Study of Dietary Phosphate and Mineral Homeostasis in Early Chronic Kidney Disease

This study has been completed.
Sponsor:
Information provided by (Responsible Party):
University of British Columbia
ClinicalTrials.gov Identifier:
NCT00755690
First received: September 17, 2008
Last updated: February 17, 2014
Last verified: February 2014
  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

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Crossover Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: Study of Dietary Phosphate and Mineral Homeostasis in Early Chronic Kidney Disease

Resource links provided by NLM:


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 ]

Enrollment: 32
Study Start Date: September 2008
Study Completion Date: March 2010
Primary Completion Date: March 2010 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: 1

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).
Active Comparator: 2
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).
Active Comparator: 3
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 ;

  1. To measure FGF-23 levels before and after a high phosphate diet, low phosphate diet and a low phosphate diet with phosphate binders.
  2. 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
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

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

Locations
Canada, British Columbia
St. Paul's Hospital
Vancouver, British Columbia, Canada
Sponsors and Collaborators
University of British Columbia
Investigators
Principal Investigator: Adeera Levin, MD University of British Columbia
  More Information

No publications provided

Responsible Party: University of British Columbia
ClinicalTrials.gov Identifier: NCT00755690     History of Changes
Other Study ID Numbers: H08-01018
Study First Received: September 17, 2008
Last Updated: February 17, 2014
Health Authority: Canada: Health Canada

Keywords provided by University of British Columbia:
Chronic Kidney Disease
CKD
Diet
Dietary Phosphate
Mineral Metabolism
FGF-23

Additional relevant MeSH terms:
Kidney Diseases
Renal Insufficiency, Chronic
Renal Insufficiency
Urologic Diseases

ClinicalTrials.gov processed this record on October 22, 2014