Calcium set point progressively worsens in hemodialysis patients despite conventional oral 1-alpha hydroxycholecalciferol supplementation.
Calcium set point was measured in 12 patients on chronic hemodialysis. Dialysate calcium concentration was 1.65 mmol/l. Calcium carbonate (CaCO3) was used as the phosphate binder and oral 1-alpha hydroxycholecalciferol (alfacalcidol) was administered in a dose of 0.25-1.0 micrograms/day for 12 months. Comparing base line and post study values, there were no significant changes in ionized calcium (ICa++), intact immunoreactive parathyroid hormone (iPTH), plasma total calcium (TCa++), plasma phosphate (P), alkaline phosphatase (ALP), or aluminum (Al). However, the relative calcium set point significantly worsened (shifted to the right). Three patients developed hypercalcemia (25%) with a total calcium > 2.65 mmol/l. Total bone mineral content (BMC) fell suggesting demineralization. We conclude that this dose of oral alfacalcidol, CaCO3, and a dialysate calcium concentration of 1.65 mmol/l are not sufficient to halt the progression of secondary hyperparathyroidism in chronic hemodialysis patients. Measurement of calcium set point may be the best early measure of failure to prevent worsening of hyperparathyroidism.
Department of Nephrology and Transplantation, Royal Free Hampstead NHS Trust, London, UK.
A A
AA
Ali
Z
Z
Varghese
J F
JF
Moorhead
R A
RA
Baillod
P
P
Sweny
D000284:Administration, Oral; D015519:Bone Density; D002118:Calcium / Q000097:blood*; D002119:Calcium Carbonate / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D006887:Hydroxycholecalciferols / Q000008:administration & dosage / Q000627:therapeutic use*; D006962:Hyperparathyroidism, Secondary / Q000517:prevention & control*; D007676:Kidney Failure, Chronic / Q000097:blood / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D006435:Renal Dialysis
D006887:Hydroxycholecalciferols; D010281:Parathyroid Hormone; D002119:Calcium Carbonate; D002118:Calcium; C008088:alfacalcidol