Objective The purpose of the current study was to determine the influence of a 1.75 mmol/L calcium (Ca) concentration dialysate (DCa 1.75) during maintenance hemodialysis (MHD) therapy for patients with chronic kidney disease, mineral, and bone disorders (CKD-MBD) on biochemical indices and clinical prognosis.

Methods Four hundred eighty-three MHD patients from three hemodialysis centers were enrolled. During 24 months of follow-up (January 2011 to December 2012), 289 patients from Center 1 who used 1.50 mmol/L Ca concentration dialysate (Dca 1.50) between January and December 2011 and DCa 1.75 between January and December 2012 were included in the high Ca group. The remaining 194 patients from the other centers who used DCa 1.50 for hemodialysis between January 2011 and December 2012 were included in the ordinary Ca group. The following CKD-MBD biochemical indices were monitored: blood Ca; blood phosphorus (P); intact parathyroid hormone (iPTH); and bone-specific alkaline phosphatase (BAP). The metastatic calcification index included calcification of aortic arch scoring (AoACS), abdominal aorta calcification (AAC), and cardiac valve calcification (CVC). The study end points included all-cause mortality (ACM), cardiovascular and cerebrovascular diseases (CCVDs), fractures, and new metastatic calcifications. The changes between the two groups in the observed indices were compared.

Results Two hundred eighty-four patients in the high Ca group (98.3%) and 194 patients in the ordinary Ca group (100.0%) completed an average follow-up of 21.3±5.6 months. After DCa 1.75 was used, the blood Ca in the high Ca group increased [(2.39±0.22) mmol/L vs. (2.34±0.21) mmol/L, t=−2.910, P=0.004] compared to the previous year, and increased [(2.39±0.22) mmol/L vs. (2.30±0.16) mmol/L, t=5.187, P<0.001] compared to the ordinary Ca group in the same year. The blood P and iPTH decreased [(1.78±0.39) mmol/L vs. (1.89±0.42) mmol/L, t=2.909, P=0.004 and (306.5±298.6) pg/ml vs. (425.7±365.1) pg/ml, t=8.377, P<0.001, respectively] compared with the previous year, and decreased [(1.78±0.39) mmol/L vs (1.86±0.39) mmol/L, t=−2.016, P=0.044 and (306.5±298.6) pg/ml vs. (366.6±341.0) pg/ml, t=−2.113, P=0.035, respectively] compared with the ordinary Ca group in the same year. There was no difference in AoACS between the two groups before and after the change in DCa in the high Ca group (P>0.05). In 2011, there was 13 CCVDs, 2 fractures, and 13 new metastatic calcifications in the ordinary Ca group compared to 8 CCVDs, 3 fractures, and 16 new metastatic calcifications in the high Ca group; there were no statistically significant differences in the incidence of end point events between the two groups (χ²=2.747, P=0.098). In 2012, the values for the ordinary Ca group were 13, 2, and 15, respectively, while the values for the high Ca group were 8, 1, and 19, respectively, which indicated a statistically significant difference in the incidence of end point events between the two groups (χ²=4.391, P=0.036).

Conclusion Short-term use of DCa 1.75 significantly reduced the blood P and iPTH levels in MHD patients, significantly increased the blood Ca level, did not increase the proportion of new cardiovascular calcifications, and decreased the overall incidence of end point events.