Long-term effects of small doses of calcitriol in hemodialysis patients with moderate secondary hyperparathyroidism

Prevention of secondary hyperparathyroidism (SHPTH) and treatment of the mo derate cases by small p.os doses of Vitamin D has Plot been thoroughly inve stigated on the long term, while large doses of Vitamin D have been success ful in the short term treatment of this entity We administered calcitriol p.os 0.5-1.0 mu g, according to iPTH levels, aft er each dialysis session, in 19 patients (group A) for 36 months They were ten men and nine women, 63 years old (43-81), with iPTH levels > 4N (419 +/ - 185 pg/mL). Seven adenomas were found in five of them (group A1). Serum C a, phosphate (P) and alkaline phosphatase (AP) were measured every 15-30 da ys. Serum iPTH and aluminum as well as echogram or scanning of the parathyr oid glands were checked every 6 months Ten additional dialysis patients, se ven men and three women, 54.5 years old (36-68), non-significantly differen t to group A in iPTH levels (290 +/- 225 pg/mL) with three adenomas in two of them (group B1) received no calcitriol and served as controls (group, B) . Calcitriol treatment significantly lowered serum iPTH levels in group A pat ients (from 419 +/- 185 to 173 +/- 142 pg/mL, p < 0.0001, Delta iPTH: - 246 +/- 161 pg/mL); iPTH remained stable in group B patients (Delta iPTH: +7.9 +/- 116 pg/mL) with an intergroup significant difference at P < 0.0001. Al l other parameters measured did not show any significant change, No signifi cant correlation of iPTH to Ca, P or AP was found in A. Initial iPTH levels were higher in A1 and B1 patients and decreased by calcitriol in A1 group. Adenomas in A1 patients did not change in number and size in contrast to B 1 where new adenomas appeared (5 patients, 10 glands). Small doses of vitamin D lower high iPTH levels and prevent parathyroid gla nd hyperplasia. Existing hypertrophy is stabilized under calcitriol treatme nt both morphologically and biologically.