Abstract
INTRODUCTION: Hemodialysis patients frequently experience blood pressure fluctuations, which are independently associated with adverse cardiovascular outcomes. However, the optimal dialysate calcium concentration for minimizing blood pressure variability (BPV) remains controversial. METHODS: This retrospective cohort study investigated the differential effects of dialysate calcium concentrations of 1.25 mmol/L (DCa 1.25) versus 1.5 mmol/L (DCa 1.5) on intradialytic BPV. We analyzed 2,061 hemodialysis sessions from 711 maintenance hemodialysis patients across two centers in China. Patients were categorized based on dialysate calcium concentration: 1.25 mmol/L (n = 473 patients, 1,425 sessions) and 1.5 mmol/L (n = 238 patients, 636 sessions). BPV was defined as the difference between maximum and minimum blood pressure during each session. RESULTS: Compared with DCa 1.5, group DCa 1.25 demonstrated significantly lower systolic blood pressure variability (SBPV) (25.23 ± 14.55 vs. 32.42 ± 17.71 mmHg, p < 0.001), diastolic blood pressure variability (DBPV) (9.78 ± 8.07 vs. 11.56 ± 9.67 mmHg, p < 0.001), and mean arterial pressure variability (MAPV) (15.41 ± 9.40 vs. 18.71 ± 11.10 mmHg, p < 0.001). Serum total calcium changes during dialysis were smaller in the 1.25 mmol/L group [0.04 (-0.06, 0.16) vs. 0.15 (0.04, 0.26) mmol/L, p < 0.001] and positively correlated with SBPV and MAPV. In multivariate generalized linear models adjusted for potential confounders, dialysate calcium concentration of 1.5 mmol/L was independently associated with greater BPV. DISCUSSION: These findings suggest that lower dialysate calcium concentration may improve hemodynamic stability during hemodialysis by minimizing calcium flux and associated blood pressure fluctuations.