The Effect of Vitamin D on Urinary Calcium Excretion in Kidney Stone Formers With High Urinary Calcium

Study Overview
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Brief Summary
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The investigators hypothesize that a 3 month course of vitamin D supplementation to treat 25(OH)D deficiency in stone formers with high levels of 24-hour urinary calcium will not increase urinary calcium excretion by greater than 10%.

Detailed Description
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We plan to conduct a clinic-based interventional study of 30 patients followed at Brigham and Women's Hospital with history of nephrolithiasis, urinary calcium excretion between 200 and 400 mg/day, and 25-vitamin D deficiency (defined as serum level ≤ 25ng/ml). The intervention is oral ergocalciferol 50,000 IU per week for 8 weeks [1], and each participant will serve as his own control. The outcome is the change in urinary calcium excretion. The planned study duration is 3 months. We will have greater than 95% power to detect a 10% increase in 24-hour urinary calcium

Official Title
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Phase III Study of the Effect of Vitamin D Repletion on Urinary Calcium Excretion in Kidney Stone Formers With Vitamin D Deficiency and High Urinary Calcium

Conditions
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Vitamin D Deficiency, Nephrolithiasis

Intervention / Treatment
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* Drug: vitamin D (ergocalciferol)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: History of nephrolithiasis 25(OH)D deficiency (defined as serum level ≤ 25ng/ml) within 3 months of enrollment 24-hour urinary calcium excretion > 199 mg/day and < 400 mg/day (measured less than 6 months prior to study enrollment) Exclusion Criteria: Non-Caucasian Women of child-bearing age (age < 50) Known uric acid, cystine, or struvite stone disease Hypercalcemia (serum calcium > 10.4 mg/dl within the past 12 months) Gross hematuria within the past 6 months Acute stone event within the past 2 months Recent stone intervention within the past 1 month Suspected or known secondary causes of hypercalciuria such as primary hyperparathyroidism, sarcoidosis, hyperthyroidism, or malignancy (except non-melanoma skin cancer) Addition or dose change of medicines potentially affecting urinary calcium since enrollment 24-hour urine collection (including diuretics, magnesium supplements, potassium supplements, potassium citrate, and vitamin D supplementation)

Ages Eligible for Study
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Minimum Age: 18 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

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: ergocalciferol<br>After signing informed consent, all participants who meet the study criteria will receive ergocalciferol 50,000 IU weekly for 8 weeks. After completing the ergocalciferol course, participants will take a maintenance dose of cholecalciferol 1,000 IU daily. | Drug: vitamin D (ergocalciferol)<br>* The intervention is oral ergocalciferol 50,000 IU per week for 8 weeks<br>* Other names: ergocalciferol;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Urinary calcium level after treatment with ergocalciferol will be compared with the pre-treatment level. The primary outcome is the change in urinary calcium excretion. |  | 1-2 years | 

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