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

Brigham and Women's Hospital

Overview

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%.

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

Study Type

INTERVENTIONAL

Allocation

Purpose

TREATMENT

Masking

NONE

Conditions

Vitamin D Deficiency Nephrolithiasis

Interventions

vitamin D (ergocalciferol)DRUG

The intervention is oral ergocalciferol 50,000 IU per week for 8 weeks

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

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)

Locations (1)

Brigham and Women's Hospital

Boston, Massachusetts, United States

Outcomes

Primary Outcomes

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.

Time frame: 1-2 years

Data from ClinicalTrials.gov

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