Effects of Dietary Phosphorus on Phosphorus and Calcium Whole-Body Balance and Kinetics in Moderate CKD

NCT06712719 | Not Yet Recruiting

• 1 other identifier: TBD2
• Study Type: interventional
• Target: 14
• Locations: 0 countries
• Sites: N/A

Brief Summary

The aim of the study is to look at the effects of dietary phosphorus on phosphorous and calcium whole-body balance and kinetics in moderate chronic kidney disease (CKD). N = 14 enrolled subjects will be randomly assigned to a cross-over order of (A) Low P Diet, High P Diet. Each cross-over phase will be 19 days and consist of a 7-day outpatient, controlled diet period, followed by a 5- day inpatient, controlled diet, balance, and kinetic study period, followed by a second 7-day outpatient, controlled diet period.

Conditions

CKD

Outcome Measures

Primary Outcomes (2)

• Phosphorus Balance

  Determined by analysis of phosphorus content in complete 24-hour urine and stool collections, subtracted from the diet phosphorus content consumed

  5 days

• Calcium Balance

  Determined by analysis of calcium content in complete 24-hour urine and stool collections, subtracted from the diet calcium content consumed

  5 days

Secondary Outcomes (13)

• Fractional phosphorus absorption

  12 days

• Bone phosphorus balance

  12 days

• Bone calcium balance

  5 days and 12 days

• Urine phosphorus

  1 week

• Urine calcium

  1 week

Study Arms (2)

CKD patients group 1

EXPERIMENTAL

assigned to Low P Diet (LP) then High P Diet (HP),

Other: LP then HP

CKD patients group 2

EXPERIMENTAL

assigned to HP, then LP.

Other: HP then LP

Interventions

LP then HP OTHER

Cross-over order of LP then HP diet. Each cross-over phase will be 19 days and consist of a 7-day outpatient, controlled diet period, followed by a 5-day inpatient, controlled diet, balance, and kinetic study period, followed by a second 7-day outpatient, controlled diet period.

CKD patients group 1

HP then LP OTHER

Cross-over order of HP then LP diet. Each cross-over phase will be 19 days and consist of a 7-day outpatient, controlled diet period, followed by a 5-day inpatient, controlled diet, balance, and kinetic study period, followed by a second 7-day outpatient, controlled diet period.

CKD patients group 2

Eligibility Criteria

• Age: 30 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Men or women, ages 30-75 years old, any race or ethnicity
• Moderate CKD, defined by KDIGO as eGFR category 3b (30-44 mL/min) or 4 (16-29 mL/min) with albuminuria categories A1-A3
• Serum intact parathyroid hormone above assay normal limit
• Female subjects must be postmenopausal (\>12 months since last menstrual period), surgically sterile, or confirmed not pregnant by pregnancy test

You may not qualify if:

• Willing to discontinue 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 based on National Academy of Medicine (then Institute of Medicine) criteria.
• Plans to initiate dialysis within 6 months
• Hypercalcemia defined as corrected serum calcium \>9.8 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, bariatric surgery, or chronic diarrhea/malabsorption
• Serious, uncontrolled underlying systemic disease including diabetes, lupus, hypertension in the opinion of their physician
• Pregnant or breastfeeding
• Prescribed and taken a phosphate binder medication, calcitriol, vitamin D analogs, calcimimetics, PTH analogues, and other medications that may alter Ca and P metabolism within past 4 weeks
• Non-English speaking

Sponsors & Collaborators

• University of Minnesota: lead

Study Officials

• Kathleen Hill Gallant, PhD

  University of Minnesota

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Kathleen Hill Gallant, PhD

CONTACT

612-625-5285; hillkm@umn.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: November 26, 2024
• First Posted: December 2, 2024
• Study Start: May 1, 2026
• Primary Completion (Estimated): May 28, 2027
• Study Completion (Estimated): May 28, 2027
• Last Updated: March 17, 2026

Record last verified: 2026-03