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Determining Oral Phosphate Tolerance Across the Spectrum of Glomerular Filtration Rate

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT02672293
Recruitment Status : Unknown
Verified March 2018 by Dr. Rachel Holden, Queen's University.
Recruitment status was:  Recruiting
First Posted : February 3, 2016
Last Update Posted : March 5, 2018
Information provided by (Responsible Party):
Dr. Rachel Holden, Queen's University

Brief Summary:

Over 20 million people in North America (including 2 million Canadians) have chronic kidney disease. These individuals die from diseases of the heart and blood vessels more often than they need dialysis. This is due to hardening of the arteries caused by calcium deposits inside the blood vessel walls. These deposits damage the vessels, causing them to lose flexibility. This makes them unable to respond to the changing demands of the body, and eventually leads to blockages such as stroke and ultimately death.

High levels of phosphate in the blood have been consistently linked to the development of calcium deposits inside blood vessel walls. The kidney is the only organ in the body that can eliminate phosphate that is not required by the body. As kidney function becomes worse, body levels of phosphate increase. However, investigators do not know the time point in the course of kidney disease that problems begin in the way phosphate is eliminated into the urine by the kidneys. Investigators will test the response of the kidneys to a phosphate challenge taken by mouth in subjects who are having accurate measures of kidney function performed by a method called 'inulin clearance'.

The investigators believe that the results of this study will provide important information identifying when investigators should be concerned about body levels of phosphate increasing. This information may lead to changes in the way investigators treat patients by reducing the levels of phosphate in the diet at a much earlier time point then is presently recommended.

Condition or disease Intervention/treatment Phase
Chronic Kidney Disease Drug: Phoslax Not Applicable

Detailed Description:
Fractional excretion of phosphate will be measured pre- and 60 minutes and 120 minutes following an oral challenge of 500 mg of oral phosphate in a group of patients with gold standard measures of glomerular filtration rate.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 50 participants
Allocation: N/A
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Other
Official Title: Determining Oral Phosphate Tolerance Across the Spectrum of Glomerular Filtration Rate
Study Start Date : January 2013
Estimated Primary Completion Date : December 2018
Estimated Study Completion Date : December 2018

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Kidney Diseases

Arm Intervention/treatment
Experimental: Phosphate
500 mg of oral phosphate is administered after an overnight fast.
Drug: Phoslax
Oral sodium phosphate solution (monobasic sodium phosphate 2.4 g and dibasic sodium phosphate 0.9g / 5 mL).
Other Name: Sodium Phosphate

Primary Outcome Measures :
  1. Fractional excretion of phosphate [ Time Frame: Change in fractional excretion of phosphate at 1 and 2 hours ]
    Fractional excretion of phosphate will be measured at baseline and at 1 and 2 hours following a standardized oral phosphate challenge

Secondary Outcome Measures :
  1. Fibroblast growth factor-23 [ Time Frame: Change in level of fibroblast growth factor 23 at 2 hours ]
    Biomarker of phosphate homeostasis

  2. Vitamin D [ Time Frame: Change in level of vitamin D and vitamin D metabolites at 2 hours ]
    Biomarker of phosphate homeostasis

  3. klotho [ Time Frame: Change in level of circulation kloth at 2 hours ]
    Biomarker of phosphate homeostasis

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • stable chronic kidney disease

Exclusion Criteria:

  • unable/unwilling to give informed consent;
  • pregnant or breast-feeding;
  • known allergy to shellfish, iodine or inulin;
  • have evidence of impaired bladder emptying defined as a post-void residual of greater than 20 ml.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT02672293

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Contact: Rachel Holden, MD 613-533-3134

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Canada, Ontario
Kingston General Hospital Recruiting
Kingston, Ontario, Canada, K7L 3V6
Contact: Rachel M Holden, MD    613-533-3134   
Principal Investigator: Rachel M Holden, MD         
Principal Investigator: Christine A White, MD         
Principal Investigator: Michael A Adams, PhD         
Sponsors and Collaborators
Queen's University
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Study Chair: Rachel M Holden, MD Queen's University
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Responsible Party: Dr. Rachel Holden, Principal Investigator, Queen's University Identifier: NCT02672293    
Other Study ID Numbers: Holden/White
Queen's University ( Other Identifier: Queen's University )
First Posted: February 3, 2016    Key Record Dates
Last Update Posted: March 5, 2018
Last Verified: March 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No
Additional relevant MeSH terms:
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Kidney Diseases
Renal Insufficiency, Chronic
Urologic Diseases
Renal Insufficiency