Treatment of secondary hyperparathyroidism in hemodialyzed patients with high-dose calcium carbonate without vitamin D-3 supplements

Background: Vitamin D compounds are usually indicated for the treatment of secondary hyperparathyroidism in dialysis patients. The possibility to indu ce a reversal of hyperparathyroidism with calcium supplementation alone is controversial. The present study was conducted to assess if oral calcium ca rbonate may constitute a therapeutic option for the control of hyperparathy roidism in patients with high PTH concentrations at the beginning of the tr eatment with chronic hemodialysis. Methods:Thirty-one patients with end-sta ge renal failure with an intact PTH concentration above 250 pg/ml at the be ginning of chronic hemodialysis therapy were treated with high doses of cal cium carbonate; no patient received either aluminium-containing binders or vitamin D compounds. To minimize hypercalcemia, a calcium dialysate concent ration of 2.5 mEq/l was used in all patients. The goal of the study was to reduce the intact PTH concentration to 250 pg/ml with oral calcium carbonat e supplements alone. Results: Throughout the first year on hemodialysis tre atment, the intact PTH concentration decreased from 538 +/- 256 to 251 +/- 218 pg/ml (p < 0.001) By the end of the study, the therapeutic objective wa s achieved in 22 patients (71%) ('responder' group). The remaining 9 patien ts were classified as the 'treatment failure' group. The basal intact PTH c oncentration was not different between both groups (508 +/- 235 vs. 612 +/- 303 pg/ml, respectively, p = n.s.), but 5 'treatment failure' patients adm itted to take a dose of calcium carbonate lower than that prescribed. There were 40 episodes of hyperphosphatemia (11% of all measurements) in 7 of 31 patients, 5 of them belonged to the noncompliance 'treatment failure' pati ents. Only 15 episodes (4% of all measurements) of transient hypercalcemia (range 11.1-11.9 mg/dl) were detected in 8 patients. Conclusions: Secondary hyperparathyroidism in hemodialysis patients can often be reverted by oral calcium carbonate alone. But a good adherence to treatment is absolutely n ecessary.