Vitamin D Deficient Tx Patients Benefit from Oral Cholecalciferol
ISTANBUL—Monthly bolus oral cholecalciferol is a safe and effective treatment for vitamin D repletion in renal transplant patients with longstanding vitamin D deficiency, according to results presented at the 50th Congress of the European Renal Association-European Dialysis and Transplant Association.
“We found that their vitamin D levels tripled over the six-month treatment period,” David J. Goldsmith, MD, Professor of Cardio-Renal Medicine, and Consultant Nephrologist in the Renal Unit at Guy's and St Thomas' NHS Foundation Hospital, London, U.K., noted. “In fact, three quarters of patients in our series achieved a vitamin D level that would put them in the fully vitamin D-sufficient category whereas no patient at the start was anywhere close to vitamin D sufficiency.”
In addition, vitamin D supplementation with cholecalciferol significantly reduced parathroid hormone (PTH) levels and decreased alkaline phosphatase (ALP) to a level that was nearly statistically significant. There were no serious side effects related to treatment.
Dr. Goldsmith emphasized that many more patients need to be followed over a longer time period to determine whether cholecalciferol's favorable effect on bone biochemistry will improve bone quality and decrease fracture rate in transplant patients. “However, this is an important first step,” he said.
The analysis included 54 patients who were alive for at least eight years after receiving their transplant and had chronic low serum vitamin D levels (less than 25 nmol/L). They also had either or both an elevated PTH level or otherwise unexplained proximal myopathy and bone pain.
Vitamin D insufficiency (greater than 25 but less than 50 nmol/L) and deficiency (less than 25 nmol/L) are common in stable ambulatory renal transplant patients and have been associated with adverse skeletal, renal, cardiovascular, and cancer outcomes, Dr. Goldsmith observed. However, a formal repletion randomized, controlled trial with hard endpoints has not been conducted.
The decision to test oral cholecalciferol was based on “practicalities,” he added. “Supplementation with native vitamin D is natural and very cheap and associated with a very good safety profile, all of which are very important in the transplant setting,” he said. “So, as a proof-of-concept investigation, the idea was to determine what effect the supplement had on vitamin D levels and on the parameters that may indicate a beneficial response, specifically, bone markers like PTH and AKP.”
Patients received monthly bolus oral cholecalciferol, 40,000 IU, for a total dose of 240,000 IU over the six-month treatment period. Vitamin D supplementation had minimal effect on calcium and phosphate and no overall effect on renal function.
Dr. Goldsmith pointed out that the cohort represented a typical population of long-term transplant patients with stable graft function.
He said he plans to continue auditing the use of native vitamin D to treat vitamin D deficiency- associated hyperparathyroidism in renal transplant patients, with a goal of demonstrating on bone densitometry that vitamin D supplementation improves skeletal strength and integrity.
“Such improvements have been shown with bone densitometry in patients on steroid withdrawal as well as in patients on bisphosphonate therapy, and we should try it with vitamin D therapy as well,” he observed.
Finally, Dr. Goldsmith said that he believes nephrologists should pay closer attention to vitamin D deficits in their transplant patients. “Nephrologists tend to focus mostly on kidney function in transplant recipients,” he said. “As part of a holistic approach, my view is that you should look at all aspects of their care, including vitamin D and bone health.”