Differential effects of phosphate binders on pre-dialysis serum bicarbonate in end-stage kidney disease patients on maintenance haemodialysis.
BACKGROUND
Phosphate binders' constituents have alkalotic or acidotic properties and may contribute to acid base balance in haemodialysis patients. This study aimed to investigate the differential effects of phosphate binders on pre-dialysis serum bicarbonate in End Stage Kidney Disease patients on maintenance haemodialysis.


METHODS
Stable out-patients having satellite haemodialysis for at least 3 months were retrospectively studied for 18 months, excluding those with other medical causes for metabolic acidosis. Blood results were censored for inpatient episodes, at the time of death, renal transplant or dialysis modality change. Multivariable multilevel mixed-effects linear regression was used and five groups of phosphate binders were compared: Group A(Calcium (Ca) and/or Aluminium (Al) binders); B(Sevelamer hydrochloride (SH) alone); C(lanthanum carbonate (LC) alone); D(SH and Ca/Al), E(LC and Ca/Al).


RESULTS
Of 320 patients, 292 were eligible for analysis with a mean follow-up of 15.54 (standard deviation, SD 3.98) months. Similar mean pre-dialysis serum levels of bicarbonate were observed at all 6 month-interval analyses. At 18(th) months, observed mean serum bicarbonate levels in mmol/L were Group B: 21.58 (SD 2.82, P<0.001), C: 23.29 (SD 2.80, P=0.02), D: 21.56 (SD 3.00, P<0.001), and E: 21.29 (SD 3.62, P=0.92) compared with Group A: 22.98 (SD 2.77). Mean serum bicarbonate was related to total SH dose in mmol/L: 22.34 (SD 2.56) for SH <2.5 g/day, 21.61 (SD 2.62) for SH 2.5-4.8 g/day, 21.04 (SD 3.31) for SH >4.8 g/day compared with 22.85 (SD 2.91) for non-users; P-trend<0.001.


CONCLUSIONS
Phosphate binders' constituents may contribute to/protect against a predisposition to pre-dialysis metabolic acidosis. This may be dose dependant in patients taking Sevelamer Hydrochloride.
Department of Nephrology, Western Health, Melbourne, Victoria, Australia. zaw.thet@hotmail.com.
Zaw
Z
Thet
Aung Ko
AK
Win
Eugenie
E
Pedagogos
Jennifer
J
Beavis
Sandra
S
Crikis
Craig
C
Nelson
D000138:Acidosis / Q000097:blood* / Q000175:diagnosis / Q000188:drug therapy* / Q000209:etiology; D000368:Aged; D000369:Aged, 80 and over; D001639:Bicarbonates / Q000097:blood*; D002614:Chelating Agents / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000150:complications / Q000175:diagnosis / Q000534:rehabilitation*; D008297:Male; D010710:Phosphates / Q000627:therapeutic use*; D012189:Retrospective Studies; D016896:Treatment Outcome
D001639:Bicarbonates; D002614:Chelating Agents; D010710:Phosphates