Phosphate Assessment in Chronic Kidney Disease Patients Study

NCT07368946 | Recruiting

• 2 other identifiers: STU-2024-124068418
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 1

Brief Summary

The proposed pilot feeding study aims to explore novel pathways in phosphate metabolism and identify new biomarkers, as well as to develop a compound index for assessing phosphate overload with high validity and reliability. Investigators will address the following specific aims: 1). To explore novel pathways of phosphate metabolism and assess the influence of CKD status on these metabolic pathways. 2). To identify novel biomarkers for phosphate overload that reflect changes in dietary phosphorus intake. 3). To develop a compound phosphate overload index that measures dietary phosphorus intake with high validity and reliability. This study will provide novel insights into phosphate metabolism and the assessment of phosphate overload in CKD patients. This investigation aims to provide preliminary data to further studies for the development of reliable biomarkers in CKD patients, which could contribute significantly to early interventions and improve health outcomes.

Conditions

Chronic Kidney Disease (Stage 3-4); Chronic Kidney Disease Mineral and Bone Disorder

Keywords

chronic kidney disease; study diet; feeding study; pilot; oral phosphate feeding

Outcome Measures

Primary Outcomes (5)

• Change in serum phosphate levels

  Circulating serum phosphate levels (mg/dL) will be measured using standard clinical laboratory assays

  Baseline, week 1, week 2, and week 3

• Change in parathyroid hormone (PTH) levels

  Circulating PTH levels (pg/mL) will be measured using standard clinical laboratory assays

  Baseline, week 1, week 2, and week 3

• Change in C-terminal Fibroblast Growth Factor 23 (FGF23) levels

  Circulating C-terminal FGF23 levels (RU/mL) will be measured using standard clinical laboratory assays

  Baseline, week 1, week 2, and week 3

• Change in Fibroblast Growth Factor 23 (FGF23) levels

  Circulating FGF23 levels (pg/mL) will be measured using standard clinical laboratory assays

  Baseline, week 1, week 2, and week 3

• Phosphate burden indices

  Phosphate burden indices, developed using machine learning methods to systematically incorporate both known biomarkers and novel biomarkers. No units have been identified, we anticipate creating a score.

  Baseline, week 1, week 2, week 3

Secondary Outcomes (6)

• Change in serum calcium levels

  Baseline, week 1, week 2, and week 3

• Change in Alkaline Phosphatase (ALP) levels

  Baseline, week 1, week 2, and week 3

• Change in 1,25-dihydroxyvitamin D levels

  Baseline, week 1, week 2, and week 3

• Change in Bone-Specific Alkaline Phosphatase (BALP) levels

  Baseline, week 1, week 2, and week 3

• Change in urinary calcium levels

  Baseline, week 1, week 2, and week 3

Other Outcomes (2)

• Exploratory: Phosphate-related biomarkers identified using proteomics platforms

  Baseline, week 1, week 2, week 3

• Exploratory: Phosphate-related biomarkers identified using metabolomics platforms

  Baseline, week 1, week 2, week 3

Study Arms (2)

Chronic Kidney Disease Patients

ACTIVE COMPARATOR

Participants with eGFR \>15 ml/min/1.73m2 - \< 60 ml/min/1.73m2 for the CKD group

Dietary Supplement: Dietary Phosphorus Intake

Control Group

ACTIVE COMPARATOR

Healthy participants without CKD eGFR ≥ 60 ml/min/1.73m2

Dietary Supplement: Dietary Phosphorus Intake

Interventions

Dietary Phosphorus Intake DIETARY_SUPPLEMENT

Dietary phosphorus intake of about 777 mg/day for 7 days, followed by an increase to about 1,277mg/day for another 7 days, and a further increase to about 1,777 mg/day for the subsequent 7 days. The meal plan will maintain consistent intake of calories, sodium, potassium, and calcium throughout the 21-day intervention. 1200 mg/day and 1700 mg/day phosphorus diets will be achieved by providing participants with sodium phosphate capsules and 777 mg/day meals.

Chronic Kidney Disease Patients; Control Group

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Men or women aged 18 years or older, of any race/ethnicity
• Women must either be post-menopausal or have no monthly menstrual cycle
• Estimated total daily energy expenditure (TDEE) of 1700 - 2700 calories
• eGFR \>15 ml/min/1.73m2 - \< 60 ml/min/1.73m2 for the CKD group (CKD Stage 3 or Stage 4)
• eGFR ≥ 60 ml/min/1.73m2 and negative urine protein on dipstick test for the non-CKD group
• English speaking

You may not qualify if:

• Pregnant, currently breastfeeding, or \<3 months postpartum
• Current dialysis or kidney transplant patient
• Current use of insulin or chemotherapy drugs
• Smokes cigarettes or uses e-cigarettes (vapes)
• Uses nicotine products or other recreational drugs
• Medical history of stroke or myocardial infarction (MI)
• Medical history of conditions that can affect phosphate metabolism (i.e., uncontrolled thyroid disorder, parathyroid disorder, or gastrointestinal malabsorption disorders \[Crohn's, ulcerative colitis, and celiac disease\], cirrhosis)
• Current use of certain medications that directly alter phosphate levels (i.e., phosphate binders; phosphate supplements, irregular use of iron)
• Regular use of laxatives
• Hypo- or hyperphosphatemia (serum phosphate \< 2.5 or \> 4.6 mg/dl)
• Hypo- or hypercalcemia (serum calcium \< 8.4 or \> 10.7 mg/dl)
• Severe anemia (hemoglobin \< 8 g/dl for women and \< 9 g/dl for men)
• Severe hyperglycemia (serum blood glucose \> 300 mg/dl)
• Body weight less than \<110 lbs (due to risk for phlebotomy-induced anemia)
• Received a blood transfusion in the last four months

Sponsors & Collaborators

• University of Texas Southwestern Medical Center: lead

Study Sites (1)

University of Texas Southwestern Medical Center

Dallas, Texas, 75390, United States

RECRUITING

MeSH Terms

Conditions

Renal Insufficiency, Chronic; Chronic Kidney Disease-Mineral and Bone Disorder

Condition Hierarchy (Ancestors)

Renal Insufficiency; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Male Urogenital Diseases; Chronic Disease; Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Rickets; Bone Diseases, Metabolic; Bone Diseases; Musculoskeletal Diseases; Metabolic Diseases; Nutritional and Metabolic Diseases; Calcium Metabolism Disorders; Vitamin D Deficiency; Avitaminosis; Deficiency Diseases; Malnutrition; Nutrition Disorders; Hyperparathyroidism, Secondary; Hyperparathyroidism; Parathyroid Diseases; Endocrine System Diseases

Study Officials

• Jing Chen, MD

  University of Texas Southwestern Medical Center

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Alexandra Hartman

CONTACT

214-645-8294; pack.utsw@utsouthwestern.edu

Paola Lanza, MD

CONTACT

469-852-9550; paola.lanza@utsouthwestern.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: DIAGNOSTIC
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Study Record Dates

• First Submitted: November 17, 2025
• First Posted: January 27, 2026
• Study Start: May 9, 2025
• Primary Completion (Estimated): December 31, 2026
• Study Completion (Estimated): December 31, 2026
• Last Updated: January 28, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL

Locations

US (1)