Calcium and phosphate balance with quotidian hemodialysis.
BACKGROUND
Conventional hemodialysis (HD) is associated with profound disturbances in calcium and phosphate metabolism and abnormal parathyroid hormone (PTH) levels. Effects of more frequent HD on calcium and phosphate balance have not been fully elucidated.


METHODS
The London Daily/Nocturnal Hemodialysis Study examined effects of quotidian HD, either daily HD (n = 11) or nocturnal HD (n = 12), on calcium and phosphate metabolism, bone alkaline phosphatase levels, and intact PTH (iPTH) levels.


RESULTS
Daily HD patients showed a slight decrease in predialysis serum phosphate levels, no changes in phosphate-binder requirements or serum calcium levels, and slight increases in serum bone alkaline phosphatase and iPTH levels. Nocturnal HD patients showed a trend for decreased predialysis phosphate levels, with significantly lower values than daily HD and matched control patients on conventional HD therapy at several times. Phosphate-binder use by nocturnal HD patients was significantly reduced. Both quotidian HD groups showed decreases in calcium x phosphate product, with significantly lower values for nocturnal HD patients (38.11 mg(2)/dL(2)) compared with daily HD and control patients (53.99 and 52.51 mg(2)/dL(2), respectively) at 18 months. Bone alkaline phosphatase levels increased slightly and attained statistical significance compared with baseline values for both quotidian HD groups. A trend for increases in serum iPTH levels, coupled with increasing levels of bone alkaline phosphatase in nocturnal HD patients, led to the decision to increase the dialysate calcium concentration from 5.0 to 7.0 mg/dL. This 1-time adjustment resulted in a reversal of the trend and a return to baseline values.


CONCLUSIONS
This study shows the superior control of serum phosphate levels in nocturnal HD patients compared with daily HD or conventional HD patients and the benefits of dialysate with a greater calcium concentration in slow nocturnal HD.
Lindsay
Robert M
RM
Optimal Dialysis Research Unit, London Health Sciences Centre, London, Ontario, Canada. robert.lindsay@lhsc.on.ca
Alhejaili
Fayez
F
Nesrallah
Gihad
G
Leitch
Rosemary
R
Clement
Laurie
L
Heidenheim
A Paul
AP
Kortas
Claude
C
D000328:Adult; D000368:Aged; D000469:Alkaline Phosphatase / Q000097:blood; D001071:Appointments and Schedules; D002118:Calcium / Q000378:metabolism*; D002119:Calcium Carbonate / Q000008:administration & dosage; D005260:Female; D005500:Follow-Up Studies; D015312:Hemodialysis Solutions; D006437:Hemodialysis, Home / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000209:etiology; D007527:Isoenzymes / Q000097:blood; D007676:Kidney Failure, Chronic / Q000378:metabolism / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000378:metabolism*; D011446:Prospective Studies; D016896:Treatment Outcome
D015312:Hemodialysis Solutions; D007527:Isoenzymes; D010281:Parathyroid Hormone; D010710:Phosphates; D000469:Alkaline Phosphatase; D002119:Calcium Carbonate; D002118:Calcium