Vitamin D and Arterial Function in Patients With Chronic Kidney Disease

Vitamin D and Arterial Function in Patients With Chronic Kidney Disease

The purpose of this study is to determine whether nutritional (cholecalciferol) or active vitamin D (calcitriol) supplementation improves vascular endothelial function in patients with stage IIIB and IV chronic kidney disease with vitamin D insufficiency or deficiency. The investigators hypothesize that the use of calcitriol supplementation will result in improved vascular endothelial function as compared to cholecalciferol supplementation.

Inclusion Criteria:

• Age ≥ 18 years
• Chronic kidney disease stage IIIB or IV by 4 parameter Modified Diet in Renal Diseases Formula (Estimated Glomerular Filtration Rate [GFR] 44-15 ml/min/1.73m2)
• Vitamin D (D2 + D3) deficient, defined as serum 25(OH)D level < 30 ng/mL
• Corrected serum calcium < 10.2 mg/dL
• Serum phosphate < 4.6 mg/dL
• Serum albumin > 3.0 g/dL
• Body mass index < 40 kg/m2
• Ability to give informed consent

Exclusion Criteria:

• Significant co-morbid conditions that lead the investigator to conclude that life expectancy is less than 1 year
• Expected to undergo living related kidney transplant in next 6 months
• Pregnant, breastfeeding, or unwilling to use adequate birth control
• History of severe liver disease
• Nephrotic range proteinuria (> 3.5 gm/day)
• Use of active vitamin D analogs within 30 days of randomization