ST. JOHN'S, NEWFOUNDLAND—Renal transplant recipients who had elevated pre-transplant levels of intact parathyroid hormone (iPTH) are at increased risk of post-transplant hypercalcium and graft rejection, according to findings presented at the Canadian Society of Nephrology's 2012 annual meeting.

“The association of pre-transplant iPTH level with outcome is interesting and clearly suggests mineral metabolism is important in post-transplant outcome,” John Gill, MD said. “The mechanisms which underlie this association need further study.”

Gill, a transplant nephrologist at St. Paul's Hospital in Vancouver, B.C., and his co-investigators made this discovery when gathering information about the increasingly common phenomena of hyperparathyroidism and hypercalcemia in kidney transplant patients. The researchers reviewed information from 1,352 consecutive adults who received kidneys alone between January 2000 an August 2007 in two of Canada's largest transplant centers, St. Paul's Hospital and the Toronto General Hospital.

A “striking” 40 percent of the patients had at least one episode of hypercalcemia—defined as albumin-corrected serum calcium level of 2.6 mmol/L or greater—within a year of transplantation, according to the investigators. Furthermore, 162 patients (12%) had post-transplant hypercalcemia throughout the first post-transplant year. Hypercalcemia resolved within two years in 25 percent of patients with this condition, and it resolved within three and five years post-transplant in 36 percent and 54 percent, respectively, of the affected cohort. Twenty-one (13%) of hypercalcemic patients required surgical parathyroidectomy.

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