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Chronic Kidney DiseaseNCT00764816

Effect of Dietary Protein Source on Phosphaturia, PTH and FGF23 in Patients With CKD 3 and 4

A study testing grain (soy) protein diet and casein (meat) protein diet in people with Chronic Kidney Disease, run by Indiana University at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

Phosphorus is a substance in the blood that comes from food and is normally cleared from the body by the kidneys. In patients with kidney disease, excess phosphorus may build up in the body as you eat. This leads to problems with bones and blood vessels over time. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Chronic Kidney Disease
What is being tested?
grain (soy) protein diet and casein (meat) protein diet
Could I receive a placebo?
No, everyone receives an active treatment
How many people
9 participants
Where
1 siteUnited States
Study dates
Oct 2008to Feb 2011
Phase
Interventional
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • age >18 years
  • eGFR 20-45 by modified MDRD equation
  • protein/creatinine ratio <5
  • blood pressure <150/95
  • not taking calcium binder or supplements, vitamin D, or phosphate binders
  • normal serum phosphorus and calcium corrected for albumin and intact PTH <100pg/ml
  • medically stable
  • able to give informed consent and come for all visits

Who cannot join

  • history of significant liver disease or cirrhosis
  • medically unstable
  • unable to tolerate diets

Trial locations and contacts

1 site in 1 country.

United States1 site
  • Indiana University School of Medicine

    Indianapolis, Indiana, 46202

Other trials in United States

About this study

Phosphorus is a substance in the blood that comes from food and is normally cleared from the body by the kidneys. In patients with kidney disease, excess phosphorus may build up in the body as you eat. This leads to problems with bones and blood vessels over time. In this study, we will compare the blood and urine before and after eating one week of a diet with a protein from plants (soy and grains) and before and after another one week of diet with protein from animals (meat and dairy products). The amount of phosphorus that the kidney puts out in the urine, and the changes in blood hormones in response to the diet will be measured at the beginning and end of each week on the two diets.

Read the detailed description

Chronic Kidney Disease-Mineral Bone disorder (CKD-MBD) is a constellation of problems related to alterations in mineral and bone homeostasis that occur in CKD stage 3-5D (estimated GFR 60-15 ml/min). The damaged kidney is unable to fully excrete a phosphorus load, leading to a compensatory secondary hyperparathyroidism to attempt to increase urinary phosphorus excretion in order to maintain serum phosphorus in the normal range. Eventually this compensation of elevated PTH becomes pathologic and leads to abnormalities in biochemistries, bone and vascular disease, all of which are associated with morbidity and mortality in patients with CKD. Prevention of these complications is key to improved patient outcomes. Unfortunately, this normal or high normal phosphorus does not reflect the "behind the scenes" appropriate and inappropriate compensation. The use of medication to bind phosphorus from food (phosphate binders) may prevent absorption of phosphorus across the intestine and prevent or change the elevations in PTH and other hormones like FGF23. Thus, either urinary excretion of phosphorus, or changes in hormone may be more appropriate end points to evaluate efficacy of phosphate binders than is serum phosphorus.

In healthy individuals, there is variation throughout the day (diurnal) in serum phosphorus and urine phosphorus excretion, but in dialysis patients, this variability appears to be lost. No data exists for patients with stage 3 and 4 (pre-dialysis) CKD. Intestinal phosphorus absorption is also dependent on bioavailability (amount of free phosphorus available to be absorbed), which differs depending on the protein source, as the phosphorus in grain/soy diets is less bioavailable than that from protein from animal/casein protein source. In our animal model of CKD, these differences in bioavailability impact urinary phosphorus excretion and serum levels of FGF-23, but not PTH. As phosphaturia, PTH, and FGF23 may become important end points for future clinical trials, understanding diurnal variability and the relationship to diet in patients with CKD 3 and 4 with normal serum phosphorus levels is critical. We hypothesize that dietary protein source will affect the hormonal response and diurnal phosphorus homeostasis in advanced CKD. To test this hypothesis, we will examine the following specific aims in a population of CKD stage 3 and 4 subjects from the Indiana University Affiliated Nephrology Clinics and determine

  1. if the dietary protein source affects fasting serum and urinary phosphorus excretion
  2. if the protein source affects post prandial changes in serum and urinary phosphorus in patients
  3. if changes in plasma FGF23 and PTH correlate with urinary phosphorus excretion in response to different protein sources.

We will conduct a cross over study to assess blood and urine after one week of a diet that differs only in the source of the protein (and thus the bioavailability of phosphorus).

Being tested
grain (soy) protein diet, casein (meat) protein diet
Keywords
Chronic kidney disease, stages 3 and 4, phosphaturia, phosphorus, PTH, FGF23, Dietary protein source
Medical subject headings
Renal Insufficiency, Chronic, Hypophosphatemia, Familial

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • grain (soy) protein dietOther

    The patient is to eat a grain (soy) protein diet for 7 days. The food is prepared by a registered dietitian.

  • casein (meat) protein dietOther

    The patient is to eat a casein (meat) protein diet for 7 days. The food is prepared by a registered dietitian.

Study groups in NCT00764816
Study groupRoleWhat they receive
1 grain (soy) protein diet:Active comparatorThe patient is to eat a grain (soy) protein diet for 7 days. The food is prepared by a registered dietitian.
Receives: Other: grain (soy) protein diet
2 casein (meat) protein dietActive comparatorThe patient is to eat a casein (meat) protein diet for 7 days. The food is prepared by a registered dietitian.
Receives: Other: casein (meat) protein diet

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. To determine if the dietary protein source affects fasting serum and urinary phosphorus excretion in patients with CKD stages 3 and 4.

    Measured: 6 months after baseline

Secondary outcomes (2)
  1. To determine if the protein source affects post prandial changes in serum and urinary phosphorus in patients with CKD stages 3 and 4.

    Measured: 6 months from baseline

  2. To determine if changes in plasma FGF23 and PTH correlate with urinary phosphorus excretion in response to different protein sources in patients with CKD stages 3 and 4.

    Measured: 6 months from baseline

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted2 Oct 2008 (estimated)
  2. Study startOct 2008
  3. Primary completionFeb 2011
  4. Study completionFeb 2011

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Basic science
Allocation
Randomised
Intervention model
Crossover
Masking
None (open label)
Enrolment
9 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT00764816
Sponsor's protocol ID
0807-03
Status last verified
Jun 2011
First submitted
1 Oct 2008
Last updated
23 Jun 2011
Results posted
No
Data monitoring committee
No

Publications

  • Moe SM, Zidehsarai MP, Chambers MA, Jackman LA, Radcliffe JS, Trevino LL, Donahue SE, Asplin JR. Vegetarian compared with meat dietary protein source and phosphorus homeostasis in chronic kidney disease. Clin J Am Soc Nephrol. 2011 Feb;6(2):257-64. doi: 10.2215/CJN.05040610. Epub 2010 Dec 23.

    PubMed 21183586

Questions about this trial

What is this clinical trial studying?

A study testing grain (soy) protein diet and casein (meat) protein diet in people with Chronic Kidney Disease, run by Indiana University at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 8 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 23 Jun 2011. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

To determine if the dietary protein source affects fasting serum and urinary phosphorus excretion in patients with CKD stages 3 and 4. (time frame: 6 months after baseline). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT00764816, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Jun 2011.

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