Mineral Metabolism and Vascular Effects of Vitamin D Therapy in Kidney Transplant Patients
Mineral Metabolism and Vascular Effects of Vitamin D Therapy in Kidney Transplant Patients
Patients with kidney failure on dialysis can be successfully transplanted. However, many of
 them do not attain a normal kidney function and/or present a slow deterioration of kidney
 function after transplantation. As a consequence, they can develop an endocrine disorder
 called hyperparathyroidism, which can cause bone disease and a high risk of bone fractures.
 In spite of the known bone disease and hyperparathyroidism, there is no well defined
 treatment for these patients.

 Moreover, kidney transplant recipients present a higher mortality rate compared to the
 general population, and the principal cause of death is cardiovascular disease. Dialysis
 patients are known to have extensive cardiovascular calcifications and increased vascular
 stiffness, and these factors have been closely associated with cardiovascular mortality.

 The effect of vitamin D on bone health is well known in the general population. Many studies
 showed a reduction in fracture rate in post-menopausal women and older men receiving vitamin
 D and calcium supplements. Vitamin D analogues are also commonly used to treat
 hyperparathyroidism in dialysis patients. Finally, vitamin D has been suggested to have
 beneficial effects on the cardiovascular system and to reduce mortality in dialysis patients.

 Hectorol® is a vitamin D analog which has been demonstrated to effectively treat
 hyperparathyroidism in dialysis and pre-dialysis patients.

 The effects of vitamin D supplementation on bone disease, hyperparathyroidism and
 cardiovascular function in kidney transplant recipients have not been properly studied.

 Whether Hectorol® therapy helps reducing the severity of bone disease and improving vascular
 function in kidney transplant recipients is still unknown.
The investigators plan to study the cardiovascular and bone effects of Hectorol® in 100
 kidney transplant recipients. The kidney transplant patients will be screened for kidney
 transplant dysfunction and hyperparathyroidism. The study medication will be given to 50
 patients. The other 50 patients will continue to be treated with the actual standard of care
 at the transplant clinic. Subjects will be followed for 18 months and their laboratory
 values, bone density, vascular calcification and stiffness will be collected to see if there
 is an effect of Hectorol® compared to the actual standard of care.
Inclusion Criteria:

 -  Kidney transplant recipient > 18 year/old with reduced and stable kidney function
 (estimated GFR 25-60 ml/min/1.73m2)

 -  iPTH levels between 120 and 500 pg/ml

 -  Stable immunosuppressive therapy (5-10 mg Prednisone/day, stable dosage of calcineurin
 inhibitors, or other immunosuppressive agents for at least 6 months)

 Exclusion Criteria:

 -  Recent rejection episode (< 3 months)

 -  One of the following: baseline estimated GFR>60 ml/min/1.73m2 or <25 ml/min/1.73m2,
 albumin-corrected Ca>9.5 mg/dl or serum phosphorus >4.6 mg/dl.

 -  Recipients of dual transplant organs with exception of kidney-pancreas

 -  Patients already receiving treatment with Vitamin D analogues

 -  Severe peripheral vascular disease or coronary artery disease

 -  History of previous parathyroidectomy

 -  Current alcohol or drug abuse

 -  Pregnant or nursing woman or female of child-bearing age not receiving contraception

 -  Other comorbidities that in the opinion of the investigators would reduce expected
 patient's survival and preclude study completion

 -  Medications that could interfere with Hectorol® metabolism