Chronic inflammation, which is common in dialysis patients, often causes malnutrition and even protein-energy wasting. However, the association of high-calcium dialysate with malnutrition and/or inflammation in non-diabetic maintenance haemodialysis patients remains unclear. This study investigated the possible adverse effects of high-calcium dialysate and mortality in this population.
A total of 717 non-diabetic haemodialysis patients participated in this 2 year prospective study. The subjects were categorized into three subgroups based on whether dialysate calcium concentrations were high (3.5 mEq/L), standard (3.0 mEq/L) or low (2.5 mEq/L). Demographic, haematological, nutritional and inflammatory markers, biochemical and dialysis-related data were obtained for cross-sectional analysis. Causes of death and mortality rates were also analyzed for each subgroup.
Patients with high-calcium dialysate (n = 82) had a higher incidence of malnutrition and inflammation (61.0% vs 44.1% and 43.9%, respectively) than those with standard- and low-calcium dialysate (n = 528 and 107). Backward stepwise multiple regression analysis revealed that high-calcium dialysate was negatively correlated with nutritional index, serum albumin levels, but positively associated with the inflammatory marker of serum ferritin levels. At the end of the 2 year follow up, 45 patients had died. Cox multivariate analysis demonstrated that high-calcium dialysate was a significant associated factor (relative risk 2.765; 95% confidence interval 1.429-5.352) for 2 year all-cause mortality in these patients.
The analytical results indicate that high-calcium dialysate is associated with malnutrition and inflammation as well as 2 year mortality in non-diabetic maintenance haemodialysis patients and the findings suggest that this population, even those with optimal mineral balance, should avoid high-calcium dialysate.