Clinical trial NCT03108222: Phosphorus Absorption in Healthy Adults and in Patients With Moderate Chronic Kidney Disease
Official title: Phosphorus Absorption in Healthy Adults and in Patients With Moderate Chronic Kidney Disease
Study type: OBSERVATIONAL
Overall status: UNKNOWN
Conditions: Chronic Kidney Disease Mineral and Bone Disorder
Keywords: chronic kidney disease
CKD
renal failure
phosphorus
phosphate
intestinal absorption
Lead sponsor: Purdue University
Sponsor class: OTHER
First posted: 2017-04-11
Enrollment: 20
Sex: ALL
Minimum age (years): 30
Maximum age (years): 75
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: OTHER
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Healthy subjects and subjects with moderate CKD will be recruited from the community.

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.


Eligibility criteria: Inclusion:

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.

Subjects must be on stable doses of medications (except those noted in exclusion criteria) for at least 6 weeks prior to the study

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

Primary outcomes:
measure: Fractional Phosphorus Absorption
timeFrame: Measured from serial blood draws over a 4-hour time frame
Secondary outcomes:
measure: Serum FGF23
timeFrame: Measured from baseline measures and serial blood draws over a 4-hour time frame
measure: Serum 1,25(OH)2D
timeFrame: Measured from baseline measures and serial blood draws over a 4-hour time frame
measure: Serum parathyroid hormone (PTH)
timeFrame: Measured from baseline measures and serial blood draws over a 4-hour time frame
measure: Serum phosphate
timeFrame: Measured from baseline measures and serial blood draws over a 4-hour time frame
measure: 24h Urine phosphate
timeFrame: measured from two, 24-hour urine collections
Other outcomes:
Locations:
city: West Lafayette
country: United States
facility: Purdue University Nutrition Science Department
state: Indiana
Study officials:
References:
citation: 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.