Infrequent dialysis: a new paradigm for hemodialysis initiation

Comparative effectiveness of an individualized model of hemodialysis vs conventional hemodialysis: a study protocol for a multicenter randomized controlled trial (the TwoPlus trial)

BACKGROUND

Most patients starting chronic in-center hemodialysis (HD) receive conventional hemodialysis (CHD) with three sessions per week targeting specific biochemical clearance. Observational studies suggest that patients with residual kidney function can safely be treated with incremental prescriptions of HD, starting with less frequent sessions and later adjusting to thrice-weekly HD. This trial aims to show objectively that clinically matched incremental HD (CMIHD) is non-inferior to CHD in eligible patients.

METHODS

An unblinded, parallel-group, randomized controlled trial will be conducted across diverse healthcare systems and dialysis organizations in the USA. Adult patients initiating chronic hemodialysis (HD) at participating centers will be screened. Eligibility criteria include receipt of fewer than 18 treatments of HD and residual kidney function defined as kidney urea clearance ≥3.5 mL/min/1.73 m2 and urine output ≥500 mL/24 h. The 1:1 randomization, stratified by site and dialysis vascular access type, assigns patients to either CMIHD (intervention group) or CHD (control group). The CMIHD group will be treated with twice-weekly HD and adjuvant pharmacologic therapy (i.e., oral loop diuretics, sodium bicarbonate, and potassium binders). The CHD group will receive thrice-weekly HD according to usual care. Throughout the study, patients undergo timed urine collection and fill out questionnaires. CMIHD will progress to thrice-weekly HD based on clinical manifestations or changes in residual kidney function. Caregivers of enrolled patients are invited to complete semi-annual questionnaires. The primary outcome is a composite of patients' all-cause death, hospitalizations, or emergency department visits at 2 years. Secondary outcomes include patient- and caregiver-reported outcomes. We aim to enroll 350 patients, which provides ≥85% power to detect an incidence rate ratio (IRR) of 0.9 between CMIHD and CHD with an IRR non-inferiority of 1.20 (α = 0.025, one-tailed test, 20% dropout rate, average of 2.06 years of HD per patient participant), and 150 caregiver participants (of enrolled patients).

DISCUSSION

Our proposal challenges the status quo of HD care delivery. Our overarching hypothesis posits that CMIHD is non-inferior to CHD. If successful, the results will positively impact one of the highest-burdened patient populations and their caregivers.

TRIAL REGISTRATION

Clinicaltrials.gov NCT05828823. Registered on 25 April 2023.

The association between dose of hemodialysis and patients mortality in a prospective cohort study

Dialysis adequacy is a known risk factor for mortality in maintenance hemodialysis (MHD) patients. However, the optimal dialysis dose remains controversial. Therefore, we aimed to explore the relationship between dialysis dose and all-cause and cardiovascular disease (CVD) mortality among MHD. We examined the associations of dialysis dose with mortality in a cohort (n = 558) of MHD patients from 31 December 2015 to 31 December 2020. Dialysis adequacy was assessed using baseline Single-pool Kt/V_urea (spKt/V), which was categorized into three groups, and the lowest dose group was used as the reference category. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression models. A total of 214 patients died (64.5% for CVD). Compared with the low-dose group, high-dose group could reduce the risk of all-cause mortality by 33% (HR = 0.67, 95% CI: 0.47–0.98). Of note, when stratification by age, high-dose group was associated with both lower all-cause (HR = 0.46, 95% CI: 0.26–0.81) and CVD mortality (HR = 0.42, 95% CI: 0.20–0.88) among patients with age below 65 years. When stratification by dialysis age, high-dose group was associated with decreased risk of CVD mortality (HR = 0.43, 95% CI: 0.20–0.91) among patients with dialysis age over 60 months. spKt/V is a simple index of hemodialysis dose used in clinical practice and a useful modifiable factor in predicting the risk of death, especially in MHD patients under 65 years old or dialysis age more than 60 months.

Living Well With Kidney Disease and Effective Symptom Management: Consensus Conference Proceedings

Chronic kidney disease (CKD) confers a high burden of uremic symptoms that may be underrecognized, underdiagnosed, and undertreated. Unpleasant symptoms, such as CKD-associated pruritus and emotional/psychological distress, often occur within symptom clusters, and treating 1 symptom may potentially alleviate other symptoms in that cluster. The Living Well with Kidney Disease and Effective Symptom Management Consensus Conference convened health experts and leaders of kidney advocacy groups and kidney networks worldwide to discuss the effects of unpleasant symptoms related to CKD on the health and well-being of those affected, and to consider strategies for optimal symptom management. Optimizing symptom management is a cornerstone of conservative and preservative management which aim to prevent or delay dialysis initiation. In persons with kidney dysfunction requiring dialysis (KDRD), incremental transition to dialysis and home dialysis modalities offer personalized approaches. KDRD is proposed as the preferred term given the negative connotations of "failure" as a kidney descriptor, and the success stories in CKD journeys. Engaging persons with CKD to identify and prioritize their personal values and individual needs must be central to ensure their active participation in CKD management, including KDRD. Person-centered communication and care are required to ensure diversity, equity, and inclusion; education/awareness that considers the health literacy of persons with CKD; and shared decision-making among the person with CKD, care partners, and providers. By putting the needs of people with CKD, including effective symptom management, at the center of their treatment, CKD can be optimally treated in a way that aligns with their goals.

Incremental Hemodialysis: What We Know so Far

Traditionally, patients that develop progressive chronic kidney disease in need of kidney replacement therapy are prescribed thrice weekly in-center hemodialysis sessions at the beginning of therapy. This empiric prescription is based on historic trials that were comprised of mostly prevalent patients. Incremental hemodialysis is the process of performing <3 sessions of dialysis per week or limiting dialysis dose by duration at the initial onset of treatment to provide a more gradual transition, mimicking the progressive nature of kidney disease. Adding clearance contributions from residual kidney function is the standard of care with peritoneal dialysis but has not routinely been employed with hemodialysis. Accounting for residual kidney function accompanied by improvement in adjuvant pharmacotherapy, such as newer potassium binding agents and dietary modification, can augment dialytic clearances and allow for an incremental approach. Utilizing incremental dialysis has been associated with both preserving residual kidney function as well as improving patient quality of life. Barriers to this approach include concerns regarding patient acceptance of dialysis prescription changes, adherence to therapy, and provider factors that would require a restructuring of the current thrice weekly hemodialysis rubric. Candidacy for incremental therapy has shown the best outcomes when urea clearances exceed 3 mL/min and urine volumes are >500 mL/day, although these measures have been deemed conservative. A significant amount of retrospective and registry data has been supportive of initiating incremental hemodialysis and several pilot studies have shown the feasibility of implementing such an approach. Larger, randomized control trials are needed to fully evaluate safety and efficacy to allow for more widespread acceptance of this patient-centered approach to chronic kidney disease.

Benefits of Incremental Hemodialysis Seen in a Historical Cohort Study

Purpose

Previous research on incremental hemodialysis transition has mainly focused on one or two benefits or prognoses. We aimed to conduct a comprehensive analysis by investigating whether incremental hemodialysis was simultaneously associated with adequate dialysis therapy, stable complication indicators, long-lasting arteriovenous vascular access, and long-lasting preservation of residual kidney function (RKF) without increasing mortality or hospitalization.

Patients and Methods

Incident hemodialysis patients from Huashan Hospital in Shanghai, China, over the period of 2012 to 2019, were enrolled and followed every three months until death or the time of censoring. Changes in complication indicators from baseline to all post-baseline visits were analyzed by mixed-effects models. The outcomes of RKF loss, arteriovenous vascular access complications, and the composite of all-cause mortality and cardiovascular events were compared between incremental and conventional hemodialysis by Cox proportional hazards model.

Results

Of the 113 patients enrolled in the study, 45 underwent incremental and 68 conventional hemodialysis. There were no significant differences in the changes from baseline to post-baseline visits in complication indicators between the two groups. Incremental hemodialysis reduced the risks of RKF loss (HR, 0.33; 95% CI, 0.14–0.82), de novo arteriovenous access complication (HR, 0.26; 95% CI, 0.08–0.82), and recurrent arteriovenous access complications under the Andersen–Gill (AG) model (HR, 0.27; 95% CI, 0.10–0.74) and the Prentice, Williams and Peterson Total Time (PWP-TT) model (HR, 0.31; 95% CI, 0.12–0.80). There were no significant differences in all-cause hospitalization or the composite outcome between groups.

Conclusion

Incremental hemodialysis is an effective dialysis transition strategy that preserves RKF and arteriovenous access without affecting dialysis adequacy, patient stability, hospitalization risk and mortality risk. Randomized controlled trials are warranted.

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.

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.

Novel conservative management of chronic kidney disease via dialysis-free interventions

PURPOSE OF REVIEW

In advanced chronic kidney disease (CKD) patients with progressive uremia, dialysis has traditionally been the dominant treatment paradigm. However, there is increasing interest in conservative and preservative management of kidney function as alternative patient-centered treatment approaches in this population.

RECENT FINDINGS

The primary objectives of conservative nondialytic management include optimization of quality of life and treating symptoms of end-stage renal disease (ESRD). Dietetic-nutritional therapy can be a cornerstone in the conservative management of CKD by reducing glomerular hyperfiltration, uremic toxin generation, metabolic acidosis, and phosphorus burden. Given the high symptom burden of advanced CKD patients, routine symptom assessment using validated tools should be an integral component of their treatment. As dialysis has variable effects in ameliorating symptoms, palliative care may be needed to manage symptoms such as pain, fatigue/lethargy, anorexia, and anxiety/depression. There are also emerging treatments that utilize intestinal (e.g., diarrhea induction, colonic dialysis, oral sorbents, gut microbiota modulation) and dermatologic pathways (e.g., perspiration reduction) to reduce uremic toxin burden.

SUMMARY

As dialysis may not confer better survival nor improved patient-centered outcomes in certain patients, conservative management is a viable treatment option in the advanced CKD population.

Twice weekly hemodialysis is safe at the beginning of kidney replacement therapy: the experience of the Nephrology Department at Hedi Chaker University Hospital, Sfax, south of Tunisia

We re-examine the infrequent paradigm of a biweekly dialysis at the start of renal replacement therapy. The current method is to launch hemodialysis among patients using a 'full-dose' posology three times a week. As a matter of fact, recent data has suggested that frequent hemodialysis leads to high mortality at the onset of dialysis. The aim of our study is to show the factors affecting early mortality especially the hemodialysis frequency. We undertook an observational study in the hemodialysis unit of Sfax University Hospital (south Tunisia). We enrolled the incident patients during one year. Baseline demographic and clinical characteristics of patients were noted. The survival status of each patient is observed at 6 months after the onset of hemodialysis. We analyzed the factors associated with mortality, especially the hemodialysis frequency (twice or thrice weekly hemodialysis regimen). We enrolled 88 patients with mean age of 56 ± 18 years old. Thirty patients underwent twice weekly dialysis (Group 1) and 58 patients underwent thrice weekly dialysis (Group 2). The mortality at 6 months was similar in the 2 groups (the rate of death = 30% in group 1 vs 13.8% in group 2, p = 0.07). However, the mortality was lower in the group with preserved residual diuresis (35.3% vs 64.7% in the group without residual diuresis, p = 0.02). The mortality was higher in diabetes patients (64.7% vs 35.5%, p = 0.02). It was concluded that twice or threefold weekly treatment have some considerable similar outcomes on the patients survival (at 6 months).

Residual Urine Output and Mortality in a Prospective Hemodialysis Cohort

Introduction

Although residual urine output (UOP) is associated with better survival and quality of life in dialysis patients, frequent measurement by 24-hour urine collection is burdensome. We thus sought to examine the association of patients’ self-reported residual UOP, as an alternative proxy of measured residual UOP, with mortality risk in a prospective hemodialysis cohort study.

Methods

Among 670 hemodialysis patients from the prospective multicenter Malnutrition, Diet, and Racial Disparities in Kidney Disease study, we examined associations of residual UOP, ascertained by patient self-report, with all-cause mortality. Patients underwent protocolized surveys assessing presence and frequency of UOP (absent, every 1–3 days, >1 time per day) every 6 months from 2011 to 2015. We examined associations of baseline and time-varying UOP with mortality using Cox regression.

Results

In analyses of baseline UOP, absence of UOP was associated with higher mortality in expanded case-mix adjusted Cox models (ref: presence of UOP): hazard ratio (HR), 1.78 (95% confidence interval [CI], 1.16–2.72). In analyses examining baseline frequency of UOP, point estimates suggested a graded association between lower frequency of UOP and higher mortality, although estimates for UOP every 1 to 3 days did not reach statistical significance (reference: UOP >1 time per day): HR, 1.29 (95% CI, 0.82–2.05) and HR, 1.97 (95% CI, 1.24–3.12) for UOP every 1 to 3 days and absence of UOP, respectively. Similar findings were observed in analyses of time-varying UOP.

Conclusion

In hemodialysis patients, there is a graded association between lower frequency of self-reported UOP and higher mortality. Further studies are needed to determine the clinical impact of more frequent assessment of residual UOP using self-reported methods.

Impact of twice- or three-times-weekly maintenance hemodialysis on patient outcomes: A multicenter randomized trial

AIM

Maintenance hemodialysis (MHD) frequency is associated with survival and complication rates. Achieving the optimal balance between healthcare, quality of life (QOL), and medical costs is challenging. We compared complications, inflammatory status, nutritional status, and QOL between patients with different MHD frequencies.

MATERIAL AND METHODS

This was a multicenter randomized trial of patients treated between May 2011 and August 2017 at 3 tertiary hospitals in Wenzhou. Patients were grouped according to their treatment schedule over 1 year: twice-weekly or 3-times-weekly. Complications, biochemistry parameters, and QOL (KDQOL-SFTM 1.3 scale) were assessed.

RESULTS

One hundred forty patients were included aged 29 to 68 years (mean age, 50.9 ± 4.3 years). There were no significant differences in infection, heart failure, or cerebral hemorrhage complications between the 2 groups (P = .664). Pre-dialysis hemoglobin, high-sensitivity C-reactive protein, serum albumin, total cholesterol, triglyceride, calcium, phosphate, parathyroid hormone, and ejection fraction were similar in both groups (P > .05). After 1 year of MHD, both groups exhibited significant improvements in these parameters (all P < .05) with no significant differences between groups. Serum creatinine, blood urea nitrogen (BUN), and weekly standard hemodialysis treatment adequacy did not improve after treatment (all P > .05), although a difference in BUN was observed between the 2 groups (P < .001). QOL was superior in the twice-weekly group than in the 3-times-weekly group (all P < .05), except for social support, which was slightly better in the 3-times-weekly group than in the twice-weekly group.

CONCLUSIONS

Twice- and 3-times-weekly MHD resulted in comparable inflammatory and nutritional clinical outcomes and adverse events. QOL was better for the twice-weekly schedule. Even for patients with economic constraints, twice- or 3-times-weekly MHD should be selected with caution after consideration of BUN levels at baseline.

Initiating renal replacement therapy through incremental haemodialysis: Protocol for a randomized multicentre clinical trial

Background

Thrice-weekly haemodialysis is the usual dose when starting renal replacement therapy; however, this schedule is no longer appropriate since it does not consider residual renal function. Several reports have suggested the potential benefit of beginning haemodialysis less frequently and incrementally increasing the dose as the residual renal function decreases. However, all the data published so far are from observational studies. Thus, this clinical trial avoids any potential selection bias and will assess the possible benefits that have been observed in observational studies.

Methods/design

This report describes the study protocol of a randomized prospective multi-centre open-label clinical trial to evaluate whether starting renal replacement therapy with twice-weekly haemodialysis sessions preserves residual renal function better than the standard thrice-weekly regimen. We also explore other clinical parameters, such as concentrations of uremic toxins, dialysis doses, control of anaemia, removal of medium-weight uremic toxins, nutritional status, quality of life, hospital admissions and mortality. Only incident haemodialysis patients who can maintain a urea clearance rate KrU ≥ 2.5 mL/min/1.73 m² are eligible. Patient recruitment began on 1 January 2017 and will last for 2 years or until the required sample size has been recruited to ensure the established statistical power has been reached. The minimum follow-up period will be 1 year. Anuric patients with acute renal failure and patients who return to haemodialysis after a kidney transplant failure are excluded. It has been calculated that 44 patients should be recruited into each group to achieve a power of 80% in a two-sided comparison of means with a usual significance level of 0.05. A time-to-event analysis will estimate the probability of kidney function survival in both groups using the Kaplan–Meier method. Survival curves will be compared with log-rank tests. This survival analysis will be complemented with a proportional hazard model to estimate the hazard ratio of kidney function survival adjusted for any confounding factors. Analyses will be carried out in accordance with the intention-to-treat principle.

Discussion

The incremental initiation of dialysis may preserve residual renal function better than the conventional treatment, with similar or higher survival rates, as reported by observational studies. To our knowledge, this is the first clinical trial to evaluate whether initiating renal replacement therapy with twice-weekly haemodialysis sessions preserves residual renal function better than beginning with the standard thrice-weekly regimen.

Trial registration

ClinicalTrials.gov, NCT03302546. Registered on 5 October 2017.

Hemodynamic and Laboratory Changes during Incremental Transition from Twice to Thrice-Weekly Hemodialysis

OBJECTIVE

Incremental hemodialysis (HD) is a strategy utilized to gradually intensify dialysis among patients with incident end-stage renal disease. However, there are scarce data about which patients' clinic status changes by increasing treatment frequency.

METHODS

We retrospectively examined statistically de-identified data from 569 patients who successfully transitioned from twice- to thrice-weekly HD (2007-2011) and compared the differences in monthly-averaged values of hemodynamic and laboratory indices during the 3 months before and after the transition with the values at 1 month prior to transition serving as the reference.

RESULTS

At 3 months after transitioning from twice- to thrice-weekly HD, ultrafiltration volume decreased by 0.5 (95% CI 0.3-0.6) L/session among 189 patients (33%) with weekly interdialytic weight gain (IDWG) ≥5.4 kg/week, and increased by 0.4 (95% CI 0.3-0.5) L/session among 186 patients (33%) with weekly IDWG <3.3 kg/week. Weekly IDWG consistently increased after the transition irrespective of baseline values (1.7 [95% CI 1.5-1.9] kg/week). Pre-HD systolic blood pressure (SBP) decreased by 12 (95% CI 9-14) mm Hg among 177 patients (31%) with baseline pre-HD SBP ≥160 mm Hg, which coincided with a decreasing trend in post-HD body weight (1.3 [95% CI 0.8-1.7] kg).

DISCUSSION

In conclusion, patients who increased HD frequency from twice to thrice weekly treatment experienced increased weekly IDWG and better pre-HD SBP control with lower post-HD body weight.

Narrative Review of Incremental Hemodialysis

The prescription of hemodialysis (HD) in patients with incident end-stage kidney disease (ESKD) is fundamentally empirical. The abrupt transition from nondialysis chronic kidney disease (CKD) to thrice-weekly in-center HD of much the same dialysis intensity as in those with prevalent ESKD underappreciates the progressive nature of kidney disease whereby the decline in renal function has been gradual and ongoing-including at the time of HD initiation. Adjuvant pharmacologic treatment (i.e., diuretics, acid buffers, potassium binders), coupled with residual kidney function (RKF), can complement an initial HD regimen of lower intensity. Barriers to less intensive HD in incident ESKD include risk of inadequate clearance of uremic toxins due to variable and unexpected loss of RKF, lack of patient adherence to assessments of RKF or adjustment of HD intensity, increased burden for all stakeholders in the dialysis units, and negative financial repercussions. A stepped dialysis regimen with scheduled transition from time-delineated twice-weekly HD to thrice-weekly HD could represent an effective and safe strategy to standardize incremental HD in patients with CKD transitioning to early-stage ESKD. Patients' adherence and survival as well as other clinical outcomes should be rigorously evaluated in clinical trials before large-scale implementation of different incremental schedules of HD. This review discusses potential benefits of and barriers to alternative dialysis regimens in patients with incident ESKD, with emphasis on twice-weekly HD with pharmacologic therapy, and summarizes in-progress clinical trials of incremental HD schedules.

Impact of residual kidney function on hemodialysis adequacy and patient survival

Background

Both dialysis dose and residual kidney function (RKF) contribute to solute clearance and are associated with outcomes in hemodialysis patients. We hypothesized that the association between dialysis dose and mortality is attenuated with greater RKF.

Methods

Among 32 251 incident hemodialysis patients in a large US dialysis organization (2007-11), we examined the interaction between single-pool Kt/V (spKt/V) and renal urea clearance (rCLurea) levels in survival analyses using multivariable Cox proportional hazards regression model.

Results

The median rCLurea and mean baseline spKt/V were 3.06 [interquartile range (IQR) 1.74-4.85] mL/min/1.73 m2 and 1.32 ± 0.28, respectively. A total of 7444 (23%) patients died during the median follow-up of 1.2 years (IQR 0.5-2.2 years) with an incidence of 15.4 deaths per 100 patient-years. The Cox model with adjustment for case-mix and laboratory variables showed that rCLurea modified the association between spKt/V and mortality (Pinteraction = 0.03); lower spKt/V was associated with higher mortality among patients with low rCLurea (i.e. <3  mL/min/1.73 m2) but not among those with higher rCLurea. The adjusted mortality hazard ratios (aHRs) and 95% confidence intervals of the low (<1.2) versus high (≥1.2) spKt/V were 1.40 (1.12-1.74), 1.21 (1.10-1.33), 1.06 (0.98-1.14), and 1.00 (0.93-1.08) for patients with rCLurea of 0.0, 1.0, 3.0 and 6.0 mL/min/1.73 m2, respectively.

Conclusions

Incident hemodialysis patients with substantial RKF do not exhibit the expected better survival at higher hemodialysis doses. RKF levels should be taken into account when deciding on the dose of dialysis treatment among incident hemodialysis patients.

How to set the stage for a full-fledged clinical trial testing 'incremental haemodialysis'

Most people who make the transition to maintenance haemodialysis (HD) therapy are treated with a fixed dose of thrice-weekly HD (3HD/week) regimen without consideration of their residual kidney function (RKF). The RKF provides an effective and naturally continuous clearance of both small and middle molecules, plays a major role in metabolic homeostasis, nutritional status and cardiovascular health, and aids in fluid management. The RKF is associated with better patient survival and greater health-related quality of life. Its preservation is instrumental to the prescription of incremental (1HD/week to 2HD/week) HD. The recently heightened interest in incremental HD has been hindered by the current limitations of the urea kinetic model (UKM), which tend to overestimate the needed dialysis dose in the presence of a substantial RKF. A recent paper by Casino and Basile suggested a variable target model (VTM), which gives more clinical weight to the RKF and allows less frequent HD treatments at lower RKF as opposed to the fixed target model, based on the wrong concept of the clinical equivalence between renal and dialysis clearance. A randomized controlled trial (RCT) enrolling incident patients and comparing incremental HD (prescribed according to the VTM) with the standard 3HD/week schedule and focused on hard outcomes, such as survival and health-related quality of life of patients, is urgently needed. The first step in designing such a study is to compute the 'adequacy lines' and the associated fitting equations necessary for the most appropriate allocation of the patients in the two arms and their correct and safe follow-up. In conclusion, the potentially important clinical and financial implications of the incremental HD render it highly promising and warrant RCTs. The UKM is the keystone for conducting such studies.

Incremental hemodialysis, a valuable option for the frail elderly patient

Management of older people on dialysis requires focus on the wider aspects of aging as well as dialysis. Recognition and assessment of frailty is vital in changing our approach in elderly patients. Current guidelines in dialysis have a limited evidence base across all age group, but particularly the elderly. We need to focus on new priorities of care when we design guidelines "for people not diseases". Patient-centered goal-directed therapy, arising from shared decision-making between physician and patient, should allow adaption of the dialysis regime. Hemodialysis (HD) in the older age group can be complicated by intradialytic hypotension, prolonged time to recovery, and access-related problems. There is increasing evidence relating to the harm associated with the delivery of standard thrice-weekly HD. Incremental HD has a lower burden of treatment. There appears to be no adverse clinical effects during the first years of dialysis in presence of a significant residual kidney function. The advantages of incremental HD might be particularly important for elderly patients with short life expectancy. There is a need for more research into specific topics such as the assessment of the course of frailty with progression of chronic kidney disease and after dialysis initiation, the choice of dialysis modality impacting on the trajectory of frailty, the timing of dialysis initiation impacting on frailty or on other outcomes. In conclusion, understanding each individual's goals of care in the context of his or her life experience is particularly important in the elderly, when overall life expectancy is relatively short, and life experience or quality of life may be the priority.

Precision Medicine in the Transition to Dialysis and Personalized Renal Replacement Therapy

Launched in 2016, the overarching goal of the Precision Medicine Initiative is to promote a personalized approach to disease management that takes into account an individual's unique underlying biology and genetics, lifestyle, and environment, in lieu of a one-size-fits-all model. The concept of precision medicine is pervasive across many areas of nephrology and has been particularly relevant to the care of advanced chronic kidney disease patients transitioning to end-stage kidney disease (ESKD). Given many uncertainties surrounding the optimal transition of incident ESKD patients to dialysis and transplantation, as well as the high mortality rates observed during this delicate transition period, there is a pressing urgency for implementing precision medicine in the management of this population. Although the traditional paradigm has been to commence incident hemodialysis patients on a 3 times/week treatment regimen, largely driven by adequacy targets, there has been growing recognition that alternative treatment regimens (ie, incremental hemodialysis) may be preferred among certain subpopulations when taking into consideration factors such as patients' residual kidney function, volume status fluctuations, symptoms, and preferences. In this review, we examine the origins of current practices in how dialysis is initiated among incident ESKD patients; incremental dialysis therapy as a dynamic and patient-centric approach that is tailored to patients' unique characteristics; recent data on the incremental hemodialysis regimen and outcomes; and future research directions using a precision nephrology approach to ESKD management with the potential to develop novel approaches, tools, and collaborative efforts to improve the health, well-being, and survival of this population.

How can we advance in renal replacement therapy techniques?

End-Stage Renal Disease (ESRD) is one of the major causes of morbidity and mortality worldwide. Although the incidence of ESRD is relatively stable, the prevalence of maintenance dialysis is increasing, and it is expected to reach a staggering 5439 million patients worldwide by 2030. Despite the great technological evolution that has taken place in recent years, most patients are still treated with in-centre haemodialysis and their prognosis remains far from desirable. Since 1980, there has been an increasing interest in the development of a portable device for renal replacement therapy (RRT), which ultimately led to the creation of the Wearable Artificial Kidney (WAK) and the Wearable Ultrafiltration (WUF) system. Portable RRT devices may be acceptable alternatives that deal with several unmet clinical needs of ESRD patients. So far, 3 important human studies with WAK and WUF have been carried out and, although these devices require considerable technological improvement, their safety and efficacy in solute clearance and fluid removal is undeniable. In this article, we review the evolution of the WAK and the WUF and the main clinical trials performed, highlighting some of their technical features. Some of the main possible clinical advantages that could be achieved with these devices, as well as some economic aspects, are also pointed out. In the future, all renal replacement therapy techniques should evolve to perfectly match the clinical and personal needs of each patient, allowing for an improved health-related quality of life.

Hyponatremia in the Dialysis Population

Sodium derangements are among the most frequently encountered electrolyte disorders in patients with end-stage renal disease. As dialysis patients are predisposed to hyponatremia via multiple pathways, assessment of extracellular volume status is an essential first step in disentangling potential etiologic factors. In addition, multiple large population-based studies indicate that proxies of malnutrition (e.g., low body mass index, serum albumin, and serum creatinine levels) and loss of residual kidney function are important determinants of hyponatremia in dialysis patients. Among hemodialysis and peritoneal dialysis patients, evidence suggests that incrementally lower sodium levels are associated with increasingly higher death risk, highlighting the long-term risk of hyponatremia. Whereas in conventional survival models incrementally lower serum sodium concentrations are associated with worse mortality in hemodialysis patients, studies that have examined repeated measures of predialysis sodium have demonstrated mixed associations of time-varying sodium with higher mortality risk (i.e., U-shaped vs. inverse linear relationships). Although the causality of the hyponatremia-mortality association in dialysis patients remains uncertain, there are several plausible pathways by which lower sodium levels may lead to higher death risk, including central nervous system toxicity, falls and fractures, infection-related complications, and impaired cardiac function. Areas of uncertainty ripe for future studies include the following: (i) mechanistic pathways by which lower serum sodium levels are linked with higher mortality in dialysis patients, (ii) whether correction of sodium derangements improves outcomes, (iii) the optimal sodium target, and (iv) the impact of age and other sociodemographic factors on hyponatremia-outcome associations.

Once-weekly hemodialysis combined with low-protein and low-salt dietary treatment as a favorable therapeutic modality for selected patients with end-stage renal failure: a prospective observational study in Japanese patients

Background

For patients with end-stage renal failure (ESFR), thrice-weekly hemodialysis is a standard care. Once-weekly hemodialysis combined with low-protein and low-salt dietary treatment (OWHD-DT) have been rarely studied. Therefore, here, we describe our experience on OWHD-DT, and assess its long-term effectiveness.

Methods

We instituted OWHD-DT therapy in 112 highly motivated patients with creatinine clearance below 5.0 mL/min. They received once-weekly hemodialysis on a diet of 0.6 g/kg/day of protein adjusted for sufficient energy intake, and less than 6 g/day of salt intake. Serial changes in their clinical, biochemical and nutritional parameters were prospectively observed, and the weekly time spent for hospital visits as well as their monthly medical expenses were compared with 30 age, sex- and disease-matched thrice-weekly hemodialysis patients.

Results

The duration of successfully continued OWHD-DT therapy was more than 4 years in 11.6% of patients, 3 years in 16.1%, 2 years in 24.1% and 1 year in 51.8%. Time required per week for hospital attendance was 66.7% shorter and monthly medical expenses were 50.5% lower in the OWHD-DT group than in the thrice-weekly hemodialysis group (both p < 0.001). Patient survival rates in the OWHD-DT group were better than those in the Japan Registry (p < 0.001). Serum urea nitrogen significantly decreased; hemoglobin significantly increased; and albumin and body mass index were not significantly different from baseline values. In the OWHD-DT patients, serum albumin at 1 and 2 years after initiation of therapy was significantly higher compared with prevalent thrice-weekly hemodialysis patients. Furthermore, residual urine output was significantly higher in the OWHD-DT patients than in those receiving thrice-weekly hemodialysis (p < 0.05). Interdialytic weight gain over the course of the entire week between treatments in patients on OWHD-DT were 0.9 ± 1.0, 2.0 ± 1.3, 1.9 ± 1.2, 1.9 ± 1.5 and 1.8 ± 1.0 kg at 1, 6, 12, 18 and 24 months, respectively, though the weekly weight gain for thrice-weekly hemodialysis group (summed over all 3 treatments) was 8.6 ± 0.63 kg, p < 0.001.

Conclusions

OWHD-DT may be a favorable therapeutic modality for selected highly motivated patients with ESRF. However, this treatment cannot be seen as a general maintenance strategy.

Trial registration

UMIN000027555, May 30, 2017 (retrospectively registered).

Can twice weekly hemodialysis expand patient access under resource constraints?

The convention of prescribing hemodialysis on a thrice weekly schedule began empirically when it seemed that this frequency was convenient and likely to treat symptoms for a majority of patients. Later, when urea was identified as the main target and marker of clearance, studies supported the prevailing notion that thrice weekly dialysis provided appropriate clearance of urea. Today, national guidelines on hemodialysis from most countries recommend patients receive at least thrice weekly therapy. However, resource constraints in low- and middle-income countries (LMIC) have resulted in a substantial proportion of patients using less frequent hemodialysis in these settings. Observational studies of patients on twice weekly dialysis show that twice weekly therapy has noninferior survival rates compared with thrice weekly therapy. In fact, models of urea clearance also show that twice weekly therapy can meet urea clearance "targets" if patients have significant residual function or if they follow a protein-restricted diet, as may be common in LMIC. Greater reliance on twice weekly therapy, at least at the start of hemodialysis, therefore has potential to reduce health care costs and increase access to renal replacement therapy in low-resource settings; however, randomized control trials are needed to better understand long-term outcomes of twice versus thrice weekly therapy.

The variable target model: a paradigm shift in the incremental haemodialysis prescription

Background

The recent interest in incremental haemodialysis (HD) is hindered by the current prescription based on a fixed target model (FTM) for the total (dialytic + renal) equivalent continuous clearance (ECC). The latter is expressed either as standard Kt/V (stdKt/V), i.e. the pre-dialysis averaged concentration of urea-based ECC, or EKRc, i.e. the time averaged concentration-based ECC, corrected for volume (V) = 40 L. Accordingly, there are two different targets: stdKt/V = 2.3 volumes per week (v/wk) and EKRc = 13 mL/min/40 L. However, fixing the total ECC necessarily implies perfect equivalence of its components-the residual renal urea clearance (Kru) and dialysis clearance (Kd). This assumption is wrong because Kru has much greater clinical weight than Kd. Here we propose that the ECC target varies as an inverse function of Kru, from a maximum value in anuria to a minimum value at Kru levels not yet requiring dialysis. The aim of the present study was to compare the current FTM with the proposed variable target model (VTM).

Methods

The double pool urea kinetic model was used to model dialysis sessions for 360 virtual patients and establish equations predicting the ECC as a function of Kd, Kru and the number of sessions per week. An end-dialysis urea distribution V of 35 L (corresponding to a body surface area of 1.73 m 2 ) was used, so that the current EKRc target of 13 mL/min/40 L could be recalculated at an EKRc 35 value of 12 mL/min/35 L equal to 12 mL/min/1.73 m 2 . The latter also coincides with the maximum value of the EKRc 35 variable target in anuria. The minimum target value of EKRc 35 was assumed to coincide with Kru corrected for V = 35 L (i.e. Krc 35 = 6 mL/min/1.73 m 2 ). The corresponding target for stdKt/V was assumed to vary from 2.3 v/wk at Krc 35 = 0 to 1.7 v/wk at Krc 35 = 6 mL/min/1.73 m 2 . On this basis, the variable target values can be obtained from the following linear equations: target EKRc 35 = 12 - Krc 35 ; target stdKt/V = 2.3 - 0.1 × Krc 35 . Two versions of stdKt/V were considered: the classic version (stdKt/V Gotch ) with Kru at 70%, and the current version (stdKt/V Daug ) with Kru at 100%.

Results

The VTM with stdKt/V Gotch produces results very close to those using the FTM with stdKt/V Daug . Once-weekly HD is virtually not allowed by the FTM. In contrast, the VTM allows dialysis to start at Krc 35 ∼5 mL/min/1.73 m 2 on a once-weekly HD schedule, at least in relatively healthy patients; this schedule can be maintained until Krc 35 falls below 4 mL/min/1.73 m 2 , at which point the schedule should be changed to a twice-weekly HD schedule, that, in turn, could be maintained until Krc 35 falls below 2 mL/min/1.73 m 2 .

Conclusions

A paradigm shift from the FTM to the VTM in the prescription of incremental HD is proposed, whereby the VTM would allow less frequent treatments at lower Kru, with important clinical and economic implications. This approach is likely to be safe but needs to be confirmed by randomized controlled trials.

Feasibility of Incremental 2-Times Weekly Hemodialysis in Incident Patients With Residual Kidney Function

INTRODUCTION

We hypothesized that at least half of incident hemodialysis (HD) patients on 3-times weekly dialysis could safely start on an incremental, 2-times weekly HD schedule if residual kidney function (RKF) had been considered.

METHODS

RKF is assessed in all our HD patients. This single-center, retrospective cohort study of incident adult HD patients, who survived ≥6 months on a 3-times weekly HD regimen and had a timed urine collection within 3 months of starting HD, assessed each patient's theoretical ability to achieve adequate urea clearance, ultrafiltration rate, and hemodynamic stability if on 2-times weekly HD.

RESULTS

Of the 410 patients in the cohort, we found that 112 (27%) could have optimally and 107 (26%) could have been appropriately considered for 2-times weekly incremental HD. In general, diuretics were underutilized in >50% of subjects who had adequate RKF urea clearance. The optimal 2-times weekly patients had better potassium and phosphorus control. The correlation coefficient of calculated residual kidney urea clearance with 24-hour urine volume and with kinetic model residual kidney clearance was 0.68 and 0.99, respectively.

DISCUSSION

More than 50% of incident HD patients with RKF have adequate kidney urea clearance to be considered for 2-times weekly HD. When additionally ultrafiltration volume and blood pressure stability are taken into account, more than one-fourth of the total cohort could optimally start HD in an incremental fashion.

Renal Replacement Therapy and Incremental Hemodialysis for Veterans with Advanced Chronic Kidney Disease

Each year approximately 13,000 Veterans transition to maintenance dialysis, mostly in the traditional form of thrice-weekly hemodialysis from the start. Among >6000 dialysis units nationwide, there are currently approximately 70 Veterans Affairs (VA) dialysis centers. Given this number of VA dialysis centers and their limited capacity, only 10% of all incident dialysis Veterans initiate treatment in a VA center. Evidence suggests that, among Veterans, the receipt of care within the VA system is associated with favorable outcomes, potentially because of the enhanced access to healthcare resources. Data from the United States Renal Data System Special Study Center "Transition-of-Care-in-CKD" suggest that Veterans who receive dialysis in a VA unit exhibit greater survival compared with the non-VA centers. Substantial financial expenditures arise from the high volume of outsourced care and higher dialysis reimbursement paid by the VA than by Medicare to outsourced providers. Given the exceedingly high mortality and abrupt decline in residual kidney function (RKF) in the first dialysis year, it is possible that incremental transition to dialysis through an initial twice-weekly hemodialysis regimen might preserve RKF, prolong vascular access longevity, improve patients' quality of life, and be a more patient-centered approach, more consistent with "personalized" dialysis. Broad implementation of incremental dialysis might also result in more Veterans receiving care within a VA dialysis unit. Controlled trials are needed to examine the safety and efficacy of incremental hemodialysis in Veterans and other populations; the administrative and health care as well as provider structure within the VA system would facilitate the performance of such trials.

Twice-Weekly Hemodialysis in China: Can It Be A Better Option for Initiation or Maintenance Dialysis Therapy?

Cumulative evidence indicates it may be worthwhile revisiting the twice-weekly hemodialysis (HD) regimen as a valid option for individualized or incremental treatments for selected patients with end-stage renal disease. In this article, we will review the current evidences on the potential pros and cons of twice-weekly HD compared to thrice-weekly HD including China's experience in the practice of twice-weekly HD. A prudent patient selection and close dialysis adequacy monitoring might be necessary for this medical treatment choice. More randomized prospective controlled studies for the critical evaluation of twice-weekly dialysis are encouraged.

Is incremental hemodialysis ready to return on the scene? From empiricism to kinetic modelling

Most people who make the transition to maintenance dialysis therapy are treated with a fixed dose thrice-weekly hemodialysis regimen without considering their residual kidney function (RKF). The RKF provides effective and naturally continuous clearance of both small and middle molecules, plays a major role in metabolic homeostasis, nutritional status, and cardiovascular health, and aids in fluid management. The RKF is associated with better patient survival and greater health-related quality of life, although these effects may be confounded by patient comorbidities. Preservation of the RKF requires a careful approach, including regular monitoring, avoidance of nephrotoxins, gentle control of blood pressure to avoid intradialytic hypotension, and an individualized dialysis prescription including the consideration of incremental hemodialysis. There is currently no standardized method for applying incremental hemodialysis in practice. Infrequent (once- to twice-weekly) hemodialysis regimens are often used arbitrarily, without knowing which patients would benefit the most from them or how to escalate the dialysis dose as RKF declines over time. The recently heightened interest in incremental hemodialysis has been hindered by the current limitations of the urea kinetic models (UKM) which tend to overestimate the dialysis dose required in the presence of substantial RKF. This is due to an erroneous extrapolation of the equivalence between renal urea clearance (Kru) and dialyser urea clearance (Kd), correctly assumed by the UKM, to the clinical domain. In this context, each ml/min of Kd clears the urea from the blood just as 1 ml/min of Kru does. By no means should such kinetic equivalence imply that 1 ml/min of Kd is clinically equivalent to 1 ml/min of urea clearance provided by the native kidneys. A recent paper by Casino and Basile suggested a variable target model (VTM) as opposed to the fixed model, because the VTM gives more clinical weight to the RKF and allows less frequent hemodialysis treatments at lower RKF. The potentially important clinical and financial implications of incremental hemodialysis render it highly promising and warrant randomized controlled trials.

Nutritional Issues with Incremental Dialysis: The Role of Low-Protein Diets

A gentle start of dialysis is a welcome possibility for both patients and physicians. Incident dialysis patients often maintain residual kidney function (RKF) for a considerable period of time; the start of dialysis is often driven mainly by uremic symptoms. Recently, the combination of a low-protein diet, along with a less-frequent dialysis schedule, has regained interest as an alternative option in selected and motivated patients. In addition, there is renewed interest in a low-protein diet in patients with moderate to advanced chronic kidney disease (CKD). Dietary regimens have additional objectives now: obtaining better control of phosphate and potassium levels; preventing or reducing metabolic acidosis, protein catabolism, and malnutrition; and reducing uremic symptoms. In the eighties and early nineties, data from uncontrolled studies showed that combining a very low-protein diet with once weekly hemodialysis was a feasible approach. However, these diets were very demanding with poor patient compliance and had a high risk of smoldering malnutrition. However, recent experience has shown that the new protein-free foods have better palatability and nutritional properties; this has increased adherence to dietary prescriptions. Dietary regimens are now tailored to the patient's needs and habits. A multidisciplinary approach is considered crucial for updating medical needs and dietary prescriptions, ensuring adherence to the combined program, and avoiding the development of malnutrition and inadequate dialysis. Monitoring RKF is another key factor for the success of the program due to the importance of optimal timing of the transition to twice-weekly regimens and, eventually, thrice-weekly hemodialysis.

Incremental and infrequent hemodialysis: a new paradigm for both dialysis initiation and conservative management

Registry or national dialysis data show that a sizeable proportion of contemporary dialysis patients have substantial levels of residual kidney function especially upon transitioning to dialysis therapy. However, among incident hemodialysis patients, the prevailing paradigm has been to initiate "full-dose" triweekly treatment schedules irrespective of native kidney function in most developed countries. Recognizing the benefits of residual kidney function upon the health and survival of dialysis patients, there has been growing interest in incremental hemodialysis, in which dialysis frequency and dose are tailored according to the degree of patients' residual kidney function. Infrequent hemodialysis can also be used for those who prefer a more conservative approach in managing uremia. Clinical practice guidelines support the use of twice-weekly hemodialysis among patients with adequate residual kidney function (renal urea clearance >3 mL/min/1.73 m2), and a growing body of evidence indicates that incremental hemodialysis is associated with better preservation of residual kidney function without adversely impacting survival. Nonetheless, incremental hemodialysis remains an underutilized approach in this population. In this review, we will discuss the history of the twice- versus triweekly hemodialysis schedules; current clinical practice guidelines regarding infrequent hemodialysis; emerging data on incremental treatment regimens and outcomes; and guidelines for the practical implementation of incremental and infrequent hemodialysis in the clinical setting.

Dietary protein intake and chronic kidney disease

PURPOSE OF REVIEW

High-protein intake may lead to increased intraglomerular pressure and glomerular hyperfiltration. This can cause damage to glomerular structure leading to or aggravating chronic kidney disease (CKD). Hence, a low-protein diet (LPD) of 0.6-0.8 g/kg/day is often recommended for the management of CKD. We reviewed the effect of protein intake on incidence and progression of CKD and the role of LPD in the CKD management.

RECENT FINDINGS

Actual dietary protein consumption in CKD patients remains substantially higher than the recommendations for LPD. Notwithstanding the inconclusive results of the 'Modification of Diet in Renal Disease' (MDRD) study, the largest randomized controlled trial to examine protein restriction in CKD, several prior and subsequent studies and meta-analyses appear to support the role of LPD on retarding progression of CKD and delaying initiation of maintenance dialysis therapy. LPD can also be used to control metabolic derangements in CKD. Supplemented LPD with essential amino acids or their ketoanalogs may be used for incremental transition to dialysis especially on nondialysis days. The LPD management in lieu of dialysis therapy can reduce costs, enhance psychological adaptation, and preserve residual renal function upon transition to dialysis. Adherence and adequate protein and energy intake should be ensured to avoid protein-energy wasting.

SUMMARY

A balanced and individualized dietary approach based on LPD should be elaborated with periodic dietitian counseling and surveillance to optimize management of CKD, to assure adequate protein and energy intake, and to avoid or correct protein-energy wasting.

Treatment frequency and mortality among incident hemodialysis patients in the United States comparing incremental with standard and more frequent dialysis

Most patients with end-stage renal disease in the United States are initiated on thrice-weekly hemodialysis (HD) regimens. However, an incremental approach to HD may provide several patient benefits. We tested whether initiation of incremental HD does or does not compromise survival compared with a conventional HD regimen. The survival of 434 incremental, 50,162 conventional, and 160 frequent HD patients were compared using Cox regression analysis after matching for demographic and comorbid factors in a longitudinal national cohort of adult incident HD patients enrolled between January 2007 and December 2011. Sensitivity analysis included adjustment for residual kidney function. After adjustment for residual kidney function, all-cause mortality was not significantly different in the incremental compared with conventional HD group (hazard ratio 0.88, 95% confidence interval 0.72-1.08), but was higher in the frequent compared with the conventional HD group (hazard ratio, 1.56, 95% confidence interval 1.21-2.03). The comorbidity burden modified the association of treatment frequency and mortality, with higher comorbidity associated with higher mortality in the incremental HD group (hazard ratio, 1.77, 95% confidence interval 1.20-2.62) for a Charlson Comorbidity Index of ≥5. Thus, among incident HD patients with low or moderate comorbid disease, survival was similar for patients initiated on an incremental or conventional HD regimen. Clinical trials are needed to examine the safety and effectiveness of incremental HD and the selected patient populations who may benefit from an incremental approach to HDs initiation.

Incremental Hemodialysis, Residual Kidney Function, and Mortality Risk in Incident Dialysis Patients: A Cohort Study

BACKGROUND

Maintenance hemodialysis is typically prescribed thrice weekly irrespective of a patient's residual kidney function (RKF). We hypothesized that a less frequent schedule at hemodialysis therapy initiation is associated with greater preservation of RKF without compromising survival among patients with substantial RKF.

STUDY DESIGN

A longitudinal cohort.

SETTING & PARTICIPANTS

23,645 patients who initiated maintenance hemodialysis therapy in a large dialysis organization in the United States (January 2007 to December 2010), had available RKF data during the first 91 days (or quarter) of dialysis, and survived the first year.

PREDICTOR

Incremental (routine twice weekly for >6 continuous weeks during the first 91 days upon transition to dialysis) versus conventional (thrice weekly) hemodialysis regimens during the same time.

OUTCOMES

Changes in renal urea clearance and urine volume during 1 year after the first quarter and survival after the first year.

RESULTS

Among 23,645 included patients, 51% had substantial renal urea clearance (≥3.0mL/min/1.73m(2)) at baseline. Compared with 8,068 patients with conventional hemodialysis regimens matched based on baseline renal urea clearance, urine volume, age, sex, diabetes, and central venous catheter use, 351 patients with incremental regimens exhibited 16% (95% CI, 5%-28%) and 15% (95% CI, 2%-30%) more preserved renal urea clearance and urine volume at the second quarter, respectively, which persisted across the following quarters. Incremental regimens showed higher mortality risk in patients with inadequate baseline renal urea clearance (≤3.0mL/min/1.73m(2); HR, 1.61; 95% CI, 1.07-2.44), but not in those with higher baseline renal urea clearance (HR, 0.99; 95% CI, 0.76-1.28). Results were similar in a subgroup defined by baseline urine volume of 600mL/d.

LIMITATIONS

Potential selection bias and wide CIs.

CONCLUSIONS

Among incident hemodialysis patients with substantial RKF, incremental hemodialysis may be a safe treatment regimen and is associated with greater preservation of RKF, whereas higher mortality is observed after the first year of dialysis in those with the lowest RKF. Clinical trials are needed to examine the safety and effectiveness of twice-weekly hemodialysis.

Implications of the long interdialytic gap: a problem of excess accumulation vs. excess removal?

Evidence suggests that patients receiving intermittent maintenance hemodialysis treatments experience higher mortality the day after the long 2-day interdialytic gap. A new study confirms higher mortality and reports increased hospitalization immediately after the long interdialytic interval among incident hemodialysis patients in the United Kingdom. Larger fluid accumulation followed by excessive ultrafiltration and abrupt fluctuations in serum potassium concentrations may be among potential factors contributing to the morbidity and mortality of this precarious period.

Residual Kidney Function Decline and Mortality in Incident Hemodialysis Patients

In patients with ESRD, residual kidney function (RKF) contributes to achievement of adequate solute clearance. However, few studies have examined RKF in patients on hemodialysis. In a longitudinal cohort of 6538 patients who started maintenance hemodialysis over a 4-year period (January 2007 through December 2010) and had available renal urea clearance (CL_urea) data at baseline and 1 year after hemodialysis initiation, we examined the association of annual change in renal CL_urea rate with subsequent survival. The median (interquartile range) baseline value and mean±SD annual change of CL_urea were 3.3 (1.9-5.0) and -1.1±2.8 ml/min per 1.73 m², respectively. Greater CL_urea rate 1 year after hemodialysis initiation associated with better survival. Furthermore, we found a gradient association between loss of RKF and all-cause mortality: changes in CL_urea rate of -6.0 and +3.0 ml/min per 1.73 m² per year associated with case mix-adjusted hazard ratios (95% confidence intervals) of 2.00 (1.55 to 2.59) and 0. 61 (0.50 to 0.74), respectively (reference: -1.5 ml/min per 1.73 m² per year). These associations remained robust against adjustment for laboratory variables and ultrafiltration rate and were consistent across strata of baseline CL_urea, age, sex, race, diabetes status, presence of congestive heart failure, and hemoglobin, serum albumin, and serum phosphorus levels. Sensitivity analyses using urine volume as another index of RKF yielded consistent associations. In conclusion, RKF decline during the first year of dialysis has a graded association with all-cause mortality among incident hemodialysis patients. The clinical benefits of RKF preservation strategies on mortality should be determined.

Dietary Management of Incremental Transition to Dialysis Therapy: Once-Weekly Hemodialysis Combined With Low-Protein Diet

Initiation of thrice-weekly hemodialysis often results in a rapid loss of residual kidney function (RKF) including reduction in urine output. Preserving RKF longer is associated with better outcomes including greater survival in dialysis patients. An alternative approach aimed at preserving RKF is an incremental transition with less frequent hemodialysis sessions at the beginning with gradual increase in hemodialysis frequency over months. In addition to favorable clinical and economic implications, an incremental transition would also enhance a less stressful adaptation of the patient to dialysis therapy. The current guidelines provide only limited recommendations for incremental hemodialysis approach, whereas the potential role of nutritional management of newly transitioned hemodialysis patients is largely overlooked. We have reviewed previous reports and case studies of once-weekly hemodialysis treatment combined with low-protein, low-phosphorus, and normal-to-high-energy diet especially for nondialysis days, whereas on dialysis days, high protein can be provided. Such an adaptive dietary regimen may elicit more favorable outcomes including better preserved RKF, lower β2-microglobulin levels, improved phosphorus control, and lower doses of erythropoiesis-stimulating agents. Clinical and nutritional status and RKF should be closely monitored throughout the transition to once and then twice-weekly regimen and eventually thrice-weekly hemodialysis. Further studies are needed to verify the long-term safety and implications of this approach to dialysis transition.

Comparison of Clinical Outcome Between Twice-Weekly and Thrice-Weekly Hemodialysis in Patients With Residual Kidney Function

Residual kidney function (RKF) contributes to improved survival in hemodialysis (HD) patients. However, it is not clear whether RKF allows a comparable survival rate in patients undergoing twice-weekly HD compared with thrice-weekly HD.We enrolled 685 patients from a prospective multicenter observational cohort. RKF and HD adequacy was monitored regularly over 3-year follow-up. Patients with RKF were divided into groups undergoing twice-weekly HD (n = 113) or thrice-weekly HD (n = 137). Patients without RKF undergoing thrice-weekly HD (n = 435) were included as controls. Fluid balance and dialysis-associated characteristics were followed and clinical outcomes evaluated using all-cause mortality and cardiovascular events (CVE).In patients with RKF, baseline and follow-up RKF were significantly higher in patients undergoing twice-weekly HD than in those undergoing thrice-weekly HD. Total Kt/V urea (dialysis plus residual renal) in patients with RKF undergoing twice-weekly HD was greater than or equal to those in patients with or without RKF undergoing thrice-weekly HD. Compared with patients with RKF undergoing thrice-weekly HD, patients with RKF undergoing twice-weekly HD had no fluid excess, but their normalized protein catabolic rate became lower since 24-month follow up. In multivariable analyses, patients with RKF undergoing twice-weekly HD had a noninferior risk of mortality (hazard ratio [HR], 0.83; 95% confidence interval [95% CI], 0.34-2.01, P = 0.68) and of CVE (HR, 0.60; 95% CI, 0.28-1.29, P = 0.19) compared with patients without RKF undergoing thrice-weekly HD. However, this group showed an independent association with a greater risk of mortality compared with patients with RKF undergoing thrice-weekly HD (HR, 4.20; 95% CI, 1.02-17.32, P = 0.04).In conclusion, patients with RKF undergoing twice-weekly HD had an increased risk of mortality compared with those undergoing thrice-weekly HD. Decisions about twice-weekly HD should consider not only RKF, but also other risk factors such as normalized protein catabolic rate.

Timing of start of dialysis in diabetes mellitus patients: a systematic literature review

BACKGROUND

Diabetes mellitus is a frequent cause of the need for renal replacement therapy (RRT). Historically, RRT was started earlier in patients with diabetes, in an attempt to prevent complications of uraemia and diabetes. We did a systematic review to find support for this earlier start of dialysis in patients with versus without diabetes.

METHODS

The MEDLINE, EMBASE and CENTRAL databases were searched for articles about the timing of dialysis initiation in (subgroups of) patients with diabetes and CKD Stage 5.

RESULTS

A total of 340 papers were screened and 11 papers were selected to be reviewed. Only three studies showed data of at least one subgroup of patients with diabetes. Two observational studies concluded that start of dialysis with a higher estimated glomerular filtration rate (eGFR) is beneficial with regard to survival, one did not find a difference and six observational studies concluded that start of dialysis with a lower eGFR is associated with better survival in patients with diabetes. The effect of timing of initiation of dialysis did not differ between patients with versus without diabetes. Lastly, one randomized controlled trial (two papers) reported that there was no difference in survival between start at higher versus lower eGFR overall and a P-value for the interaction with diabetes of P = 0.63, indicating no difference between patients with versus without diabetes with regard to the timing of start of dialysis and subsequent mortality on dialysis.

CONCLUSIONS

There is no difference between early (eGFR) and late (lower eGFR) start of RRT with regard to mortality in patients with versus without diabetes. RRT should thus be initiated based on the same criteria in all patients, irrespective of the presence or absence of diabetes.

What Is Known and Unknown About Twice-Weekly Hemodialysis

BACKGROUND

The 2006 Kidney Disease Outcomes Quality Initiative guidelines suggest twice-weekly or incremental hemodialysis for patients with substantial residual kidney function (RKF). However, in most affluent nations de novo and abrupt transition to thrice-weekly hemodialysis is routinely prescribed for all dialysis-naïve patients regardless of their RKF. We review historical developments in hemodialysis therapy initiation and revisit twice-weekly hemodialysis as an individualized, incremental treatment especially upon first transitioning to hemodialysis therapy.

SUMMARY

In the 1960's, hemodialysis treatment was first offered as a life-sustaining treatment in the form of long sessions (≥10 hours) administered every 5 to 7 days. Twice- and then thrice-weekly treatment regimens were subsequently developed to prevent uremic symptoms on a long-term basis. The thrice-weekly regimen has since become the 'standard of care' despite a lack of comparative studies. Some clinical studies have shown benefits of high hemodialysis dose by more frequent or longer treatment times mainly among patients with limited or no RKF. Conversely, in selected patients with higher levels of RKF and particularly higher urine volume, incremental or twice-weekly hemodialysis may preserve RKF and vascular access longer without compromising clinical outcomes. Proposed criteria for twice-weekly hemodialysis include urine output >500 ml/day, limited interdialytic weight gain, smaller body size relative to RKF, and favorable nutritional status, quality of life, and comorbidity profile.

KEY MESSAGES

Incremental hemodialysis including twice-weekly regimens may be safe and cost-effective treatment regimens that provide better quality of life for incident dialysis patients who have substantial RKF. These proposed criteria may guide incremental hemodialysis frequency and warrant future randomized controlled trials.

Progressive Hemodialysis: Is It The Future?

Progressive hemodialysis is based on the simple idea of adjusting its dose according to residual renal function (RRF). The progressive, infrequent paradigm is slowly gaining a foothold among nephrologists, despite a lot of skepticism in the scientific world. Given the importance of RRF preservation in conservative therapy, it seems a contradiction to ignore the contribution of RRF when patients initiate hemodialysis (HD), especially when it is routinely considered with peritoneal dialysis. While a three-times-weekly HD regimen is broadly considered the standard starting regimen for new patients, twice-weekly HD has been used in selected patients and is currently a common practice in South-East Asia. Small studies indicate that a once-weekly HD regimen may be a viable starting option as well. Progressive hemodialysis still requires validation, yet it is promising. We share the belief that a randomized clinical trial to investigate progressive hemodialysis is much needed, but we also strongly recommend including a once-weekly HD starting dose as part of any such investigation.

Pro and con arguments in using alternative dialysis regimens in the frail and elderly patients

In the last decade, an increasing number of patients over 75 years of age are starting renal replacement therapy. Frailty is highly prevalent in elderly patients with end-stage renal disease (ESRD) in the context of the increased prevalence of some ESRD-associated conditions: protein-energy wasting, inflammation, anaemia, acidosis or hormonal disturbances. There are currently no hard data to support guidance on the optimal duration of dialysis for frail/elderly ESRD patients. The current debate is not about starting dialysis or managing conservatory frail ESRD patients, but whether a more intensive regimen once dialysis is initiated (for whatever reasons and circumstances) would improve patients' outcome. The most important issue is that all studies performed with extended/alternative dialysis regimens do not specifically address this particular type of patients and therefore all the inferences are derived from the general ESRD population. Care planning should be responsive to end-of-life needs whatever the treatment modality. Care in this setting should focus on symptom control and quality of life rather than life extension. We conclude that, similar to the general dialysed population, extensive application of more intensive dialysis schedules is not based on solid evidence. However, after a thorough clinical evaluation, a limited period of a trial of intensive dialysis could be prescribed in more problematic patients.

Dietary restrictions in dialysis patients: is there anything left to eat?

A significant number of dietary restrictions are imposed traditionally and uniformly on maintenance dialysis patients, whereas there is very little data to support their benefits. Recent studies indicate that dietary restrictions of phosphorus may lead to worse survival and poorer nutritional status. Restricting dietary potassium may deprive dialysis patients of heart-healthy diets and lead to intake of more atherogenic diets. There is little data about the survival benefits of dietary sodium restriction, and limiting fluid intake may inherently lead to lower protein and calorie consumption, when in fact dialysis patients often need higher protein intake to prevent and correct protein-energy wasting. Restricting dietary carbohydrates in diabetic dialysis patients may not be beneficial in those with burnt-out diabetes. Dietary fat including omega-3 fatty acids may be important caloric sources and should not be restricted. Data to justify other dietary restrictions related to calcium, vitamins, and trace elements are scarce and often contradictory. The restriction of eating during hemodialysis treatment is likely another incorrect practice that may worsen hemodialysis induced hypoglycemia and nutritional derangements. We suggest careful relaxation of most dietary restrictions and adoption of a more balanced and individualized approach, thereby easing some of these overzealous restrictions that have not been proven to offer major advantages to patients and their outcomes and which may in fact worsen patients' quality of life and satisfaction. This manuscript critically reviews the current paradigms and practices of recommended dietary regimens in dialysis patients including those related to dietary protein, carbohydrate, fat, phosphorus, potassium, sodium, and calcium, and discusses the feasibility and implications of adherence to ardent dietary restrictions and future research.