Completed

Effects of Dietary Phosphorus Restriction on Calcium and Phosphorus Balance in Chronic Kidney Disease Patients

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Study Aim

This study aims to investigate how restricting dietary phosphorus intake affects calcium and phosphorus balance in patients with chronic kidney disease, through analyzing calcium and phosphorus content in urine and stool collections and modeling isotope kinetics in serum and urine.

What is being tested

High Phosphorus Diet

+ Low Phosphorus Diet

Other
Who is being recruted

Urogenital Diseases+26

+ Avitaminosis

+ Bone Diseases

From 30 to 75 Years
See all eligibility criteria
How is the trial designed

Basic Science Study

Interventional
Study Start: August 2020
See protocol details

Summary

Principal SponsorUniversity of Minnesota
Last updated: January 28, 2026
Sourced from a government-validated database.Claim as a partner

Study start date: August 31, 2020

Actual date on which the first participant was enrolled.

This study focuses on understanding how calcium and phosphorus are processed in the bodies of individuals with moderate Chronic Kidney Disease (CKD). The main aim is to gather preliminary data on how a common dietary restriction of phosphorus impacts calcium and phosphorus balance and movement in these patients. This research is important as it could support a larger future clinical study, potentially improving care for those with CKD. Participants in this study will be assigned to one of two controlled diets: either a low calcium/high phosphorus diet or a low calcium/low phosphorus diet. After a week of following the diet at home, participants will spend a week in the hospital for full balance testing, including a 48-hour calcium and phosphorus absorption test. Following a break, participants will then switch to the other diet. The study measures the balance and absorption of calcium and phosphorus by analyzing their content in complete 24-hour urine and stool collections, and by using kinetic modeling of isotopes after oral and IV administrations. The results could provide valuable insights into dietary management for individuals with CKD.

Official TitleCalcium and Phosphorus Whole-Body Balance and Kinetics in Patients With Moderate Chronic Kidney Disease
NCT04019379
Principal SponsorUniversity of Minnesota
Last updated: January 28, 2026
Sourced from a government-validated database.Claim as a partner

Protocol

This section provides details of the study plan, including how the study is designed and what the study is measuring.
Design Details

3 patients to be enrolled

Total number of participants that the clinical trial aims to recruit.

Basic Science Study

Basic science studies help researchers understand how the body works or how a disease develops. They don't test treatments, but they build the foundation for future therapies.



Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.
Conditions
Criteria

Any sex

Biological sex of participants that are eligible to enroll.

From 30 to 75 Years

Range of ages for which participants are eligible to join.

Healthy volunteers not allowed

If individuals who are healthy and do not have the condition being studied can participate.

Conditions

Pathology

Urogenital DiseasesAvitaminosisBone DiseasesBone Diseases, MetabolicCalcium Metabolism DisordersChronic DiseaseDeficiency DiseasesEndocrine System DiseasesFemale Urogenital Diseases and Pregnancy ComplicationsHyperparathyroidismHyperparathyroidism, SecondaryKidney DiseasesMetabolic DiseasesMusculoskeletal DiseasesNutrition DisordersNutritional and Metabolic DiseasesParathyroid DiseasesPathologic ProcessesChronic Kidney Disease-Mineral and Bone DisorderRicketsPathological Conditions, Signs and SymptomsUrologic DiseasesVitamin D DeficiencyDisease AttributesMalnutritionRenal Insufficiency, ChronicRenal InsufficiencyFemale Urogenital DiseasesMale Urogenital Diseases

Criteria

Inclusion Criteria: * Men or women, ages 30-75 years old, any race or ethnicity * Moderate chronic kidney disease * Female subjects must be postmenopausal (\>12 months since last menstrual period), surgically sterile, or confirmed not pregnant by pregnancy test * Must be on stable doses of medications (except those noted in exclusion criteria) for at least 4 weeks prior to the study * Willing to discontinue nutritional supplements (e.g. vitamin D, calcium, multivitamin/minerals, or others) upon enrollment until completion of the study * Adequate vitamin D status defined as serum 25D \> 20 ng/mL Exclusion Criteria: * Plans to initiate dialysis within 6 months * Hypercalcemia defined as serum calcium \>10.5 mg/dL within past 3 months * Hyperkalemia defined as serum potassium \>5.5 mg/dL within past 3 months * Hyperphosphatemia defined as serum phosphate \>5.5 mg/dL within past 3 months * Intestinal disease that alters absorption or normal intestinal function including celiac disease, small bowel resection, or bariatric surgery * Serious, uncontrolled underlying systemic disease including diabetes, lupus, hypertension * Pregnant or breastfeeding * Prescribed a phosphate binder medication, calcitriol, vitamin D analogs, calcimimetics, parathyroid hormone analogues, and other medications that may alter Ca and P metabolism within past 30 days

Study Plan

Find out more about all the medication administered in this study, their detailed description and what they involve.
Treatment Groups
Study Objectives

2 intervention groups are designated in this study

This study does not include a placebo group 

Treatment Groups

Group I

Experimental
High Phos crossover to Low Phos

Group II

Experimental
Low Phos crossover to High Phos

Study Objectives

Primary Objectives

Secondary Objectives

Study Centers

These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.

This study has 1 location

Suspended

Indiana CTSI CRC

Indianapolis, United StatesOpen Indiana CTSI CRC in Google Maps
CompletedOne Study Center