Effects of bone remodelling on calcium mass transfer during haemodialysis.
BACKGROUND
During haemodialysis, calcium balance can affect, or be affected by, mineral metabolism. However, when dialysate calcium concentration (d[Ca]) is chosen or kinetic models are employed to calculate calcium balance, bone remodelling is rarely considered. In this study, we examined whether bone remodelling affects calcium mass transfer during haemodialysis.


METHODS
We dialysed 23 patients using a d[Ca] of 1.0, 1.25, 1.5 or 1.75 mmol/L. Calcium mass transfer was measured and associated with remodelling bone factors.


RESULTS
Calcium balance varied widely depending on the d[Ca]. Calcium removal was -578 +/- 389, -468 +/- 563, +46 +/- 400 and +405 +/- 413 mg when a d[Ca] of 1.0, 1.25, 1.5 or 1.75 mmol/L was used, respectively (1.0 and 1.25 vs 1.5 and 1.75 mmol/L, P < 0.001; 1.5 vs 1.75 mmol/L, P < 0.05). Univariate analysis showed that calcium balance correlated with calcium gradient, parathyroid hormone (PTH), osteocalcin and dialysis vintage. Multivariate analysis revealed that calcium balance was dependent on calcium gradient, PTH and osteocalcin.


CONCLUSIONS
These results suggest that bone remodelling could affect calcium mass transfer during haemodialysis.
Karohl
Cristina
C
Nephrology Division, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
de Paiva Paschoal
Juliana
J
de Castro
Manuel Carlos Martins
MC
Elias
Rosilene Motta
RM
Abensur
Hugo
H
Romão
João Egídio
JE
Passlick-Deetjen
Jutta
J
Jorgetti
Vanda
V
Moysés
Rosa Maria Affonso
RM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D016723:Bone Remodeling; D002118:Calcium / Q000378:metabolism*; D015314:Dialysis Solutions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000097:blood; D006435:Renal Dialysis; D055815:Young Adult
D015314:Dialysis Solutions; D010281:Parathyroid Hormone; D010710:Phosphates; D015675:Osteocalcin; D002118:Calcium