Conditions: Renal Osteodystrophy
Keywords: kidney, parathyroid hormone, vitamin d
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 55
Healthy volunteers: no

Brief summary:
The majority of patients with moderate to severe chronic kidney disease (CKD) (stages 3 and 4) develop secondary hyperparathyroidism (2°HPT), but the optimal therapy to control hyperparathyroidism in this group is unknown. The National Kidney Foundation presented guidelines in 2003 recommending vitamin D supplementation for vitamin D insufficient patients and active vitamin D therapy in patients with sufficient levels. These guidelines are based on opinion since there are no significant trials to determine if vitamin D supplementation is effective in this population. The active vitamin D metabolites doxercalciferol, paricalcitol, and calcitriol have been shown to effectively suppress parathyroid hormone (PTH), but have not been compared with vitamin D supplementation with a calciferol (ergocalciferol or cholecalciferol). Beyond hyperparathyroidism, small studies suggest vitamin D replacement in vitamin D insufficient non-CKD subjects result in improved pain, feeling of well being, blood pressure and strength. In this proposed study we wish to directly compare the effectiveness of cholecalciferol versus doxercalciferol in suppressing elevated PTH levels in subjects with CKD not on dialysis who have vitamin D insufficiency in a three month study. Secondary endpoints will be change in blood pressure.

Detailed description:
Patients with CKD stage 3 were randomly allocated (by blinded group allocation) to either cholecalciferol (4000 U per day for one month then 2000 IU daily thereafter) or doxercalciferol (2.5 mcg po daily. Assessments for blood endpoints (primary end point PTH; secondary calcium, phosphorus) were done monthly. Other assessments (blood pressure) were done at baseline and at 3 months.

Arms:
arm 1: doxercalciferol 1 mcg capsule orally daily for 3 months. This is a form of vitamin D that does not require activation by enzymes in the liver and kidney. arm 2: cholecalciferol 4000 IU capsule orally daily for one month, then 2000 IU capsule daily orally for 2 months. this form of vitamin D requires activation by cells of the body.

Interventions: intervention 1: doxercalciferol intervention 2: Cholecalciferol
Intervention descriptions: intervention 1: form of vitamin D that is already in active form. intervention 2: from of vitamin D that requires cells in the body to make active

Protocol document: