Actively Recruiting
A Pilot Feeding Study to Assess Phosphate Overload in Patients With Chronic Kidney Disease
Led by University of Texas Southwestern Medical Center · Updated on 2026-01-28
60
Participants Needed
1
Research Sites
N/A
Total Duration
On this page
AI-Summary
What this Trial Is About
This research aims to explore new pathways in phosphate metabolism and identify novel biomarkers for phosphate overload, especially in people with chronic kidney disease (CKD). The study seeks to understand how CKD affects these metabolic pathways and to develop a reliable index to measure phosphate overload based on dietary intake. The goal is to provide preliminary data that could help improve early interventions and health outcomes for CKD patients. The study will include 60 participants, 30 with CKD and 30 without, who will follow a 21-day diet with gradually increasing phosphorus intake. For the first 7 days, participants consume about 777 mg/day of phosphorus, then increase to about 1,277 mg/day for the next 7 days, and finally to about 1,777 mg/day for the last 7 days. Sodium phosphate capsules and controlled meals will be used to maintain consistent intake of calories, sodium, potassium, and calcium throughout the study. Participants will provide overnight fasting blood samples and 24-hour and random urine samples at the start and end of each diet phase to measure changes in phosphate, parathyroid hormone, fibroblast growth factors, calcium, vitamin D, and other related biomarkers. The study will monitor these measures weekly over three weeks to assess phosphate overload and related metabolic changes. The total study duration per participant is 21 days, focusing on detailed metabolic assessments.
CONDITIONS
Brief Title
Phosphate Assessment in Chronic Kidney Disease Patients Study
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Men or women aged 18 years or older, of any race or ethnicity
- Women must be post-menopausal or not have monthly menstrual cycles
- Estimated total daily energy expenditure (TDEE) between 1700 and 2700 calories
- For CKD group: eGFR between 15 and less than 60 ml/min/1.73m2 (Stage 3 or 4 CKD)
- For non-CKD group: eGFR at least 60 ml/min/1.73m2 with negative urine protein dipstick
- Ability to speak and read English
You will not qualify if you...
- Pregnant, currently breastfeeding, or less than 3 months postpartum
- Receiving dialysis or have had a kidney transplant
- Currently using insulin or chemotherapy drugs
- Smoking cigarettes or using e-cigarettes (vapes)
- Using nicotine products or other recreational drugs
- History of stroke or heart attack
- Conditions affecting phosphate metabolism such as uncontrolled thyroid or parathyroid disorders, gastrointestinal malabsorption, or cirrhosis
- Using medications that affect phosphate levels, including phosphate binders or supplements
- Regular use of laxatives
- Abnormal phosphate or calcium levels in the blood
- Severe anemia or very high blood sugar
- Body weight less than 110 pounds
- Blood transfusion within the last four months
- Extreme high or low blood pressure
- Unwilling or unable to eat study meals
- Lack of access to a functional refrigerator, freezer, microwave, or conventional oven
- Following a low potassium or low phosphate diet
- Specific dietary restrictions such as vegetarian, vegan, or ketogenic diets
- Food allergies including milk, egg, soy, nuts, shellfish, wheat, or gluten
- Allergy to sodium phosphate
- Unable or unwilling to provide urine samples or complete food diaries
- Unable or unwilling to give informed consent
- Unable to read or speak English
- Participating in another conflicting clinical trial
- Unable to complete study measurements
- Unsafe to participate as judged by the investigator
AI-Screening
AI-Powered Screening
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Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 visit (in-person)
Duration - 21 days
Participants follow a 21-day diet intervention with increasing phosphorus intake: about 777 mg/day for 7 days, then about 1,277 mg/day for 7 days, and finally about 1,777 mg/day for 7 days. The meal plan maintains consistent intake of calories, sodium, potassium, and calcium throughout the intervention. Sodium phosphate capsules and meals are provided to achieve the target phosphorus levels.
Blood and urine samples collected at baseline and end of each 7-day phase (4 visits total)
Trial Site Locations
Total: 1 location
1
University of Texas Southwestern Medical Center
Dallas, Texas, United States, 75390
Actively Recruiting
Research Team
A
Alexandra Hartman
P
Paola Lanza, MD
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NON_RANDOMIZED
Model
PARALLEL
Primary Purpose
DIAGNOSTIC
Number of Arms
2
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