The Effects of Vitamin D Repletion in Vitamin D Deficient Patients With Stage 3 and 4 Chronic Kidney Disease

This RCT will enroll 74 subjects, men and women over age of 18, with stage 3-4 CKD from various causes including diabetes and hypertension. Patients will be recruited from the Montefiore Medical Center Nephrology clinics and the Montefiore Medical Center internal medicine clinics and other interested individuals. Informed consent will be obtained on all subjects. All subjects with meet with one of the investigators who will verbally explain to them the purpose of the study and the alternatives. Blood and urine tests will be collected to assess for proteinuria, vitamin D levels, serum creatinine, calcium and phosphorus, as well as a urine albumin, calcium and creatinine. These tests will be used for experimental purposes only and will be collected at each study visit over the span of 6 months. There will be two arms, an arm randomized to 50000IU of ergocalciferol once weekly and a placebo arm for 3 months. For an additional 3 months, all patients will be repleted with Vitamin D via open-label extension, based on their levels after 3 months. Secondary outcomes include ambulatory blood pressure monitoring, hemoglobin A1c, HOMA-IR.