Phosphorus Absorption in Healthy Adults and in Patients With Moderate Chronic Kidney Disease

NCT ID: NCT03108222

Last Updated: 2019-07-10

Basic Information

• Recruitment Status: UNKNOWN
• Total Enrollment: 20 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2018-04-25
• Study Completion Date: 2019-12-31

Brief Summary

Chronic kidney disease (CKD) affects approximately 26 million Americans with many more at risk for disease development. Elevated serum phosphorus (P) and related abnormalities in P homeostasis due to progressive loss of kidney function are primary driving forces behind cardiovascular dysfunction and mortality in CKD patients. Intestinal P absorption is an critical aspect in P homeostasis but has been understudied, particularly in the early stages of CKD progression. This study aims to determine P absorption in patients with moderate CKD compared to healthy adults.

Conditions

Chronic Kidney Disease Mineral and Bone Disorder

Study Design

• Observational Model Type: OTHER
• Study Time Perspective: PROSPECTIVE

Study Groups

Healthy Subjects

Healthy subjects, free of CKD

Phosphorus Absorption Test

Intervention Type: OTHER

Subjects will undergo a radiophosphorus (P-33) absorption test over two days, that will include an oral administration of P-33 on the 1st day of the test, and an IV administration of P-33 on the 2nd day of the test. P-33 activity from serial serum and urine collections will be determined by scintillation counting, and fractional phosphorus absorption calculated by kinetic modeling.

Moderate CKD Subjects

Subjects with moderate-stage CKD

Phosphorus Absorption Test

Intervention Type: OTHER

Subjects will undergo a radiophosphorus (P-33) absorption test over two days, that will include an oral administration of P-33 on the 1st day of the test, and an IV administration of P-33 on the 2nd day of the test. P-33 activity from serial serum and urine collections will be determined by scintillation counting, and fractional phosphorus absorption calculated by kinetic modeling.

Interventions

Phosphorus Absorption Test

Subjects will undergo a radiophosphorus (P-33) absorption test over two days, that will include an oral administration of P-33 on the 1st day of the test, and an IV administration of P-33 on the 2nd day of the test. P-33 activity from serial serum and urine collections will be determined by scintillation counting, and fractional phosphorus absorption calculated by kinetic modeling.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

Men and women ages 30-75 years old, any race

Moderate CKD, based on the last set of labs done in the past year, defined as:

Glomerular Filtration Rate (GFR) category G3a (eGFR 45-59 mL/min) with A2 or A3 albuminuria or proteinuria by positive dipstick or urine protein/creatinine ratio (UPCR); -or- G3b (eGFR 30-44 mL/min), with or without evidence of albuminuria (any A1-A3) or proteinuria. (Figure 1)

-or- Healthy control with no diagnosis or evidence of CKD

Female subjects must be post-menopausal, surgically sterile, or confirmed not pregnant by pregnancy test and not breastfeeding.

Exclusion Criteria

Exclusion:

Plans to initiate dialysis within 6 months

Labs based on the last set done in the past year:

Hypercalcemia defined as serum calcium > 10.5 mg/dL

Hyperkalemic > 5.5 mg/dL Prescribed a phosphate binder medication

Small bowel resection, bariatric surgery. Medically unstable or poorly controlled hypertension, diabetes, or gastrointestinal disorders in the opinion of the physicians on the study team

Calcitriol, ergocalciferol, cholecalciferol, vitamin D analogs, calcimimetics, PTH analogues, calcium supplements, multivitamins/mineral and other medications that may alter phosphorus metabolism - must be off for at least 6 weeks prior to study

• Minimum Eligible Age: 30 Years
• Maximum Eligible Age: 75 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Purdue University

OTHER

Sponsor Role: lead

Responsible Party

Kathleen Hill Gallant

Principal Investigator

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Purdue University Nutrition Science Department

West Lafayette, Indiana, United States

Countries

United States

References

Stremke ER, Wiese GN, Moe SM, Wastney ME, Moorthi RN, Hill Gallant KM. Intestinal Phosphorus Absorption in Moderate CKD and Healthy Adults Determined Using a Radioisotopic Tracer. J Am Soc Nephrol. 2021 Aug;32(8):2057-2069. doi: 10.1681/ASN.2020091340. Epub 2021 Jul 8.

Reference Type: DERIVED

PMID: 34244325 (View on PubMed)

Other Identifiers

1612460566

Identifier Type: -

Identifier Source: org_study_id