development of renal and hepatic cysts and decline in renal function. It affects around 1 in 1,000 live births. Early hypertension and progressive renal failure due to massive enlargement of cysts and fibrosis are hallmarks of the disease. This article reviews recent advances in ADPKD and focuses mainly on diagnosis, management, and prediction of the course of the disease.

Randomised controlled trial of high versus ad libitum water intake in patients with autosomal dominant polycystic kidney disease: rationale and design of the DRINK feasibility trial

INTRODUCTION

Vasopressin stimulates cyst growth in autosomal dominant polycystic kidney disease (ADPKD) leading to enlarged kidneys, hypertension and renal failure. Vasopressin receptor blockade slows disease progression. Physiological suppression of vasopressin secretion through high water (HW) intake could achieve a similar effect, necessitating a definitive large-scale trial of HW intake in ADPKD. The objective of the DRINK trial is to answer the key design and feasibility questions required to deliver a successful definitive water intake trial.

METHODS AND ANALYSIS

We describe the design of a single-centre, open-label, prospective, randomised controlled trial. The "Determining feasibility of R andomisation to high vs. ad libitum water In take in Polycystic K idney Disease" (DRINK) trial aims to enrol 50 patients with ADPKD, over the age of 16 years with an estimated glomerular filtration rate (eGFR) ≥20 mL/min/1.73 m². Participants will be randomised 1:1 to HW intake based on an individualised water intake prescription, or to ad libitum (AW) water intake. The HW group will aim for a dilute urine (urine osmolality ≤270 mOsm/kg) as a surrogate marker of vasopressin suppression, and those in the AW group will target more concentrated urine. Participants will have an 8-week treatment period, and will be seen at weeks 0, 2, 4 and 8, undergoing assessments of fluid status, renal function and serum and urine osmolalities. They will receive dietary advice, and self-monitor urine specific gravity and fluid intake. The trial employs smartphone technology to permit home monitoring and remote direct data capture. The primary feasibility end points are recruitment rate and separation between arms in measured urinary osmolality. Key secondary assessments include acceptability, adherence, health-related quality of life, acute effects of HW intake on measured (⁵¹Cr-EDTA) and eGFR and ADPKD-related pain.

ETHICS AND DISSEMINATION

Ethical approval was awarded by the East of England Essex Research Ethics Committee (16/EE/0026). The results of DRINK will be submitted to peer-reviewed journals, and presented to patients via the PKD Charity.

TRIAL REGISTRATION NUMBER

NCT02933268 and ISCRTN16794957.

Nutritional therapy in autosomal dominant polycystic kidney disease

CKD-related nutritional therapy (NT) is a crucial cornerstone of CKD patients' treatment, but the role of NT has not been clearly investigated in autosomal dominant polycystic kidney disease (ADPKD). Several clinical studies have focused on new pharmacological approaches to delay cystic disease progression, but there are no data on dietary interventions in ADPKD patients. The aim of this paper is to analyze the evidence from the literature on the impact of five nutritional aspects (water, sodium, phosphorus, protein intake, and net acid load) in CKD-related ADPKD extrapolating-where information is unavailable-from what occurs in CKD non-ADPKD patients Sodium intake restriction could be useful in decreasing the growth rate of cysts. Although further evidence is needed, restriction of phosphorus and protein intake restriction represent cornerstones of the dietary support of renal non-ADPKD patients and common sense can guide their use. It could be also helpful to limit animal protein, increasing fruit and vegetables intake together with a full correction of metabolic acidosis. Finally, fluid intake may be recommended in the early stages of the disease, although it is not to be prescribed in the presence of moderate to severe reduction of renal function.

Inverting the patient involvement paradigm: defining patient led research

PLAIN ENGLISH SUMMARY

Patients usually understand their disease and lifestyle needs better than many medical professionals. They also have important ideas about what research would be most beneficial to their lives, especially on how to manage symptoms in a way that improves daily quality of life. In the UK, the National Institute for Health Research has recognised the value of patient insight, and now requires researchers with public funding to involve patients and the public throughout the research process. There are many opportunities for involvement, but these generally focus on improving study design to ensure the trial is acceptable to participants. Some programmes work towards setting research priorities as important to patients, public members, and medical experts, but due to the complexity and cost involved in running clinical trials, the majority of research originates with the pharmaceutical industry or academic institutions. There is a clear mismatch between research ideas that patients prioritise (quality of life), and those actually investigated (drug development).The Patient Led Research Hub (PLRH) is a new initiative hosted by the Cambridge Clinical Trials Unit. The PLRH supports research ideas as proposed by patient organisations, providing resources and expertise in research design and delivery. The PLRH aims to co-produce any technically feasible project, regardless of disease or symptom focus. The proposing patient group maintains ownership of the project with an active role in study management. This method of research has proven to produce credible research studies that are of direct relevance to patients.

ABSTRACT

Patient and Public Involvement has become an indispensable and expected component of healthcare research in the United Kingdom, largely driven by the National Institute of Health Research and other research funders. Opportunities for patients to become involved in research abound, and many organisations now have dedicated 'public involvement' teams. However, its value is often questioned amidst criticism of tokenism and the recognition that a mismatch persists between patient priorities and funded research. Although patients are frequently consulted, evidence that their involvement influences the research agenda remains limited. We propose a novel model that allows patients and the public not only to propose research questions, but to design, initiate and deliver their own research with all the necessary support from research professionals. We demonstrate the feasibility and utility of this approach in reporting the establishment, experiences and progress of the Patient Led Research Hub. Using this resource, patient organisations are now able to initiate and conduct rigorous clinical research unfettered by the constraints of academic or economic agendas.