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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

September 17, 2008
February 17, 2014
September 2008
March 2010   (final data collection date for primary outcome measure)
FGF-23 [ Time Frame: 5 days ] [ Designated as safety issue: No ]
Same as current
Complete list of historical versions of study NCT00755690 on ClinicalTrials.gov Archive Site
Serum calcium, phosphate, PTH, 25 and 1,25 vitamin D and fractional phosphate excretion. [ Time Frame: 5 days ] [ Designated as safety issue: No ]
Same as current
Not Provided
Not Provided
 
Study of Dietary Phosphate and Mineral Homeostasis in Early Chronic Kidney Disease
Study of Dietary Phosphate and Mineral Homeostasis in Early Chronic Kidney Disease

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.

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.
Interventional
Not Provided
Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Crossover Assignment
Masking: Open Label
Primary Purpose: Treatment
Kidney Diseases
  • Behavioral: High/ Low Phosphate diet
    Low phosphate diet (750mg/day).
  • Behavioral: High/ Low Phosphate diet
    Low phosphate diet (750mg/day) with the addition of the phosphate binder aluminum hydroxide (500mg three times per day).
  • Behavioral: High/ Low Phosphate diet
    III. High phosphate diet (2000mg /day).
  • 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.

    Intervention: Behavioral: High/ Low Phosphate diet
  • Active Comparator: 2
    High/ Low Phosphate diet
    Intervention: Behavioral: High/ Low Phosphate diet
  • Active Comparator: 3
    High/ Low Phosphate diet
    Intervention: Behavioral: High/ Low Phosphate diet
Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Completed
32
March 2010
March 2010   (final data collection date for primary outcome measure)

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
Both
19 Years and older
No
Contact information is only displayed when the study is recruiting subjects
Canada
 
NCT00755690
H08-01018
No
University of British Columbia
University of British Columbia
Not Provided
Principal Investigator: Adeera Levin, MD University of British Columbia
University of British Columbia
February 2014

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP