Associations among time-average mineral values, mortality and cardiovascular events in hemodialysis patients

Mineral and bone disease (CKD-MBD), disorders of mineral metabolism, is associated with mortality and cardiovascular disease in dialysis patients. However, the associations among time average mineral values (P, Ca and PTH) and clinical outcomes are not well investigated.

This study examines the associations among mineral values and clinical outcomes from a single medical center.

Adult patients who initiate hemodialysis in Taoyuan General Hospital from 2008 to 2013 were enrolled. We examined these associations using baseline and time-average model. The clinical outcomes included mortality, major adverse cardiovascular events (MACE) and cardiovascular events. We also examined the association between achieve K/DOQI guidelines' targets and clinical outcomes.

From a total of 284 hemodialysis patients, none of the baseline mineral values is associated with mortality and cardiovascular event, except hyperphosphatemia. Compared to patients achieved K/DOQI guidelines' targets, time average hyperphosphatemia is associated with MACE and first cardiovascular event [the adjusted hazard ratios (AHRs) are 6.343 and 3.278); whereas time average hypercalcemia is associated with MACE marginally (the AHR is 5.964). None of above clinical outcomes is related to hyperparathyroidism. The AHRs for mortality in those who only met PTH targets and none of the mineral value targets are 1.73 and 1.74, whereas the AHRs for cardiovascular events in those who met only Ca, only PTH, and none of the targets are 1.73, 1.81 and 2.54 (all ps < 0.05).

Time-average phosphate is associated with cardiovascular events after initiation of dialysis. Among mineral values, serum phosphate is still the strongest predictor for mortality and cardiovascular events.