Dialysis efficacy during acetate-free biofiltration.

levels changed. The observed increase in PTH in the AFB group remains to be clarified. Dialysis eYcacy, Background. Acetate-free biofiltration (AFB) is a haemodiafiltration technique based on continuous measured as KT/V, improved during AFB. post-dilution infusion of a sterile isotonic bicarbonate solution. We performed a long-term randomized pro- acidosis, bicarbonate haemodialysis, calcium‐phosspective trial to compare dialysis eYcacy and metabolic phatebalance, dialysis eYcacy, KT/V, parathormone, control of AFB versus bicarbonate haemodialysis phosphate binders (HD). Methods. The AFB group consisted of 11 and the HD group of nine patients, matched for age, sex and urea reduction rate. Biochemical parameters were obtained Introduction every 3 months for 1 year (haemoglobin, calcium, phosphate, urea, pre- and post-dialysis bicarbonate, Acetate-free biofiltration (AFB) is a haemodiafiltration and parathormone (PTH )) and medication was technique based on continuous post-dilution infusion updated. EYcacy of dialysis calculated by KT/V using of a sterile isotonic bicarbonate solution [1]. Many the dialysate sampling method was determined every studies have outlined that AFB, compared to standard 3 months. In AFB patients, the infusion rate of bicar- bicarbonate dialysis, has great advantages with respect bonate solution was adjusted individually to obtain to acidosis correction because of the individualized bicarbonate values of 22 mmol/l before dialysis and dosing of bicarbonate infusion [2‐6 ]. It has been 32 mmol/l after dialysis. In the HD group, bicarbon- postulated that this improved correction of acidosis ate was added as oral medication to match these should result in better calcium‐phosphate balance [3], bicarbonate concentrations. Statistical analysis was thus decreasing the risk of secondary hyperparathyperformed using ANOVA for repeated measurements. roidism and renal osteodystrophy. However, this could Results. Pre-dialysis serum bicarbonate levels had risen not be confirmed by several short-term prospective to the same extent in both groups at the end of the studies [4,7]. Another described advantage of AFB is study period (AFB from 21.8 to 26.1 mmol/l, that the infusion of a sterile bicarbonate solution [8] P<0.001, and HD from 20.8 to 24.9 mmol/l, avoids the risk of endotoxin and bacterial contaminaP<0.001). Post-dialysis bicarbonate level was higher tion of the bicarbonate concentrate [9]. In addition, in the AFB than in the HD group (P<0.01). Calcium intradialysis occurrence of undesired symptoms, such and phosphate levels remained stable in both groups. as hypotension, muscle cramps and vomiting has PTH increased in both groups (AFB from 10.6 to been reported to decline during treatment with AFB 23.7 pmol/l, and HD from 24.6 to 32.8 pmol/l ), with [10‐12], resulting in better well-being of patients a significant rise only in the AFB patients (P<0.04). [1,10]. One explanation for these dialysis-associated In AFB patients, KT/V increased from 2.73 to 3.17 symptoms could be the acetate present in standard per week (P<0.04). In HD patients KT/V did not bicarbonate haemodialysis (HD), which is completely change (P<0.38); the diVerence between the groups absent in AFB. was significant at the end of the trial (P<0.013). Because many advantages of AFB are claimed, but Finally, haemoglobin levels and erythropoietin dosage no randomized long-term studies have been performed did not change in either group. No significant diVer- to confirm these, we performed a prospective trial of ences between the two groups were observed. 1-year duration comparing AFB with bicarbonate HD. Conclusions. Acidosis was better corrected in AFB without the need for oral supplementation of bicarbonate. However, neither serum calcium nor phosphate Subjects and methods Correspondence and oVprint requests to: A. M. Schrander-v.d. Meer, This study was performed as a single centre trial. The