Acetate free citrate-containing dialysate increase intact-PTH and BAP levels in the patients with low intact-PTH

Citrate Dialysate with and without Magnesium Supplementation in Hemodiafiltration: A Comparative Study Versus Acetate

The choice of dialysate buffer in hemodialysis is crucial, with acetate being widely used despite complications. Citrate has emerged as an alternative because of its favorable effects, yet concerns persist about its impact on calcium and magnesium levels. This study investigates the influence of citrate dialysates (CDs) with and without additional magnesium supplementation on CKD-MBD biomarkers and assesses their ability to chelate divalent metals compared to acetate dialysates (ADs). A prospective crossover study was conducted in a single center, involving patients on thrice-weekly online hemodiafiltration (HDF). The following four dialysates were compared: two acetate-based and two citrate-based. Calcium, magnesium, iPTH, iron, selenium, cadmium, copper, zinc, BUN, albumin, creatinine, bicarbonate, and pH were monitored before and after each dialysis session. Seventy-two HDF sessions were performed on eighteen patients. The CDs showed stability in iPTH levels and reduced post-dialysis total calcium, with no significant increase in adverse events. Magnesium supplementation with CDs prevented hypomagnesemia. However, no significant differences among dialysates were observed in the chelation of other divalent metals. CDs, particularly with higher magnesium concentrations, offer promising benefits, including prevention of hypomagnesemia and stabilization of CKD-MBD parameters, suggesting citrate as a viable alternative to acetate. Further studies are warranted to elucidate long-term outcomes and optimize dialysate formulations. Until then, given our results, we recommend that when a CD is used, it should be used with a 0.75 mmol/L Mg concentration rather than a 0.5 mmol/L one.

Regional Citrate Anticoagulation: A Tale of More Than Two Stories

Calcium is a key clotting factor, and several inorganic molecules that bind to calcium have been found to reduce the clotting propensity of blood. Citrate, a calcium chelator, is used as inhibitor of the coagulation cascade in blood transfusion. Also, it is used as an anaticoagulant during dialysis to maintain patency of the extracorporeal circuit, known as regional citrate anticoagulation (RCA). The amount of citrate should be chosen such that ionized calcium concentrations in the extracorporeal circuit are reduced enough to minimize propagation of the coagulation cascade. The dialytic removal of the calcium-citrate complexes combined with reduced ionized calcium concentrations makes necessary calcium supplementation of the blood returning to the patient. This can be achieved in different ways. In classical RCA, citrate and calcium are infused in the afferent and efferent tubing, respectively, whereas the dialysate does not contain calcium. This setup has been shown to be highly efficacious with a very low clotting propensity. Strict monitoring of blood electrolytes is required. Alternatively, the use of a high-calcium dialysate leads to calcium loading, obviating the need for a separate calcium infusion pump. The main advantages are simplified delivery of RCA and less fluctuation of systemic calcium concentrations. Currently, citric acid is sometimes added to the acid concentrate as a replacement for acetic acid. Differences and similarities between RCA and citrate-containing dialysate are discussed. RCA is an excellent alternative to heparin for patients at high risk of bleeding.

Effect of Citrate-Acidified Dialysate on Intact Parathyroid Hormone in Prevalent Hemodialysis Patients: A Matched Retrospective Cohort Study

Background

It has been proposed that substituting citrate-acidified dialysate (CAD) solutions for acetate-acidified dialysate (AAD) could improve hemodynamics and dialysis tolerance and reduce the requirement for systemic anticoagulation. Citrate chelates ionized calcium, but long-term effects of CAD use during maintenance hemodialysis have not been well studied. While many studies of the effects of CAD on serum calcium and intact parathyroid hormone (iPTH) have been short-term or have been limited by sample size, we aimed to determine if there are any long-term (i.e., 6-month) changes from pre-dialysis iPTH levels when patients are switched from AAD to CAD.

Methods

This retrospective cohort study compared various clinical parameters, including pre-dialysis iPTH and serum calcium as well as single pool Kt/V, from eligible patients who received in-center hemodialysis thrice-weekly in geographically matched CAD (n=3) or AAD clinics (n=12). CAD clinics were defined as clinics converting from AAD to CAD if >85% of the patients were prescribed CAD after implementation of CAD within the clinic.

Results

Pre-dialysis iPTH was not significantly different from baseline to 6-month follow-up within either CAD or AAD clinics. Moreover, the mean change from baseline to month 6 in iPTH between patients (n=142) in CAD clinics (−17 pg/mL) and patients (n=671) in AAD clinics (13 pg/mL) was similar (p = 0.24). Likewise, the differences in the mean change in serum calcium concentrations and dialysis adequacy (single pool Kt/V) were not significant between CAD and AAD clinics. For subgroups of patients who were never prescribed cinacalcet or calcium-based phosphate binders, there were no significantly different categorical shifts in iPTH between CAD and AAD clinics.

Conclusion

Similar trends in single pool Kt/V, iPTH, and serum calcium levels were observed in clinics that switched from AAD to CAD versus the geographically matched AAD clinics. These results support CAD as a potential alternative to AAD in hemodialysis.

Comparison between citrate and acetate dialysate in chronic online hemodiafiltration: A short-term prospective study in pediatric settings

BACKGROUND

The use of citrate in chronic hemodialysis to acidify dialysis solutions, in replacement of acetate, began in the 2000's. The purpose of the following study is to determine whether this change represents a better alternative regarding short-term tolerance, efficiency and biocompatibility of chronic renal replacement therapy (RRT) in pediatric patients.

METHODS

A monocentric prospective observational study was conducted in the pediatric dialysis department of Nancy (France) between December 1st, 2014 and January 25, 2015 on a cohort of pediatric patients under predilution on-line hemodiafiltration (olHDF). Sessions were analysed during two study periods of 14 days: a first period during which dialysis solutions were acidified using acetate and a second during which solutes were acidified using citrate. These periods were separated by a washout period of 28 days on citrate solution. Each patient served as his own control.

RESULTS

Dialysis clinical tolerance seems better under citrate regimen, with no statistical significance. No benefit was brought out regarding the prevention of coagulation accidents in the extracorporeal circuit under citrate regimen. The efficiency of olHDF sessions was similar between periods, both in terms of uremic toxins clearance and medium-molecular-weight molecules (MMWM) removal. The evolution of several biological parameters seemed favourable over the citrate period: increase in pre-dialysis serum bicarbonate, stability of plasma hemoglobin and decrease in erythropoietin resistance index (ERI). However, differences in the variation of these parameters between the two periods were not significant. No severe and/or symptomatic hypocalcemia occurred.

CONCLUSION

The use of citrate instead of acetate in dialysis and substitution solutions appears in the short term as a safe alternative for chronic online hemodiafiltration in children.

Long-term effects of citric acid-based bicarbonate haemodialysis on patient outcomes: a survival propensity score–matched study in western France

Background

Citric acid–based bicarbonate haemodialysis (CIT-HD) has gained more clinical acceptance over the last few years in France and is a substitute for other acidifiers [e.g. acetic acid (CH3COOH) and hydrochloric acid (HCl)]. This trend was justified by several clinical benefits compared with CH3COOH as well as the desire to avoid the consequences of the corrosive action of HCl, but a nationwide clinical report raised concerns about the long-term safety of CIT-HD. The aim of this study was to assess the long-term effects of CIT-HD exposure on patient outcomes in western France.

Methods

This is a population-based retrospective multicentre observational study performed in 1132 incident end-stage kidney disease patients in five sanitary territories in western France who started their renal replacement therapy after 1 January 2008 and followed up through 15 October 2018. Relevant data, collected prospectively with the same medical software, were anonymously aggregated for the purposes of the study. The primary goal of this study was to investigate the effects of citrate exposure on all-cause mortality. To provide a control group to CIT-HD one, propensity score matching (PSM) at 2:1 was performed in two steps: the first analysis was intended to be exploratory, comparing patients who received citrate ≤80% of the time (CIT-HD ≤80) versus those who received citrate >80% of the time (CIT-HD >80), while the second analysis was intended to be explanatory in comparing patients with 0% (CIT-HD0) versus 100% citrate time exposure (CIT-HD100).

Results

After PSM, in the exploratory part of the analysis, 432 CIT-HD ≤80 patients were compared with 216 CIT-HD >80 patients and no difference was found for all-cause mortality using the Kaplan–Meier model (log-rank 0.97), univariate Cox regression analysis {hazard ratio [HR] 1.01 [95% confidence interval (CI) 0.71–1.40]} and multivariate Cox regression analysis [HR 1.11 (95% CI 0.76–1.61)] when adjusted for nine variables with clinical pertinence and high statistical relevance in the univariate analysis. In the explanatory part of the analysis, 316 CIT-HD0 patients were then compared with 158 CIT-HD100 patients and no difference was found using the Kaplan–Meier model (log-rank 0.06), univariate Cox regression analysis [HR 0.69 (95% CI 0.47–1.03)] and multivariate Cox regression analysis [HR 0.87 (95% CI 0.57–1.33)] when adjusted for seven variables with clinical pertinence and high statistical relevance in the univariate analysis.

Conclusions

Findings of this study support the notion that CIT-HD exposure ≤6 years has no significant effect on all-cause mortality in HD patients. This finding remains true for patients receiving high-volume online haemodiafiltration, a modality most frequently prescribed in this cohort.

Prospective randomised multicentre study to demonstrate the benefits of haemodialysis without acetate (with citrate): ABC-treat Study. Acute effect of citrate

INTRODUCTION

Dialysis fluid (DF), an essential element in hemodialysis (HD), is manufactured in situ by mixing three components: treated water, bicarbonate concentrate and acid concentrate. To avoid the precipitation of calcium and magnesium carbonate that is produced in DF by the addition of bicarbonate, it is necessary to add an acid. There are 2 acid concentrates that contain acetate (ADF) or citrate (CDF) as a stabilizer.

OBJECTIVE

To compare the acute effect of HD with CDF vs. ADF on the metabolism of calcium, phosphorus and magnesium, acid base balance, coagulation, inflammation and hemodynamic stability.

METHODS

Prospective, multicenter, randomized and crossed study, of 32 weeks duration, in patients in three-week HD, AK-200-Ultra-S or Artis monitor, 16 weeks with ADF SoftPac^®, prepared with 3mmol/L of acetate, and 16 weeks with CDF SelectBag Citrate^®, with 1mmol/L of citrate. Patients older than 18 years were included in HD for a minimum of 3 months by arteriovenous fistula. Epidemiological, dialysis, pre and postdialysis biochemistry, episodes of arterial hypotension, and coagulation scores were collected monthly during the 8 months of the study. Pre and post-dialysis analysis were extracted: venous blood gas, calcium (Ca), ionic calcium (Cai), phosphorus (P), magnesium (Mg) and parathyroid hormone (PTH) among others. ClinicalTrials.gov NCT03319680.

RESULTS

We included 56 patients, 47 (84%) men and 9 (16%) women, mean age: 65.3 (16.4) years, technique HD/HDF: 20 (35.7%)/36 (64.3%). We found differences (p<0.05) when using the DF with citrate (C) versus acetate (A) in the postdialysis values of bicarbonate [C: 26.9 (1.9) vs. A: 28.5 (3) mmol/L], Cai [C: 1.1 (0.05) vs. A: 1.2 (0.08) mmol/L], Mg [C: 1.8 (0.1) vs A: 1, 9 (0.2) mg/dL] and PTH [C: 255 (172) vs. 148 (149) pg/mL]. We did not find any differences in any of the parameters measured before dialysis. Of the 4,416 sessions performed, 2,208 in each group, 311 sessions (14.1%) with ADF and 238 (10.8%) with CDF (p<0.01), were complicated by arterial hypotension. The decrease in maximum blood volume measured by Hemoscan^® biosensor was also lower [-3.4 (7.7) vs -5.1 (8.2)] although without statistical significance.

CONCLUSION

Dialysis with citrate acutely produces less postdialysis alkalemia and significantly modifies Ca, Mg and PTH. CDF has a positive impact on hemodynamic tolerance.

Aortic pulse wave velocity is greater in peritoneal dialysis patients with lower dual energy X-ray absorptiometry (DXA) femoral neck bone mineral density

BACKGROUND

Increased vascular stiffness is associated with low bone mineral density (BMD) in the general population, and both are risk factors for mortality. We wished to determine whether vascular stiffness is associated with BMD in peritoneal dialysis (PD) patients.

METHODS

We measured vascular stiffness by aortic pulse wave velocity (aPWV), BMD by dual electron absorptiometry (DXA) scanning, and body composition using bioimpedance.

RESULTS

We reviewed DXA scans in 125 PD patients, 56.8% male, mean age 64.4 ± 15.3 years, mean aPWV, 10.2 ± 2.6 m/s. We divided patients by aPWV (< 10 and > 10 m/s), and there were no statistical differences in patient demographics, body composition, PD adequacy, peritoneal and urinary calcium losses. On univariate analysis aPWV was negatively associated with total body T score (r = - 0.20, p = 0.037). On multivariable logistic regression patients with higher aPWV were prescribed fewer non-calcium containing phosphate binders, odds ratio (OR) 0.83, 95% confidence interval (CI) 0.70-0.99, p = 0.039, more had lower 25 hydroxy-vitamin D₃ concentrations < 50 ng/L (OR 0.34, CI 0.12-0.93, p = 0.035, and lower femoral BMD OR 0.03 (CI 0-0.3.4), p = 0.029, but there was no association with total or lumbar spine BMD.

CONCLUSION

Our study reinforces the hypothesis of a link between bone disease and vascular disease in dialysis patients. As patients with higher aPWV were prescribed fewer non-calcium containing phosphate binders and fewer had higher 25 hydroxy-vitamin D₃ concentrations, then this raises the possibility that differences in clinical practice and drug prescribing may help to reduce vascular stiffness, which will require testing in future trials.

The effect of citrate dialysate on intradialytic heparin dose in haemodialysis patients: study design of a randomised controlled trial

Background

Unfractionated heparin is the most common anticoagulant used in haemodialysis (HD), although it has many potential adverse effects. Citrate dialysate (CD) has an anticoagulant effect which may allow reduction in cumulative heparin dose (CHD) compared to standard acetate dialysate (AD).

Methods

This double-blinded, randomised, cross-over trial of chronic haemodialysis patients determines if CD allows reduction in CHD during HD compared with AD. After enrolment, intradialytic heparin is minimised during a two-week run-in period using a standardised protocol based on a visual clotting score. Patients still requiring intradialytic heparin after the run-in period are randomised to two weeks of HD with AD followed by two weeks of CD (Sequence 1) or two weeks of HD with CD followed by two weeks of AD (Sequence 2). The primary outcome is the change in CHD with CD compared with AD. Secondary outcomes include metabolic and haemodynamic parameters, and dialysis adequacy.

Discussion

This randomised controlled trial will determine the impact of CD compared with AD on CHD during HD.

Trial registration

ClinicalTrials.gov NCT01466959

Acute effect of citrate bath on postdialysis alkalaemia

INTRODUCTION

The correction of metabolic acidosis caused by renal failure is achieved by adding bicarbonate during dialysis. In order to avoid the precipitation of calcium carbonate and magnesium carbonate that takes place in the dialysis fluid (DF) when adding bicarbonate, it is necessary to add an acid, usually acetate, which is not free of side effects. Thus, citrate appears as an advantageous alternative to acetate, despite the fact that its acute effects are not accurately known.

OBJECTIVE

To assess the acute effect of a dialysis fluid containing citrate instead of acetate on acid-base balance and calcium-phosphorus metabolism parameters.

MATERIAL AND METHODS

A prospective crossover study was conducted with twenty-four patients (15 male subjects and 9 female subjects). All patients underwent dialysis with AK-200-Ultra-S monitor with SoftPac® dialysis fluid, made with 3 mmol/L of acetate and SelectBag Citrate®, with 1 mmol/L of citrate and free of acetate. The following were measured before and after dialysis: venous blood gas monitoring, calcium (Ca), ionic calcium (Cai), phosphorus (P) and parathyroid hormone (PTH).

RESULTS

Differences (p<0.05) were found when using the citrate bath (C) compared to acetate (A) in the postdialysis values of: pH, C: 7.43 (0.04) vs. A: 7.47 (0.05); bicarbonate, C: 24.7 (2.7) vs. A: 27.3 (2.1) mmol/L; base excess (BEecf), C: 0.4 (3.1) vs. A: 3.7 (2.4) mmol/L; corrected calcium (Cac), C: 9.8 (0.8) vs. A: 10.1 (0.7) mg/dL; and Cai, C: 1.16 (0.05) vs. A: 1.27 (0.06) mmol/L. No differences were found in either of the parameters measured before dialysis.

CONCLUSION

Dialysis with citrate provides better control of postdialysis acid-base balance, decreases/avoids postdialysis alkalaemia, and lowers the increase in Cac and Cai. This finding is of special interest in patients with predisposing factors for arrhythmia and patients with respiratory failure, carbon dioxide retention, calcifications and advanced liver disease.