Impact of incremental versus conventional initiation of haemodialysis on residual kidney function: study protocol for a multicentre feasibility randomised controlled trial

Incremental hemodialysis and vascular access complications: a 12-year experience in a hospital hemodialysis unit

BACKGROUND

Incremental hemodialysis (HD) is considered a valid alternative for patients with residual kidney function. Evidence concerning its effect on vascular access is scarce. We present our 12-year experience of an incremental hemodialysis program with the aim of evaluating survival and complications of arteriovenous fistula in these patients compared to the thrice-weekly scheme.

METHODS

From January 1st, 2006 to December 31st, 2017, 220 incident patients started hemodialysis, 132 (60%) of whom began hemodialysis with two sessions per week and 88 (40%) with three sessions per week. Demographic and clinical variables were assessed at the start of treatment. Data regarding arteriovenous fistula survival and complications were collected.

RESULTS

Both groups had similar baseline sociodemographic and clinical characteristics. A total of 188 (85%) patients were dialyzed with an arteriovenous fistula during follow-up. Eighty-three patients had one or more fistula complications, with no differences between incremental and conventional groups (p = 0.55). Fistula survival rates showed no significant difference between the two groups, whether analyzed from the date of fistula creation (Log Rank p = 0.810) or from the date of initial fistula cannulation (Log Rank p = 0.695).

CONCLUSIONS

We found no differences in arteriovenous fistula survival or complication rate between patients who started HD with an incremental versus a conventional treatment scheme. Randomized controlled clinical trials may be warranted to achieve a higher degree of evidence.

Incremental dialysis: two complementary views

Franco Casino and Mariana Murea discuss today's knowledge about the 'incremental dialysis' concept. Franco Casino frames the problem by saying that, in the presence of substantial residual kidney function, kidney replacement therapy can begin with low doses and/or frequencies, to be gradually increased to compensate for any subsequent losses of residual kidney function, keeping the total clearance above the minimum levels of adequacy. He remarks that studies so far have documented that this approach is safe. He recognizes that adequate randomized controlled trials (RCTs) are necessary to confirm the safety and simplify and standardize the practical aspects of this approach. Mariana Murea objects that most of the evidence gathered so far primarily derives from retrospective and observational studies, which can be influenced by socioeconomic constraints. She argues for the need for RCTs to provide compelling empirical evidence on the efficacy of incremental dialysis. Nephrologists are still reluctant to adopt this approach for various reasons, including unfamiliarity with the method, lack of practical guidance and financial disincentives. Several countries have ongoing or planned RCTs comparing incremental dialysis with conventional dialysis. These trials can shift the haemodialysis paradigm if they validate the safety and effectiveness of this approach. The moderators believe that the results of ongoing trials must be carefully interpreted, and further validation may be needed across different patient populations or healthcare settings. The ultimate goal is to gather robust evidence that could lead to widespread adoption of incremental haemodialysis, optimizing treatment, reducing overtreatment, preserving resources and improving patients' quality of life.

Kidney dysfunction requiring dialysis is a heterogeneous syndrome: we should treat it like one

PURPOSE OF REVIEW

Advanced kidney failure requiring dialysis, commonly labeled end-stage kidney disease or chronic kidney disease stage 5D, is a heterogeneous syndrome -a key reason that may explain why: treating advanced kidney dysfunction is challenging and many clinical trials involving patients on dialysis have failed, thus far. Treatment with dialytic techniques - of which maintenance thrice-weekly hemodialysis is most commonly used - is broadly named kidney 'replacement' therapy, a term that casts the perception of a priori abandonment of intrinsic kidney function and subsumes patients into a single, homogeneous group.

RECENT FINDINGS

Patients with advanced kidney failure necessitating dialytic therapy may have ongoing endogenous kidney function, and differ in their clinical manifestations and needs. Different terminology, for example, kidney dysfunction requiring dialysis (KDRD) with stages of progressive severity could better capture the range of phenotypes of patients who require kidney 'assistance' therapy.

SUMMARY

Classifying patients with KDRD based on objective, quantitative levels of endogenous kidney function, as well as patient-reported symptoms and quality of life, would facilitate hemodialysis prescriptions tailored to level of kidney dysfunction, clinical needs, and personal priorities. Such classification would encourage clinicians to move toward personalized, physiological, and adaptive approach to hemodialysis therapy.

The spectrum of kidney dysfunction requiring chronic dialysis therapy: Implications for clinical practice and future clinical trials

Staging to capture kidney function and pathophysiologic processes according to severity is widely used in chronic kidney disease or acute kidney injury not requiring dialysis. Yet the diagnosis of "end-stage kidney disease" (ESKD) considers patients as a single homogeneous group, with negligible kidney function, in need of kidney replacement therapy. Herein, we review the evidence behind the heterogeneous nature of ESKD and discuss potential benefits of recasting the terminology used to describe advanced kidney dysfunction from a monolithic entity to a disease with stages of ascending severity. We consider kidney assistance therapy in lieu of kidney replacement therapy to better reconcile all available types of therapy for advanced kidney failure including dietary intervention, kidney transplantation, and dialysis therapy at varied schedules. The lexicon "kidney dysfunction requiring dialysis" (KDRD) with stages of ascending severity based on levels of residual kidney function (RKF)-that is, renal urea clearance-and manifestations related to uremia, fluid status, and other abnormalities is discussed. Subtyping KDRD by levels of RKF could advance dialysis therapy as a form of kidney assistance therapy adjusted based on RKF and clinical symptoms. We focus on intermittent hemodialysis and underscore the need to personalize dialysis treatments and improve characterization of patients included in clinical trials.

A multicenter feasibility randomized controlled trial to assess the impact of incremental versus conventional initiation of hemodialysis on residual kidney function

Twice-weekly hemodialysis, as part of incremental initiation, has reported benefits including preservation of residual kidney function (RKF). To explore this, we initiated a randomized controlled feasibility trial examining 55 incident hemodialysis patients with urea clearance of 3 ml/min/1.73 m² or more across four centers in the United Kingdom randomized to standard or incremental schedules for 12 months. Incremental hemodialysis involved twice-weekly sessions, upwardly adjusting hemodialysis dose as RKF was lost, maintaining total (Dialysis+Renal) Std Kt/V above 2. Standard hemodialysis was thrice weekly for 3.5-4 hours, minimum Dialysis Std Kt/V of 2. Primary outcomes were feasibility parameters and effect size of group differences in rate of loss of RKF at six months. Health care cost impact and patient-reported outcomes were explored. Around one-third of patients met eligibility criteria. Half agreed to randomization; 26 received standard hemodialysis and 29 incremental. At 12 months, 21 incremental patients remained in the study vs 12 in the standard arm with no group differences in the urea clearance slope. Ninety-two percent of incremental and 75% of standard arm patients had a urea clearance of 2 ml/min/1.73 m² or more at six months. Serious adverse events were less frequent in incremental patients (Incidence Rate Ratio 0.47, confidence interval 0.27-0.81). Serum bicarbonate was significantly lower in incremental patients indicating supplementation may be required. There were three deaths in each arm. Blood pressure, extracellular fluid and patient-reported outcomes were similar. There was no signal of benefit of incremental hemodialysis in terms of protection of RKF or Quality of Life score. Median incremental hemodialysis costs were significantly lower compared to standard hemodialysis. Thus, incremental hemodialysis appears safe and cost-saving in incident patients with adequate RKF, justifying a definitive trial.

Patiromer in a Patient with Severe Hyperkalemia on Incremental Hemodialysis with 1 Session per Week: A Case Report and Literature Review

Hyperkalemia is common in patients with ESRD, undergoing hemodialysis (HD), and is associated with an increase in hospitalization and mortality. Residual kidney function in long-term dialysis patients is associated with lower morbidity and mortality in HD patients. Although the 2015 National Kidney Foundation-Kidney Disease Outcomes Quality Initiate (NKD-KDOQI) guidelines allow the reduction in the weekly HD dose for patients with a residual kidney urea clearance (Kur) >3 mL/min/1.73 m², very few centers adjust the dialysis dose based on these criteria. In our center, the pattern of incremental hemodialysis (iHD) with once-a-week schedule (1 HD/W) has been an option for a group of patients showing very good results. This pattern is maintained as long as residual diuresis is >1,000 mL/24 h, Kur is >4 mL/min, and there is no presence of edema or volume overload, as well as no analytical parameters persistently outside the advisable range (serum phosphorus >6 mg/dL or potassium [K⁺] >6.5 mmol/L). Management of hyperkalemia in HD patients includes reduction of dietary intake, dosing of medications that contribute to hyperkalemia, and use of cation-exchange resins such as calcium or sodium polystyrene sulfonate. Two newer potassium binders, patiromer sorbitex calcium and sodium zirconium cyclosilicate, have been safely used for potassium imbalance treatment in patients with ESRD in HD with a conventional regimen of thrice weekly, but has not yet been studied in 1 HD/W schedules. We present the case of a 76-year-old woman in iHD (1 HD/W) treated with patiromer for severe HK and describe her clinical characteristics and outcomes. In addition, we review the corresponding literature. Based on these data, it can be anticipated that the use of patiromer may overcome the risk of hyperkalemia in patients with incident ESRD treated with less-frequent HD regimens.

A mixed-method feasibility study of a novel transitional regime of incremental haemodialysis: study design and protocol

Background

Incremental haemodialysis/haemodiafiltration (HD) may help reduce early mortality rates in patients starting HD. This mixed-method feasibility study aims to test the acceptability, tolerance and safety of a novel incremental HD regime, and to study its impact on parameters of patient wellbeing.

Method

We aim to enrol 20 patients who will commence HD twice-weekly with progressive increases in duration and frequency, achieving conventional treatment times over 15 weeks (incremental group). Participants will be followed-up for 6 months and will undergo regular tests including urine collections, bio-impedance analyses and quality-of-life questionnaires. Semi-structured interviews will be conducted to explore patients’ prior expectations from HD, their motivations for participation and experiences of receiving incremental HD. For comparison of safety and indicators of dialysis adequacy, a cohort of 40 matched patients who previously received conventional HD will be constructed from local dialysis records (historical controls).

Results

Data will be recorded on the numbers screened and proportions consented and completing the study (primary outcome). Incremental and conventional groups will be compared in terms of differences in blood pressure control, interdialytic weight changes, indicators of dialysis adequacy and differences in adverse and serious adverse events. In analyses restricted to incremental group, measurements of RRF, fluid load and quality-of-life during follow-up will be compared with baseline values. From patient interviews, a narrative description of key themes along with anonymised quotes will be presented.

Conclusion

Results from this study will address a significant knowledge gap in the prescription HD therapy and inform the development novel future therapy regimens.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10157-021-02072-1.

Renal replacement treatment initiation with twice-weekly versus thrice-weekly haemodialysis in patients with incident dialysis-dependent kidney disease: rationale and design of the TWOPLUS pilot clinical trial

INTRODUCTION

The optimal haemodialysis (HD) prescription-frequency and dose-for patients with incident dialysis-dependent kidney disease (DDKD) and substantial residual kidney function (RKF)-that is, renal urea clearance ≥2 mL/min/1.73 m2 and urine volume ≥500 mL/day-is not known. The aim of the present study is to test the feasibility and safety of a simple, reliable prescription of incremental HD in patients with incident DDKD and RKF.

METHODS AND ANALYSIS

This parallel-group, open-label randomised pilot trial will enrol 50 patients from 14 outpatient dialysis units. Participants will be randomised (1:1) to receive twice-weekly HD with adjuvant pharmacological therapy for 6 weeks followed by thrice-weekly HD (incremental HD group) or outright thrice-weekly HD (standard HD group). Age ≥18 years, chronic kidney disease progressing to DDKD and urine output ≥500 mL/day are key inclusion criteria; patients with left ventricular ejection fraction <30% and acute kidney injury requiring dialysis will be excluded. Adjuvant pharmacological therapy (ie, effective diuretic regimen, patiromer and sodium bicarbonate) will complement twice-weekly HD. The primary feasibility end points are recruitment rate, adherence to the assigned HD regimen, adherence to serial timed urine collections and treatment contamination. Incidence rate of clinically significant volume overload and metabolic imbalances in the first 3 months after randomisation will be used to assess intervention safety.

ETHICS AND DISSEMINATION

The study has been reviewed and approved by the Institutional Review Board of Wake Forest School of Medicine in North Carolina, USA. Patient recruitment began on 14 June 2019, was paused between 13 March 2020 and 31 May 2020 due to COVID-19 pandemic, resumed on 01 June 2020 and will last until the required sample size has been attained. Participants will be followed in usual care fashion for a minimum of 6 months from last individual enrolled. All regulations and measures of ethics and confidentiality are handled in accordance with the Declaration of Helsinki.

TRIAL REGISTRATION NUMBER

NCT03740048; Pre-results.