Di-PKD: A Pilot Trial of Dietary Intervention in Patients With Autosomal Dominant Polycystic Kidney Disease (ADPKD)

Di-PKD: A Pilot Trial of a 12-Month Targeted Dietary Intervention on Cyst Progression in Patients With Autosomal Dominant Polycystic Kidney Disease

The goal of this interventional study is to evaluate the impact of a specific diet (low salt, limited caffeine, high potassium, low phosphate, limited protein, limited carbohydrate intake, adequate water intake) on changes in serum and urinary biomarkers, total kidney volume (TKV), and cyst progression in subjects with autosomal dominant polycystic kidney disease (ADPKD).

Researchers will compare the results of subjects in the study diet (interventional) arm to the results of subjects in the regular diet (control) arm.

Study Overview

• Status: Not yet recruiting
• Conditions: Autosomal Dominant Polycystic Kidney Disease (ADPKD)
• Intervention / Treatment: Other: Interventional Diet

Detailed Description

15 subjects will be enrolled in each dietary arm for a total of 30 subjects. All subjects will follow the study diet for one week, after which serum and urinary biomarkers will be measured. A baseline evaluation, including genetic testing, MRI, Mayo Clinic Imaging Classification and 10-question survey will also be conducted. After Week 1 of the study, subjects will be assigned to the intervention or control arm. Subjects will have six follow-up visits at months 1, 2, 3, 6, 9 and 12 to assess adherence to diet. Serum and urinary biomarkers will be repeated at each visit. MRI will be repeated at Month 12.

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Niloufar Ebrahimi Ebrahimi, MD; Phone Number: 55885 909-558-4000; Email: Nebrahimi@llu.edu
• Study Contact Backup: Name: Sayna Norouzi, MD; Phone Number: 909-558-4000; Email: Snorouzi@llu.edu

Study Locations

• United States
  • California
    • Loma Linda, California, United States, 92354
      • Loma Linda University Health
      • Contact: Amir Abdipour, MD; Phone Number: 909-202-0252

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Confirmed diagnosis of ADPKD
• Genetic testing confirmation of PKD1 or PKD2
• eGFR >30mL/1.73m2
• Willingness to adhere to a preconditioning diet for 1 week and ability to complete the study
• Mayo Clinic Imaging Classification (MCIC): 1C, 1D, 1E

Exclusion Criteria:

• History of dietary non-adherence
• Subjects on Tolvaptan
• Comorbidities that could interfere with participation (Diabetes, Heart Failure (EF<30%) Advanced Chronic Kidney Disease (CKD) Stage 4 and higher)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Interventional Diet; Subjects will follow a specified diet (low salt, limited caffeine, high potassium, low phosphate, and limited protein and carbohydrate intake along with adequate water intake) after 1 week of preconditioning for 12 months.	Other: Interventional Diet; Low salt, limited caffeine, high potassium, low phosphate, and limited protein and carbohydrate intake along with adequate water intake diet
No Intervention: Regular Diet; Subjects will follow the diet they normally adhere to after 1 week of preconditioning.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Progression of kidney cysts by change in total kidney volume (TKV) from baseline to 12 months	A composite measurement of MRI to determine total kidney volume (TKV) by kidney length, width, and depth will be done at baseline and again at 12 months. MRI results will be compared between the two-time points to assess the cyst progression, if any. An increase of about 5% per year from baseline will be significant.	Change between baseline and 12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Progression of kidney cysts as evidenced by urinary biomarkers from baseline to 12 months	A urine sample will be collected at the end of the preconditioning week to establish a baseline for the urinary biomarkers cAMP and MCP-1. This is a composite measurement. Values for cAMP and MCP-1 at 12 months will be compared to the baseline values. If the values at 12 months remain the same or less than the composite baseline values, this will indicate a low likelihood that the kidney cysts have progressed. A significant change of 20% or greater overall in the combined biomarkers will indicate a kidney cyst progression.	Change between baseline and 12 months
Progression of kidney cysts as evidenced by serum biomarkers from baseline to 12 months	A blood draw will be performed at the end of the preconditioning week to establish a baseline for the serum biomarkers uric acid, ADH, FGF-23, bicarbonate, and cystatin C. This is a composite measurement. Values for uric acid, ADH, FGF-23, bicarbonate, and cystatin C at 12 months will be compared to the baseline values. If the values at 12 months remain the same or less than the composite baseline values, this will indicate a low likelihood that the kidney cysts have progressed. A significant change of 20% or greater overall in the combined biomarkers will indicate a kidney cyst progression.	Change between baseline and 12 months

Collaborators and Investigators

• Sponsor: Loma Linda University
• Investigators: Principal Investigator: Amir Abdipour, MD, Loma Linda University Health

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): April 1, 2027

Study Registration Dates

• First Submitted: January 10, 2025
• First Submitted That Met QC Criteria: January 15, 2025
• First Posted (Actual): January 22, 2025

Study Record Updates

• Last Update Posted (Actual): January 30, 2026
• Last Update Submitted That Met QC Criteria: January 28, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Diet; ADPKD
• Additional Relevant MeSH Terms: Ciliopathies; Urogenital Diseases; Male Urogenital Diseases; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Genetic Diseases, Inborn; Congenital Abnormalities; Abnormalities, Multiple; Kidney Diseases, Cystic; Polycystic Kidney Diseases; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Polycystic Kidney, Autosomal Dominant
• Other Study ID Numbers: 5240615

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No