Acetate-free, citrate-Acidified bicarbonate dialysis improves serum calcification propensity-a preliminary study

Background A novel in vitro test (T 50 test) assesses ex vivo serum calcification propensity and predicts mortality in chronic kidney disease and haemodialysis (HD) patients. For the latter, a time-dependent decline of T 50 was shown to relate to mortality. Here we assessed whether a 3-month switch to acetate-free, citrate-Acidified, standard bicarbonate HD (CiaHD) sustainably improves calcification propensity. Methods T 50 values were assessed in paired midweek pre-dialysis sera collected before and 3 months after CiaHD in 78 prevalent European HD patients. In all, 44 were then switched back to acetate. Partial correlation was used to study associations of changing T 50 and changing covariates. Linear mixed effect models were built to assess the association of CiaHD and covariates with changing T 50. Results A significant intra-individual increase of serum calcification resilience was found after 3 months on CiaHD (206±56 to 242±56 min; P < 0.001), but not after switching back to acetate (252±63 to 243±64 min; n = 44; P = 0.29). CiaHD, " serum phosphate and " albumin but not " ionized calcium and magnesium were the strongest determinants of changing T 50. Beneath T 50, only serum albumin but not phosphate changed significantly during 3 months of CiaHD. Conclusion CiaHD dialysis favourably affected calcification propensity as measured by the T 50 test. Whether this treatment, beyond established phosphate-directed treatments, has the potential to sustainably tip the balance towards a more anti-calcific serum milieu needs to be further investigated.