Dialysis initiation improves calcification propensity

Background. Cardiovascular morbidity and mortality is high in patients starting dialysis and could be related to modifications of calcification inducers and inhibitors by dialysis, promoting cardiovascular events. The impact of dialysis initiation on serum calcification propensity evolution and arterial stiffness is unknown. We therefore prospectively determined the evolution of the one-half maximal transition time (T-50) value and its main determinants as well as pulse wave velocity over the first 3 months of dialysis initiation. Methods. We analysed the evolution of T-50, fetuin-A and mineral metabolism parameters before dialysis initiation (M0) and monthly until Month 3 (M3) in incident patients starting haemodialysis (HD) or peritoneal dialysis (PD) in two tertiary Swiss university hospitals. Arterial stiffness was assessed by pulse tonometry at M0 and M3 and biological parameters were compared between M0 and M3 and before/after HD. Linear mixed models were used to assess parameter evolution over time, taking into account repeated measures and other influencing variables. Results. Forty-six patients on HD and 12 on PD were followed. Among them, 45 were male (78%) with a median age of 67years (25th-75th quartile range 54-77). T-50 significantly increased between M0 and M3 from 183 (120-266) to 246 min (175-330) (P<0.001). Fetuin-A, calcium and magnesium also increased while phosphate decreased. Factors associated with T-50 changes over time were fetuin-A, phosphate and magnesium (P<0.001). Fetuin-A changes were associated with inflammation-related factors (albumin, C-reactive protein) but not calcium and phosphate levels. Arterial stiffness was not significantly modified over 3months. PD and HD initiation showed similar trends. Conclusions. Dialysis initiation significantly improves calcification propensity and fetuin-A levels. These modifications do not explain the high mortality related to dialysis initiation. The clinical relevance of using T-50 values to initiate dialysis awaits further studies.