Dialysis dose and mortality in haemodialysis: is higher better?

BACKGROUND: The effect of dialysis dose on mortality remains unsettled. Current guidelines recommend targeting a single-pool Kt/V (spKt/V) at 1.20-1.40 per thrice-weekly dialysis session. However, the optimal dialysis dose remains mostly disputed. METHODS: In a nationwide registry of all incident patients receiving thrice-weekly haemodialysis, 32 283 patients had available data on dialysis dose, estimated by Kt/V and its variants epuration volume per session (Kt) and Kt indexed to body surface area (Kt/A). Survival was analysed with a multivariate Cox model and a concurrent risk model accounting for renal transplantation. A predictive model of Kt in the upper quartile was developed. RESULTS: Regardless of the indicator, a higher dose of dialysis was consistently associated with better survival. The survival differential of Kt was the most discriminating, but marginally, compared with the survival differential according to Kt/V and Kt/A. Patient survival was higher in the upper quartile of Kt (>69 L/session) then deteriorated as the Kt decreased, with a difference in survival between the upper and lower quartile of 23.6% at 5 years. Survival differences across Kt distribution were similar after accounting for kidney transplantation as a competing risk. Predictive factors for Kt in the upper quartile were arteriovenous fistula versus catheters and graft, haemodiafiltration versus haemodialysis, scheduled dialysis start versus emergency start, long weekly dialysis duration and spKt/V measurement versus double-pool equilibrated Kt/V. CONCLUSIONS: Our data confirm the existence of a relationship between dialysis dose and survival that persisted despite correcting for known confounders. A model for predicting a high dose of dialysis is proposed with practical relevance.

High immunogenicity of a messenger RNA-based vaccine against SARS-CoV-2 in chronic dialysis patients.

BACKGROUND: Patients with chronic kidney disease, dialysis patients and kidney transplant patients are at high risk of developing severe coronavirus disease 2019 (COVID-19). Data regarding the immunogenicity of anti-severe acute respiratory syndrome coronavirus 2 messenger RNA (anti-SARS-CoV-2 mRNA) vaccines in dialysis patients were published recently. We assessed the immunogenicity of anti-SARS-CoV-2 mRNA vaccine in dialysis patients. PATIENTS AND METHODS: One hundred and nine patients on haemodialysis (n = 85) or peritoneal dialysis (n = 24) have received two injections of 30-µg doses of BNT162b2 mRNA COVID-19 vaccine (Pfizer-BioNTech) that were administered intramuscularly 28 days apart. Those who were still seronegative after the second dose were given a third dose 1 month later. Anti-SARS-CoV-2 antibodies were tested before and after vaccination. RESULTS: Ninety-one out of the 102 patients who had at least a 1-month follow-up after the second (n = 97) or the third (n = 5) vaccine doses had anti-SARS-CoV-2 antibodies. The seroconversion rate was 88.7% (86 out of 97 patients) among SARS-CoV-2 seronegative patients at the initiation of vaccination. Receiving immunosuppressive therapy was an independent predictive factor for non-response to vaccination. CONCLUSION: Due to high immunogenicity and safety of mRNA vaccines, we strongly recommend prioritizing a two-dose vaccination of dialysis patients. A third dose can be required in non-responders to two doses. When possible, patients waiting for a kidney transplantation should be offered the vaccine before transplantation.

Is self-care dialysis associated with social deprivation in a universal health care system? A cohort study with data from the Renal Epidemiology and Information Network Registry.

BACKGROUND: Socioeconomic status is associated with dialysis modality in developed countries. The main objective of this study was to investigate whether social deprivation, estimated by the European Deprivation Index (EDI), was associated with self-care dialysis in France. METHODS: The EDI was calculated for patients who started dialysis in 2017. The event of interest was self-care dialysis 3 months after dialysis initiation [self-care peritoneal dialysis (PD) or satellite haemodialysis (HD)]. A logistic model was used for the statistical analysis, and a counterfactual approach was used for the causal mediation analysis. RESULTS: Among the 9588 patients included, 2894 (30%) were in the most deprived quintile of the EDI. A total of 1402 patients were treated with self-care dialysis. In the multivariable analysis with the EDI in quintiles, there was no association between social deprivation and self-care dialysis. Compared with the other EDI quintiles, patients from Quintile 5 (most deprived quintile) were less likely to be on self-care dialysis (odds ratio 0.81, 95% confidence interval 0.71-0.93). Age, sex, emergency start, cardiovascular disease, chronic respiratory disease, cancer, severe disability, serum albumin and registration on the waiting list were associated with self-care dialysis. The EDI was not associated with self-care dialysis in either the HD or in the PD subgroups. CONCLUSIONS: In France, social deprivation estimated by the EDI is associated with self-care dialysis in end-stage renal disease patients undergoing replacement therapy.

Tacrolimus Intrapatient Variability After Switching From Immediate or Prolonged-Release to Extended-Release Formulation, After an Organ Transplantation.

Background and Purpose: Several formulations of tacrolimus are available, but evidence of the benefit of changing to the most recent formulations is lacking. Tacrolimus intra-patient variability (tacrolimus IPV) is an emerging risk factor associated with poor graft outcomes after solid organ transplantations. Here, we examined the modifications of tacrolimus IPV after switching to a different formulation of tacrolimus. Experimental Approach: We identified 353 solid organ transplant recipients that were switched in our center from immediate-release (IR-tacrolimus) or prolonged-release tacrolimus (PR-tacrolimus) to extended-release, LCP-tacrolimus (LCP-tacrolimus). Among them, 54 patients underwent at least 3 available tacrolimus blood concentrations before and after the switch, allowing us to investigate tacrolimus IPV. Key Results: The switch was considered as a safe procedure since only four of the 353 patients presented a graft rejection after the switch, and no patient was hospitalized for tacrolimus overdose. The tacrolimus IPV estimated by the coefficient of variation (CV-IPV) was stable before and after the switch to LCP-tacrolimus (CV-IPV: 29.0% (IQR 25-75 (15.5; 38.5) before and 24.0% (15.8; 36.5) after the switch, p = 0.65). Conclusion and Implications: Switching from IR- or PR-tacrolimus to LCP-tacrolimus is a safe procedure. However, the CV-tacrolimus IPV was not impacted by the change of formulation.

Transonic, thermodilution, or ionic dialysance to manage vascular access: which method is best?

Regularly monitoring blood flow through a vascular access (Qa) can predict a dysfunction and dramatically reduce the number of thromboses. The aim of our study was to compare two integrated access flow devices, thermodilution (Qa-BTM: BTM(®), Fresenius Medical Care, Bad Homburg, Germany) and ionic dialysance (Qa-ID: OCM(®), Fresenius Medical Care, Bad Homburg, Germany), with the "gold standard" saline dilution (Qa-T: Transonic(®), Systems Inc., Ithaca, NY, USA). Measurements were performed sequentially and were repeated in the first 90 minutes of a single dialysis session in 24 long-term hemodialysis patients with a vascular access. Bland-Altman, linear regression (r(2)), and intraclass correlation coefficients (ICC) assessed reproducibility, correlations, and concordance between the techniques. Average access flow for Qa-T was 1549 (± 844) mL/minute, Qa-BTM was 1530 (± 856) mL/minute (P = NS), and Qa-ID was 1619 (± 1085) mL/minute (P = NS). Respectively, ICC, (r(2)), and bias were 0.99, (0.98), and -19 mL/minute for Qa-BTM, and 0.75, (0.65), and +69 mL/minute for Qa-ID. The limits of agreement were -287 to +250 mL/minute for Qa-BTM and -1647 to +1785 mL/minute for Qa-ID. Reproducibility of thermodilution and ionic dialysance, expressed as relative differences, was not significantly different from saline dilution. Recirculation, measured by saline dilution, was 0% (0-4%), the same as the 0% measured by thermodilution, with correct placement of bloodlines and corrected for cardiopulmonary recirculation. The integrated access flow measurement devices, thermodilution and ionic dialysance, are reasonable alternatives to using saline dilution to measure Qa: Thermodilution showed better precision and correlation. They are reliable, make monitoring of vascular access easier, incur no extra costs, and use no additional consumables.