Effects of haemodialysis and continuous ambulatory peritoneal dialysis on the plasma clearance of an albumin-bound furan dicarboxylic acid.

Organic acids that are strongly bound to albumin are not removed by dialysis and the plasma concentrations of one such substance, a furan dicarboxylic acid (3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid: 5-propyl FPA) have been measured by HPLC in healthy subjects (n = 21), patients on regular haemodialysis (n = 30), and patients treated by continuous ambulatory peritoneal dialysis (n = 21). The mean (+/- SD) concentrations of 5-propyl FPA were significantly higher in haemodialysis (95 +/- 44 microM) compared to CAPD patients (28 +/- 19 microM) and both were higher than in healthy individuals (14 +/- 7 microM). Haemoglobin concentrations in CAPD patients were significantly higher than in those on haemodialysis while these patients had significantly higher albumin concentrations than CAPD patients. The concentration of 5-propyl FPA was positively correlated with the duration of dialysis for haemodialysis patients but not for CAPD patients. The lower concentrations of 5-propyl FPA in CAPD patients may at least partly explain the higher haemoglobin levels found in these patients.