Calcium and Phosphorus Balance and Calcium Kinetics in Patients With Stage 3/4 Chronic Kidney Disease

July 22, 2014 updated by: Munro Peacock, Indiana University
The purpose of this study is to gain a better understanding of calcium absorption and metabolism in patients with Chronic Kidney Disease (CKD) using calcium balance and kinetic methods.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The purpose of this study is to gain a better understanding of calcium absorption and metabolism in patients with Chronic Kidney Disease (CKD). It is important that the body get enough calcium to support many important body functions including bone health. CKD changes the calcium balance or how calcium is absorbed and excreted. Because of this, the knowledge of calcium absorption and excretion in patients with normal kidney function cannot be used to assess patients with CKD. In patients with CKD bone heath is often negatively affected due to a combination of poor calcium absorption, increased bone turnover (process where old bone is removed and new bone is formed), increased level of parathyroid hormone (PTH [ a hormone that acts to increase calcium in the blood]) and decrease in vitamin D levels. This negative effect is referred to as Chronic Kidney Disease Mineral Bone Disorder (CKD-MBD).

Treatment to correct CKD-MBD should begin early in the course of CKD. In the normal population calcium supplements are frequently used to help prevent age related bone loss. Calcium supplements can also be used in CKD patients to help bind phosphate. Maintaining correct levels of phosphate in the body is crucial in CKD. However, calcium supplements may have adverse effects by promoting calcium phosphate deposits in soft tissues like the vascular system which could increase the risk of cardiovascular disease.

Therefore this formal balance study is needed to determine if positive calcium balance occurs in patients with advanced CKD who are given calcium with meals as a phosphate binder. This study will also evaluate how the body handles phosphate.

Study Type

Interventional

Enrollment (Actual)

12

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Indiana
      • Indianapolis, Indiana, United States, 46202
        • Indiana University Hospital - Clinical Research Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

35 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  1. Patients with a GFR of < 45 ml/min;
  2. Intact serum PTH > 37 pg/ml;
  3. Age > 35 years (both genders and all races);
  4. Able to perform two three-week balance studies;
  5. Not on oral calcium or vitamin D other than multi vitamin, or willing to stop calcium or vitamin D for one month prior to entry in the study (day 1 of first calcium balance period);
  6. Female patients must be post-menopausal (defined as last menstrual period at least 12 months prior to screening visit) or surgically sterile by hysterectomy;
  7. On stable doses of diuretics, bisphosphonates, anti-epileptics (except dilantin) for at least 2 months.

Exclusion Criteria:

  1. Serious underlying systemic disease (including uncontrolled diabetes, lupus, hypertension, amyloid, etc);
  2. Taking drugs that alter calcium and phosphate balance or homeostasis including high dose cholecalciferol or ergocalciferol (1000 U/day or 50,000U/ wk, respectively), active vitamin D metabolites, calcimimetics, PTH analogues in the last 30 days;
  3. Taking drugs that the investigator feels will alter calcium balance;
  4. Plan to initiate dialysis in the next six months;
  5. Hypercalcemia defined as serum calcium > 10.5 mg/dl;
  6. Hyperphosphatemia defined as serum phosphate >5.5mg/ml;
  7. Intestinal disease that alters absorption or normal intestinal function including celiac disease, small bowel resection, bariatric surgery;
  8. Smoking

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Placebo
Placebo control for calcium carbonate, given in same capsule form as the calcium carbonate, 3 times per day with meals.
Dietary supplement: Placebo
Placebo for calcium carbonate in same capsule form. Given 3 times per day with meals for 21 days in conjunction with a controlled diet.
Active Comparator: Calcium Carbonate (Phosphate Binder)
500 mg elemental calcium as calcium carbonate given 3 times per day with meals for a total of 1500 mg/d elemental calcium.
Dietary supplement: 1500 mg/d elemental calcium as calcium carbonate
500 mg elemental calcium as calcium carbonate given 3 times per day with meals for a total of 1500 mg/d elemental calcium. Given for 21 days in conjunction with a controlled diet.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Calcium Balance
Time Frame: 2 weeks
Calcium balance is measured by dietary calcium intake (mg/d) minus calcium excretion (mg/d) (from both urine and feces).
2 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Phosphorus Balance
Time Frame: 2 weeks
Phosphorus balance is measured by dietary phosphorus intake (mg/d) minus phosphorus excretion (mg/d) from both urine and feces.
2 weeks
"Bone Balance" From Calcium Kinetics
Time Frame: 2 weeks
Calcium kinetics was determined by a calcium radiotracer. Bone balance is the difference between bone formation and bone resorption estimated by calcium kinetic modeling.
2 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Indiana University

Collaborators

Genzyme, a Sanofi Company
Purdue University

Investigators

  • Principal Investigator: Munro Peacock, MD, Indiana University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

June 1, 2010

Primary Completion (Actual)

November 1, 2011

Study Completion (Actual)

November 1, 2011

Study Registration Dates

First Submitted

July 12, 2010

First Submitted That Met QC Criteria

July 12, 2010

First Posted (Estimate)

July 13, 2010

Study Record Updates

Last Update Posted (Estimate)

July 29, 2014

Last Update Submitted That Met QC Criteria

July 22, 2014

Last Verified

July 1, 2014

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Genzyme - 0907-07

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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