Cholecalciferol Versus Doxercalciferol in the Treatment of Secondary Hyperparathyroidism in Chronic Kidney Disease
Cholecalciferol Versus Doxercalciferol in the Treatment of Secondary Hyperparathyroidism in Chronic Kidney Disease
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.
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.
Inclusion Criteria:

 -  age 18 years old or older, male or female

 -  able to sign informed consent

 -  CKD stage 3 (GFR 30-59 ml/min) or stage 4 (15-29 ml/min)

 -  intact Parathyroid hormone level (iPTH) > 100 pg/ml for stage 3 or iPTH > 150 pg/ml
 for stage 4

 -  calcidiol levels ≤ 20 ng/ml

 -  ability to ambulate without assistance

 Exclusion Criteria:

 -  intact PTH > 400 pg/ml

 -  initial corrected Calcium > 9.7 mg/dl

 -  initial serum Phosphorous > 5.0 mg/dl

 -  initial standardized blood pressure of > 160/100

 -  history of significant liver disease or cirrhosis

 -  anticipated requirement for dialysis in 6 months

 -  malabsorption, severe chronic diarrhea, or ileostomy

 -  no calcimimetic or active vitamin D therapy 30 days prior to enrollment

 -  use of digoxin, magnesium containing products, mineral oil, or cholestyramine