The aim of this prospective and randomized study was to compare the efficacy, side effects, and costs of 'pulse oral' versus intravenous
calcitriol in the treatment of
secondary hyperparathyroidism in
hemodialysis (HD) patients. A total of 20 patients were randomized to receive over a 4-month period pulse orally administered
calcitriol (pulse oral group; n = 10) or intravenous
calcitriol (intravenous group; n = 10). All patients used standard
dialysate calcium (1.75 mmol/l) throughout the study period. In accordance with the study design
calcium dialysate concentrations were reduced when this was necessary to avoid hypercalcemic crises. The patients were stratified into two subgroups according to their initial serum PTH levels: patients with mild or moderate degree of
hyperparathyroidism (17 patients) and patients with severe
hyperparathyroidism (3 patients). Intravenous and pulse oral cacitriol did not significantly reduce serum PTH concentrations in patients with severe
hyperparathyroidism (1,157 +/- 156 vs. 807 +/- 228 pg/ml [corrected], p = 0.09). Intermittent
calcitriol, administered by intravenous or oral route, significantly reduced serum PTH levels (326 +/- 119 vs. 109 +/- 79 pg/ml [corrected], p = 0.0001) in patients with mild or moderate
hyperparathyroidism. In patients with mild or moderate
hyperparathyroidism, intravenous
calcitriol significantly reduced PTH concentrations at the end of the 1st month, before the increase of serum ionized
calcium levels, whereas 'pulse oral'
calcitriol significantly suppressed parathyroid activity at the end of the 2nd month.
Calcium dialysate concentration was reduced in 9 out of 10 (90%) patients of the pulse oral group and in all patients (10/10) of intravenous group. The incidence of hypercalcemic crises was 24% (39/160) in the pulse oral group and 14% (27/160) in the intravenous group. Analysis of costs showed that intravenous
calcitriol was more expensive compared to pulse oral
calcitriol. These data indicate that intermittent intensive
calcitriol therapy, regardless of the route of administration, is effective in suppressing parathyroid activity in HD patients with mild or moderate
hyperparathyroidism. In contrast, intermittent
calcitriol therapy has a limited ability to achieve sustained serum PTH reductions in HD patients with severe
hyperparathyroidism. Intravenous
calcitriol was more expensive than pulse oral
calcitriol, and we recommend the use of pulse oral
calcitriol in HD patients with mild or moderate
secondary hyperparathyroidism.