Study of Dietary Phosphate and Mineral Homeostasis in Early Chronic Kidney Disease - Full Text View

Sponsored by:	University of British Columbia
Information provided by:	University of British Columbia
ClinicalTrials.gov Identifier:	NCT00755690

Purpose

This study is designed to describe the physiological response to increased and decreased dietary phosphate intake on various parameters of mineral metabolism in the blood and urine of individuals with Chronic Kidney Disease stage 3 and 4 with normal serum phosphate levels. This detailed study will give us a far greater understanding of the role of diet in abnormal mineral homeostasis early in the progression of this chronic disease. The findings of this study will help both physicians and dietitians better determine the optimal time to introduce dietary therapy in CKD.

Condition	Intervention
Kidney Diseases	Behavioral: High/ Low Phosphate diet

MedlinePlus related topics: Minerals

Drug Information available for: Aluminum hydroxide Algeldrate Aluminum

U.S. FDA Resources

Study Type:	Interventional
Study Design:	Treatment, Randomized, Open Label, Active Control, Crossover Assignment, Efficacy Study
Official Title:	Study of Dietary Phosphate and Mineral Homeostasis in Early Chronic Kidney Disease

Further study details as provided by University of British Columbia:

Primary Outcome Measures:

FGF-23 [ Time Frame: 5 days ] [ Designated as safety issue: No ]

Secondary Outcome Measures:

Serum calcium, phosphate, PTH, 25 and 1,25 vitamin D and fractional phosphate excretion. [ Time Frame: 5 days ] [ Designated as safety issue: No ]

Estimated Enrollment:	30
Study Start Date:	September 2008
Estimated Study Completion Date:	December 2009
Estimated Primary Completion Date:	September 2009 (Final data collection date for primary outcome measure)

Arms	Assigned Interventions
1: Active Comparator High/ Low Phosphate diet I. A five-day low phosphate diet / A five-day low phosphate diet with the addition of a phosphate binder / A five-day high phosphate diet. II. A five-day low phosphate diet / A five-day high phosphate diet / A five-day low phosphate diet with the addition of a phosphate binder III. A five-day high phosphate diet / A five-day low phosphate diet with the addition of a phosphate binder / A five-day low phosphate diet. IV. A five-day high phosphate diet / A five-day low phosphate diet / A five-day low phosphate diet with the addition of a phosphate binder. V. A five-day low phosphate diet with the addition of a phosphate binder / A five-day low phosphate diet / A five-day high phosphate diet. VI. A five-day low phosphate diet with the addition of a phosphate binder / A five-day high phosphate diet / A five-day low phosphate diet.	Behavioral: High/ Low Phosphate diet Low phosphate diet (750mg/day).
2: Active Comparator High/ Low Phosphate diet	Behavioral: High/ Low Phosphate diet Low phosphate diet (750mg/day) with the addition of the phosphate binder aluminum hydroxide (500mg three times per day).
3: Active Comparator High/ Low Phosphate diet	Behavioral: High/ Low Phosphate diet III. High phosphate diet (2000mg /day).

Detailed Description:

The potential benefits of implementation of phosphate management earlier in CKD (Stages 3/4) are threefold: 1) prevention of vascular damage early in the progression of CKD thus reducing risk of cardiovascular death 2) Improved management of renal bone disease and resultant co-morbidities and 3) slowing the progression of renal failure lengthening the time required till dialysis is required. Although dietary counseling is currently a normal part of CKD care, the utility and effectiveness of lowering phosphate has not previously been quantified. In part this is due to the difficulty of measurement of serum phosphate as it is so tightly controlled before GFR falls below 30mls/min. No studies have investigated whether is it possible to modulate circulating FGF-23 and phosphate excretion in early stages of renal failure using diet in individuals with normal serum phosphate levels.

Study Objectives ;

To measure FGF-23 levels before and after a high phosphate diet, low phosphate diet and a low phosphate diet with phosphate binders.
To measure levels of calcium, phosphate, PTH, 25 and 1,25 vitamin D and fractional phosphate excretion before and after a high phosphate diet, low phosphate diet and a low phosphate diet with phosphate binders.

Eligibility

Ages Eligible for Study:	19 Years and older
Genders Eligible for Study:	Both
Accepts Healthy Volunteers:	No

Criteria

Inclusion Criteria:

CKD patients with CKD stage 3 and 4 (eGFR < 60 ml/min and > 15 ml/min per 1.73 m2, not requiring dialysis).
Normal serum phosphate stable over three months (> 0.87 mmol/L and < 1.70 mmol/L)
Not yet following a low phosphate diet as reported by the patient or the renal dietitian (<1500mg/d)
Over 19 years of age

Exclusion Criteria:

Body mass index <20 kg/m2
Current use of phosphate binders or active vitamin D or phenytonin (which induces vitamin D catabolism)
Primary parathyroid defects
Diagnosed osteoporosis
Gut absorption defects
Liver disease
Pregnancy or lactation
Patients hospitalised within the last 4 weeks

Contacts and Locations

Please refer to this study by its ClinicalTrials.gov identifier: NCT00755690

Contacts

Contact: Mhairi Sigrist, MD

604-682-2344 ext 62979

MSigrist@providencehealth.bc.ca

Locations

Canada, British Columbia
St. Paul's Hospital	Recruiting
Vancouver, British Columbia, Canada
Contact: Mhairi Sigrist, MD 604-682-2344 ext 62979 MSigrist@providencehealth.bc.ca

Sponsors and Collaborators

University of British Columbia

Investigators

Principal Investigator:

Adeera Levin, MD

University of British Columbia

More Information

Responsible Party:	University of British Columbia ( Dr. A. Levin )
Study ID Numbers:	H08-01018
Study First Received:	September 17, 2008
Last Updated:	September 18, 2008
ClinicalTrials.gov Identifier:	NCT00755690
Health Authority:	Canada: Health Canada

Keywords provided by University of British Columbia:

Chronic Kidney Disease
CKD
Diet

Dietary Phosphate
Mineral Metabolism
FGF-23

Study placed in the following topic categories:

Renal Insufficiency
Urologic Diseases
Renal Insufficiency, Chronic
Kidney Failure, Chronic

Kidney Diseases
Aluminum Hydroxide
Kidney Failure

ClinicalTrials.gov processed this record on January 13, 2009