Vitamin D Effect on Calcium Absorption on Persons on Hemodialysis

Study Overview
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Brief Summary
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The assumption has been that 1,25(OH)2D is solely responsible for calcium absorption. That has been one of the presumed causes of hyperparathyroidism in chronic kidney disease (CKD) (low 1,25(OH)2D leads to decreased calcium absorption, which increases parathyroid hormone release in compensation). Replacing 1,25 D directly has been the goal with using 1,25D or its analogues in CKD. There is very little data concerning use of native vitamin D or 25(OH)D in CKD, although autocrine functions in extrarenal tissues would use 25(OH)D. The latest KDIGO guidelines do recognize the autocrine role of vitamin D, but have no data on outcomes or doses or optimal levels to guide them and so have made a blanket recommendation to treat 25D levels in CKD by general healthy population guidelines. This project focuses on an outcome (calcium absorption) that may be impacted by optimizing 25D status in renal patients. The investigators will assume for this project that a level of 25D > 32 ng/ml is optimal in CKD patients as in a healthy population. A secondary outcome is to quantify calcium absorption in CKD patients with and without vitamin D repletion and to quantify systemic 1,25D levels. This may clarify the roles 25D and 1,25D play in calcium absorption.

Official Title
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The Effect of Oral Cholecalciferol (Vitamin D3) on Calcium Absorption in Persons on Long-term Hemodialysis

Conditions
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Chronic Kidney Disease, End Stage Renal Disease, Vitamin D Deficiency

Intervention / Treatment
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* Dietary Supplement: cholecalciferol


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: on hemodialysis > 19 years of age Exclusion Criteria: Pregnancy or planned pregnancy Hypercalcemia (> 10.2 mg/dl) at baseline Chronic GI disease Liver dysfunction Taking steroids Received any investigational drugs within 4 weeks Any allergy to vitamin D3 Chronic vitamin D intake > 1,000 IU daily Dialysate concentration (calcium 2.5mg/L) which is to remain constant during Rx

Ages Eligible for Study
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Minimum Age: 19 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Intervention/Treatment |
| --- |
|Dietary Supplement: cholecalciferol|a weekly dose of 20,000 IU of vitamin D3 will be given orally for 12 weeks.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Vitamin D Status as measured by 25(OH)D levels | A weekly dose of 20,000 IU of vitamin D3 will be taken by the particpant and blood drawn to measure levels at weeks 1, 3, 5, 8, 10, 13, and 18. | 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Calcium Absorption | A calcium absorption test will be done at baseline and after 12 weeks of vitamin D treatment. | 12 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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vitamin D, kidney, renal