Abstract / Summary
High dialysate calcium concentration is believed to influence left ventricular ejection fraction (LVEF). We aim to evaluate whether low dialysate calcium (Ca-1.25 mmol/L) is not inferior to high dialysate calcium (Ca-1.75 mmol/L) regarding acute intradialytic changes in LVEF. A randomized, double-blinded, non-inferiority study was conducted in end-stage kidney disease (ESKD) patients undergoing maintenance hemodialysis. Eligible patients were randomized into 2 groups: high dialysate calcium (1.75 mmol/L, the Ca-1.75 group) and low dialysate calcium (1.25 mmol/L, the Ca-1.25 group). The primary endpoint was the acute intradialytic change in LVEF, defined as the change in LVEF between hour 0 (5 min prior to initiation of dialysis) and hour 4 (15 min before cessation of dialysis) during the first dialysis session after randomization. Secondary endpoints included the changes in fibroblast growth factor-23 (FGF-23), C-reactive protein (CRP), blood pressure, and intradialytic hypotension over 24 weeks. Seventy-eight ESKD patients were included (38 assigned to the Ca-1.25 group and 40 to the Ca-1.75 group). The between-group difference in LVEF change (Ca-1.25 minus Ca-1.75) was + 2.0 percentage points (95% CI, − 1.2 to + 5.2), supporting non-inferiority against the prespecified − 5 percentage-point boundary. Serum CRP showed a greater increase in the Ca-1.75 group (p = 0.04), while FGF-23 changes were similar (p = 0.46). Post-dialysis systolic blood pressure was lower in Ca-1.25 (135 ± 18 mmHg versus 146 ± 26 mmHg, p = 0.004). Intradialytic hypotension was more frequent in Ca-1.25 (12.4% versus 6.8%, p = 0.05). Ca-1.25 mmol/L is not inferior to Ca-1.75 mmol/L in terms of acute intradialytic change in LVEF during hemodialysis. Thai Clinical Trials Registry, TCTR20170623001; https://www.thaiclinicaltrials.org/show/TCTR20170623001 (registered 23 June 2017). Low dialysate calcium (1.25 mmol/L) is non-inferior to high calcium (1.75 mmol/L) regarding acute intradialytic changes in left ventricular ejection fraction. High dialysate calcium is associated with higher post-dialysis systolic blood pressure and a lower incidence of intradialytic hypotension. High dialysate calcium increases systemic inflammation without a significant effect on FGF-23 levels.