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| Sponsored by: |
Indiana University |
|---|---|
| Information provided by: | Indiana University |
| ClinicalTrials.gov Identifier: | NCT00764816 |
Purpose
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.
| Condition | Intervention |
|---|---|
|
Chronic Kidney Disease |
Other: grain (soy) protein diet Other: casein (meat) protein diet |
| Study Type: | Interventional |
| Study Design: | Basic Science, Randomized, Open Label, Crossover Assignment, Safety/Efficacy Study |
| Official Title: | Effect of Dietary Protein Source on Phosphaturia, PTH and FGF23 in Patients With CKD 3 and 4 |
| Estimated Enrollment: | 9 |
| Study Start Date: | October 2008 |
| Estimated Study Completion Date: | October 2012 |
| Estimated Primary Completion Date: | October 2012 (Final data collection date for primary outcome measure) |
| Arms | Assigned Interventions |
|---|---|
|
1 grain (soy) protein diet:: Active Comparator
The patient is to eat a grain (soy) protein diet for 7 days. The food is prepared by a registered dietitian.
|
Other: grain (soy) protein diet
The patient is to eat a grain (soy) protein diet for 7 days. The food is prepared by a registered dietitian.
|
|
2 casein (meat) protein diet: Active Comparator
The patient is to eat a casein (meat) protein diet for 7 days. The food is prepared by a registered dietitian.
|
Other: casein (meat) protein diet
The patient is to eat a casein (meat) protein diet for 7 days. The food is prepared by a registered dietitian.
|
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 abnormalilties 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
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).
Eligibility| Ages Eligible for Study: | 18 Years and older |
| Genders Eligible for Study: | Both |
| Accepts Healthy Volunteers: | No |
Inclusion Criteria:
Exclusion Criteria:
Contacts and Locations| Contact: Sharon M Moe, MD | 317-278-2868 | smoe@iupui.edu |
| Contact: Miriam P Zidehsarai, MD | 317-274-7097 | mzidehsa@iupui.edu |
| United States, Indiana | |
| Indiana University School of Medicine | Recruiting |
| Indianapolis, Indiana, United States, 46202 | |
| Contact: Sharon M Moe, MD 317-278-2870 smoe@iupui.edu | |
| Contact: Mary A Chambers, RN 317-274-7580 marycham@iupui.edu | |
| Principal Investigator: | Sharon M Moe, MD | Indiana University School of Medicine |
More Information
| Responsible Party: | Indiana University Department of Medicine ( Sharon M. Moe, MD ) |
| Study ID Numbers: | 0807-03 |
| Study First Received: | October 1, 2008 |
| Last Updated: | October 1, 2008 |
| ClinicalTrials.gov Identifier: | NCT00764816 |
| Health Authority: | United States: Institutional Review Board |
|
Chronic kidney disease, stages 3 and 4 phosphaturia phosphorus |
PTH FGF23 Dietary protein source |
|
Renal Insufficiency Metabolic Diseases Phosphate diabetes Kidney Failure, Chronic Metabolism, Inborn Errors Caseins Urologic Diseases |
Genetic Diseases, Inborn Renal Insufficiency, Chronic Hypophosphatemia, Familial Hypophosphatemia Kidney Diseases Metabolic disorder Kidney Failure |
|
Phosphorus Metabolism Disorders Renal Tubular Transport, Inborn Errors Metal Metabolism, Inborn Errors |
