Predictive factors for persistent hyperparathyroidism after kidney transplantation

ABSTRACT

A successful kidney transplantation [KT] corrects the main metabolic abnormalities responsible for secondary hyperparathyroidism [HPT]. Nonetheless, after several months, many patients keep abnormally high parathyroid hormone [PTH] levels and/or become hypercalcemic with persistent HPT. In the present survey, the frequency of high PTH levels and the influence of certain important factors on its evolution among patients with successful KT were investigated within three months posttransplantation. A total of 126 patients, who had successful KT, entered the study between 2000 and 2002. On the day of operation and three months later, demographic data and serum calcium, phosphorus, albumin, creatinine, and immunoreactive PTH [iPTH] [by IRMA] were checked. Hypercalcemic patients, at third month, were followed up for one year after transplantation. With respect to the post-KT iPTH level, patients were divided into two groups; those with iPTH above and below 60 pg/mL. The importance of several factors on the evolution of hyperparathyroidism was determined. Sequential changes in serum calcium were also assessed in hypercalcemic patients up to one year after transplantation. Twenty-one [16.6%] out of 126 patients had a post-KT serum calcium of >10.8 mg/mL. Post-KT iPTH value of > 60 pg/mL was found in 9 [7.1%] out of the 126 cases. There was a statistically significant relationship between the age of patients and duration of dialysis and a post- KT high PTH level [P < 0.001]. Other risk factors did not seem to have a significant correlation with the post-KT high PTH level. In all hypercalcemic patients, PTH levels normalized but hypercalcemia persisted in 14 [88%] out of 16 patients up to 1 year after transplantation. Increased age of the patient as well as the duration of dialysis had significant influences on development of persistent HPT, three months posttransplantation. We believe that it is better to transplant the patients as soon as possible, in order to prevent the devastating complication of persistent HPT and hypercalcemia