Citric Acid–Containing Dialysate and Survival Rate in the Dialysis Outcomes and Practice Patterns Study

Abstract

Background: Metabolic acidosis is a common threat for hemodialysis patients, managed by alkaline dialysate. The main base is bicarbonate, to which small amounts of acetic, citric, or hydrochloric acid are added. The first two ones are metabolized to bicarbonate, mostly by the liver. Citric acid-containing dialysate might improve dialysis efficiency, anticoagulation, calcification propensity score, and intradialytic hemodynamic stability. However, a recent report from the French dialysis registry suggested that this dialysate increases mortality risk. This prompted us to assess whether citric acid-containing bicarbonate-based dialysate was associated with mortality in the international Dialysis Outcomes and Practice Patterns Study (DOPPS). Methods: Detailed patient-based information on dialysate composition was collected in DOPPS phases 5 and 6 (2012 to 2017). Cox regression was used to model the association between baseline bicarbonate dialysate containing citric acid versus not containing citric acid and mortality among DOPPS country/phases where citric acid-containing dialysate was used. Results: Citrate-containing dialysate was most commonly used in Japan, Italy, and Belgium (25%, 25%, 21% of DOPPS phase 6 patients) and used in < 10% of patients in other countries. Among 11,306 patients in DOPPS country-phases with at least 15 patients using citrate-containing dialysate, patient demographics, comorbidities, and labs were similar among patients using (14%) vs. not using (86%) citrate-containing dialysate. After accounting for case mix, we did not observe a directional association between citric acid-containing dialysate use (any vs. none) and mortality [HR (95% CI) = 1.14 (0.97-1.34)], nor did we find evidence of a dose-dependent relationship when parameterizing the citrate concentration in the dialysate as 1, 2, and 3+ mEq/L. Conclusions: The use of citric acid-containing dialysate was not associated with greater risk of all-cause mortality in hemodialysis patients participating in DOPPS. Clinical indications for the use of citric acid-containing dialysate deserve further investigation.