ABSTRACT
Uremic patients almost have secondary hyperplasia of the prarathyoid glands. Many clinical trials have demonstrated the benefit of treatment with active vitamin D metabolites. Intravenous preparations seem to be more effective. However, there is paucity of data regarding the effect of various medical therapeutic modalities in uremic patients with severe secondary hyperparathyroidism [HPT]. To evaluate the long-term efficacy of intravenous 1 a-hydroxycholecalciferol [alfacalcidol] treatment in severe secondary HPT, in uremic patients on regular hemodialysis [HD]. Patients and 20 uremic patients on regular HD and suffering from severe secondary HPT were treated by intravenous alfacalcidol after each HD session, thrice weekly, for a period of 2 years. Alfacalcidol doses were carefully titrated according to the biochemical values. The dialysate calcium concentration was set to 1 mmol/l and calcium carbonate tablets were given at doses modulated to guard against hypercalcemic episodes. Patients were subjected to baseline and follow up laboratory tests especially s. intact PTH, s. calcium, s. inorganic phosphorus and s. bone alkaline phosphatase, as well as imaging procedures includinggg U/S examination of the neck, thallium-technetium scintigraphy and plain radiographs of the skeleton. S. intact PTH showed a rebound increase, and reached a mean value comparable to the basesline on the long-term [P=0.895 at 24th month], after an initial response to alfacalcidol therapy. The s. iPTH response to treatment was also heterogeneous and showed no correlation with the given dose. 74% of patients had at least one clinical episode of hypercalcemia versus 65% for hyperphosphatemia. This resulted in limitation of the alfacalcidol dose. The parathyroid gland size at end of study was significantly inccreased compared to the baseline [P=0.042]. Long-term intravenous alfacalcidol pulse therapy was not effective in controlling severe secondary HPT in HD patients. It also failed to correct the increased parathyoid gland size