Association between high ultrafiltration rates and mortality in uraemic patients on regular haemodialysis. A 5-year prospective observational multicentre study

Hemodialysis Procedures for Stable Incident and Prevalent Patients Optimize Hemodynamic Stability, Dialysis Dose, Electrolytes, and Fluid Balance

The demographic profile of patients transitioning from chronic kidney disease to kidney replacement therapy is changing, with a higher prevalence of aging patients with multiple comorbidities such as diabetes mellitus and heart failure. Cardiovascular disease remains the leading cause of mortality in this population, exacerbated by the cardiovascular stress imposed by the HD procedure. The first year after transitioning to hemodialysis is associated with increased risks of hospitalization and mortality, particularly within the first 90-120 days, with greater vulnerability observed among the elderly. Based on data from clinics in Fresenius Medical Care Europe, Middle East, and Africa NephroCare, this review aims to optimize hemodialysis procedures to reduce mortality risk in stable incident and prevalent patients. It addresses critical aspects such as treatment duration, frequency, choice of dialysis membrane, dialysate composition, blood and dialysate flow rates, electrolyte composition, temperature control, target weight management, dialysis adequacy, and additional protocols, with a focus on mitigating prevalent intradialytic complications, particularly intradialytic hypotension prevention.

Do patients dialysing with higher ultrafiltration rates report more intradialytic symptoms and longer postdialysis recovery times?

BACKGROUND

Many hemodialysis (HD) patients report intradialytic symptoms, and take time to recover postdialysis. To improve quality of life, patient groups have highlighted the need to reduce postdialysis fatigue and other peridialytic symptoms. As compartmental shifts of fluid during dialysis have been proposed to cause peridialytic symptoms we investigated whether patients dialysing with higher ultrafiltration rates (UFR) reported more intradialytic symptoms and recovery times.

METHODS

We reviewed the hospital records of HD patients who completed a self-reported intradialytic symptom questionnaire, using a visual analogue scale, who had contemporaneous midweek pre- and postdialysis segmental bioimpedance measurements.

RESULTS

Six hundred and five patients returned the peridialytic symptom questionnaire with pre- and postdialysis bioimpedance measurements. The majority were male (64.8%), mean age 64.2 ± 15.6 years, duration of dialysis treatment 26.8 (10.7-59.2) months, 85% treated by hemodiafiltration and mean dialysate temperature 35.4 ± 0.4°C. We divided patients into terciles according to UFR adjusted for weight, and there was a greater fall in the ratio of extracellular water (ECW) to total body water (TBW) postdialysis in the nonfistula arm from the lower to middle to higher tercile (0.8 (0-1.54) vs. 1.28 (0.52-1.85) vs. 1.54 (0.78-2.52)), trunk (1.5 (0.74-2.27) vs. 1.53 (0.99-2.2) vs. 1.98 (1.18-2.66)), left leg (1.56 (0.49-2.25) vs. 1.77 (1.24-2.43) vs. 2.08 (1.18-2.95)), lower versus higher tercile p < 0.05. However, no differences in intradialytic symptoms or postdialysis recovery times between the UFR terciles were observed.

CONCLUSION

There were no differences in self-reported intradialytic symptoms or postdialysis recovery times with differing UFRs, despite changes in intracompartmental fluid shifts as measured by changes in ECW/TBW.

Heart failure with preserved ejection fraction in haemodialysis patients: prevalence, diagnosis, risk factors, prognosis

AIMS

Heart failure (HF) is a common complication and the leading cause of mortality in maintenance haemodialysis (MHD) patients. Few studies have investigated heart failure with preserved ejection fraction (HFpEF), which is known to affect a majority of patients. The objective of this study is to explore the prevalence, clinical profiles, diagnosis, risk factors and prognosis of MHD patients with HFpEF.

METHODS AND RESULTS

Four hundred thirty-nine patients haemodialyzsed for over 3 months were enrolled in the study and evaluated for HF according to the European Society of Cardiology guidelines. Clinical and laboratory parameters were recorded at baseline. The median follow-up of the study was 22.5 months. A total of 111 (25.3%) MHD patients were diagnosed with HF, while 94 (84.7%) of the HF patients were classified into HFpEF. The cut-off value of N-terminal pro-B-type natriuretic peptide (NT-proBNP) was 4922.5 pg/mL for predicting HFpEF (sensitivity 0.840, specificity 0.723, AUC 0.866) in MHD patients. Age, diabetes mellitus, coronary artery disease and serum phosphorus were independent risk factors for the incidence of HFpEF in MHD patients while normal urine volume, haemoglobin, serum iron and serum sodium were protective factors. MHD patients with HFpEF had a higher risk of all-cause mortality than those without HF (hazard ratio 2.47, 95% confidence interval 1.55-3.91, P < 0.0001).

CONCLUSIONS

The majority of MHD patients with HF were categorized into HFpEF, with a poor long-term survival rate. NT-proBNP beyond 4922.5 pg/mL performed well in the prediction of HFpEF in MHD patients.

Differences between Hepatic and Cerebral Regional Tissue Oxygen Saturation at the Onset of Intradialytic Hypotension

BACKGROUND

Intradialytic hypotension (IDH) is a critical pathological condition associated with all-cause mortality in patients undergoing hemodialysis (HD). However, few studies have investigated IDH-related changes in hepatic and cerebral regional tissue oxygen saturation (rSO2). This study investigated IDH-induced changes in hepatic and cerebral rSO2.

METHODS

Hepatic and cerebral rSO2 during HD were measured using an INVOS 5100C oxygen saturation monitor, and their percentage (%) changes during the development of IDH were analyzed. Ninety-one patients undergoing HD were investigated, including twenty with IDH.

RESULTS

In patients with IDH, % changes in hepatic and cerebral rSO2 decreased at the onset of IDH. Additionally, the % change in hepatic rSO2 was significantly larger than that in cerebral rSO2 (p < 0.001). In patients without IDH, no significant differences were found between the % changes in hepatic and cerebral rSO2 at the time of the lowest systolic blood pressure during HD. Multivariable linear regression analysis showed that the difference between the % changes in cerebral and hepatic rSO2 was significantly associated with the development of IDH (p < 0.001) and the ultrafiltration rate (p = 0.010).

CONCLUSIONS

Hepatic and cerebral rSO2 significantly decreased during the development of IDH, and hepatic rSO2 was more significantly decreased than cerebral rSO2 at the onset of IDH.

Bioimpedanciometry in nutritional and hydration assessments in a single dialysis center

BACKGROUND

Bioimpedance analysis (BIA) has been demonstrated to add accuracy to nutritional and volume status assessments in dialysis (HD) patients.

AIM

to describe a sample of dialysis patients from a single center on their demographics and BIA of volume distribution and nutritional status, and mortality during 12-month follow-up.

METHODS

prospective observational cohort study to evaluate vintage HD patients with single-frequency BIA.

RESULTS

we evaluated 82 patients, 29% over 65 years old. Elderly patients had higher ECW/TBW (0.51 vs. 0.44, p < 0.0001), and narrower phase angle (PhA) (4.9 vs. 6.4º, p < 0.0001). Fifteen patients (18.2%) died during follow-up, eight (53%) were elderly. Death was associated with age (62.6 vs. 50.2 years, p = 0.012), post-HD PhA (4.8 vs. 6.2º, p = 0.0001), and post-HD ECW/TBW (0.50 vs. 0.45, p = 0.015). The ROC curve analysis to predict mortality found ECW/TBW ≥ 0.47 and PhA ≤ 5.5º to have the best sensitivity and specificity. One-year patient survival was lower with post-HD ECW/TBW ≥ 0.47 (69.5% vs. 90.6%, p = 0.019), age ≥ 65 years (64.2%, vs. 86.2%, p = 0.029), and PhA ≤ 5.5º (68.2 vs. 91.0%, p = 0.002). Cox regression analysis demonstrated that PhA [HR 5.04 (95%CI 1.60-15.86), p = 0.006] remained associated with death after adjusting for age and ECW/TBW.

CONCLUSION

BIA is useful in assessing volume distribution and nutrition in HD patients, and combined with clinical judgement, may help determine dry weight, especially in elderly patients. Narrower PhA and higher ECW/TBW after HD were associated with poorer one-year survival.

Ultrafiltration Rate Levels in Hemodialysis Patients Associated with Weight-Specific Mortality Risks

BACKGROUND

We hypothesized that the association of ultrafiltration rate with mortality in hemodialysis patients was differentially affected by weight and sex and sought to derive a sex- and weight-indexed ultrafiltration rate measure that captures the differential effects of these parameters on the association of ultrafiltration rate with mortality.

METHODS

Data were analyzed from the US Fresenius Kidney Care (FKC) database for 1 year after patient entry into a FKC dialysis unit (baseline) and over 2 years of follow-up for patients receiving thrice-weekly in-center hemodialysis. To investigate the joint effect of baseline-year ultrafiltration rate and postdialysis weight on survival, we fit Cox proportional hazards models using bivariate tensor product spline functions and constructed contour plots of weight-specific mortality hazard ratios over the entire range of ultrafiltration rate values and postdialysis weights (W).

RESULTS

In the studied 396,358 patients, the average ultrafiltration rate in ml/h was related to postdialysis weight (W) in kg: 3W+330. Ultrafiltration rates associated with 20% or 40% higher weight-specific mortality risk were 3W+500 and 3W+630 ml/h, respectively, and were 70 ml/h higher in men than in women. Nineteen percent or 7.5% of patients exceeded ultrafiltration rates associated with a 20% or 40% higher mortality risk, respectively. Low ultrafiltration rates were associated with subsequent weight loss. Ultrafiltration rates associated with a given mortality risk were lower in high-body weight older patients and higher in patients on dialysis for more than 3 years.

CONCLUSIONS

Ultrafiltration rates associated with various levels of higher mortality risk depend on body weight, but not in a 1:1 ratio, and are different in men versus women, in high-body weight older patients, and in high-vintage patients.

Enhancing the Cardiovascular Safety of Hemodialysis Care Using Multimodal Provider Education and Patient Activation Interventions: Protocol for a Cluster Randomized Controlled Trial

BACKGROUND

End-stage kidney disease (ESKD) is treated with dialysis or kidney transplantation, with most patients with ESKD receiving in-center hemodialysis treatment. This life-saving treatment can result in cardiovascular and hemodynamic instability, with the most common form being low blood pressure during the dialysis treatment (intradialytic hypotension [IDH]). IDH is a complication of hemodialysis that can involve symptoms such as fatigue, nausea, cramping, and loss of consciousness. IDH increases risks of cardiovascular disease and ultimately hospitalizations and mortality. Provider-level and patient-level decisions influence the occurrence of IDH; thus, IDH may be preventable in routine hemodialysis care.

OBJECTIVE

This study aims to evaluate the independent and comparative effectiveness of 2 interventions-one directed at hemodialysis providers and another for patients-in reducing the rate of IDH at hemodialysis facilities. In addition, the study will assess the effects of interventions on secondary patient-centered clinical outcomes and examine factors associated with a successful implementation of the interventions.

METHODS

This study is a pragmatic, cluster randomized trial to be conducted in 20 hemodialysis facilities in the United States. Hemodialysis facilities will be randomized using a 2 × 2 factorial design, such that 5 sites will receive a multimodal provider education intervention, 5 sites will receive a patient activation intervention, 5 sites will receive both interventions, and 5 sites will receive none of the 2 interventions. The multimodal provider education intervention involved theory-informed team training and the use of a digital, tablet-based checklist to heighten attention to patient clinical factors associated with increased IDH risk. The patient activation intervention involves tablet-based, theory-informed patient education and peer mentoring. Patient outcomes will be monitored during a 12-week baseline period, followed by a 24-week intervention period and a 12-week postintervention follow-up period. The primary outcome of the study is the proportion of treatments with IDH, which will be aggregated at the facility level. Secondary outcomes include patient symptoms, fluid adherence, hemodialysis adherence, quality of life, hospitalizations, and mortality.

RESULTS

This study is funded by the Patient-Centered Outcomes Research Institute and approved by the University of Michigan Medical School's institutional review board. The study began enrolling patients in January 2023. Initial feasibility data will be available in May 2023. Data collection will conclude in November 2024.

CONCLUSIONS

The effects of provider and patient education on reducing the proportion of sessions with IDH and improving other patient-centered clinical outcomes will be evaluated, and the findings will be used to inform further improvements in patient care. Improving the stability of hemodialysis sessions is a critical concern for clinicians and patients with ESKD; the interventions targeted to providers and patients are predicted to lead to improvements in patient health and quality of life.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03171545; https://clinicaltrials.gov/ct2/show/NCT03171545.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/46187.

Why is Intradialytic Hypotension the Commonest Complication of Outpatient Dialysis Treatments?

Intradialytic hypotension (IDH) is the most frequent complication of hemodialysis (HD) treatments with a frequency of 10% to 12% for patients with chronic kidney disease attending for outpatient treatments and is associated with both temporary ischemic stress to vital organs, including the heart and brain, and increased patient mortality. Although there have been many different definitions of IDH over the years, an absolute nadir systolic blood pressure (SBP) has the strongest association with patient outcomes. The unifying pathophysiology is one of reduced effective blood volume, resulting in lower plasma tonicity, and if this cannot be adequately compensated for by activation of neurohumeral systems, then arteriolar tone and blood pressure fall. The risk factors for developing IDH are numerous, ranging from patient-related factors, including age and comorbidity with reduced cardiac reserve, to patient compliance with dietary and lifestyle advice, to reactions with the extracorporeal circuit and medications, choice of dialysate composition and temperature, setting of postdialysis target weight, ultrafiltration rate, and profiling. Advances in dialysis machine technology by providing real time estimates of the effective circulating volume and adjusting dialysate composition to maintain vascular tonicity are being developed, but currently require more sophisticated biofeedback loops to be clinically effective in preventing IDH. While awaiting advances in artificial intelligence, the clinician continues to rely on patient education to limit interdialytic weight gains, frequent assessment of the postdialysis target weight, adjusting dialysate composition and temperature, introducing convective therapies to increase thermal losses, and altering dialysis session duration and frequency to reduce ultrafiltration rate requirements.

Circumferential Strain as a Marker of Vessel Reactivity in Patients with Intradialytic Hypotension

Background and Objectives: Intradialytic hypotension (IDH) complicates 4 to 39.9% of hemodialysis (HD) sessions. Vessels' reactivity disturbances may be responsible for this complication. Two-dimensional speckle tracking is used to assess arterial circumferential strain (CS) as a marker of the effectiveness of the cardiovascular response to the reduction of circulating plasma. Materials and Methods: The common carotid artery (CCA) and common iliac artery (CIA) CSs were recorded using ultrasonography in 68 chronically dialyzed patients before and after one HD session. Results: In patients with IDH episodes (n = 26), the CCA-CS was significantly lower both before (6.28 ± 2.34 vs. 4.63 ± 1.74 p = 0.003) and after HD (5.00 (3.53-6.78) vs. 3.79 ± 1.47 p = 0.010) than it was in patients without this complication. No relationship was observed between CIA-CS and IDH. IDH patients had a significantly higher UF rate; however, they did not differ compared to complication-free patients either in anthropometric or laboratory parameters. Conclusions: Patients with IDH were characterized by lower pre- and post-HD circumferential strain of the common carotid artery. The lower CCA-CS showed that impaired vascular reactivity is one of the most important risk factors for this complication's occurrence.

High Ultrafiltration Rate Is Associated with Increased All-Cause Mortality in Incident Hemodialysis Patients with a High Cardiothoracic Ratio

A high ultrafiltration rate (UFR) is associated with increased mortality in hemodialysis patients. However, whether a high UFR itself or heart failure with fluid overload followed by a high UFR causes mortality remains unknown. In this study, 2615 incident hemodialysis patients were categorized according to their initial cardiothoracic ratios (CTRs) to assess whether UFR was associated with mortality in patients with high or low CTRs. In total, 1317 patients (50.4%) were women and 1261 (48.2%) were diabetic. During 2246 (1087−3596) days of follow-up, 1247 (47.7%) cases of all-cause mortality were noted. UFR quintiles 4 and 5 were associated with higher risks of all-cause mortality than UFR quintile 2 in fully adjusted Cox regression analysis. As the UFR increased by 1 mL/kg/h, the risk of all-cause mortality increased 1.6%. Subgroup analysis revealed that in UFR quintile 5, hazard ratios (HRs) for all-cause mortality were 1.91, 1.48, 1.22, and 1.10 for CTRs of >55%, 50−55%, 45−50%, and <45%, respectively. HRs for all-cause mortality were higher in women and patients with high body weight. Thus, high UFRs may be associated with increased all-cause mortality in incident hemodialysis patients with a high CTR, but not in those with a low CTR.

Bioimpedanciometria em avaliações nutricionais e de hidratação em um único centro de diálise

RESUMO Antecedentes: Análise de bioimpedância (BIA) demonstrou adicionar acurácia às avaliações de estado nutricional e de volume em pacientes em diálise (HD). Objetivo: descrever amostra de pacientes em diálise de um único centro quanto aos aspectos demográficos e BIA na distribuição de volume e no estado nutricional, e a mortalidade em 12 meses de acompanhamento. Métodos: estudo de coorte observacional prospectivo para avaliar pacientes prevalentes em HD com BIA de frequência única. Resultados: avaliamos 82 pacientes, 29% acima de 65 anos. Pacientes idosos apresentaram maior AEC/ACT (0,51 vs. 0,44; p < 0,0001), e ângulo de fase mais estreito (PhA) (4,9 vs. 6,4º; p < 0,0001). Quinze pacientes (18,2%) foram a óbito durante acompanhamento, oito (53%) eram idosos. Óbito foi associado à idade (62,6 vs. 50,2 anos, p = 0,012), PhA pós-HD (4,8 vs. 6,2º; p = 0,0001), e AEC/ACT pós-HD (0,50 vs. 0,45, p = 0,015). A análise da curva ROC para prever mortalidade constatou que AEC/ACT ≥ 0,47 e PhA ≤ 5,5º apresentam melhor sensibilidade e especificidade. Sobrevida do paciente em um ano foi menor com AEC/ACT pós-HD ≥ 0,47 (69,5% vs. 90,6%; p = 0,019), idade ≥ 65 anos (64,2% vs. 86,2%; p = 0,029), e PhA ≤ 5,5º (68,2 vs. 91,0%; p = 0,002). A análise de regressão de Cox demonstrou que PhA [HR 5,04 (IC 95% 1,60–15,86); p = 0,006] permaneceu associado ao óbito após ajuste para idade e AEC/ACT. Conclusão: BIA é útil ao avaliar distribuição de volume e nutrição em pacientes em HD, e juntamente com julgamento clínico, pode ajudar a determinar o peso seco, principalmente em pacientes idosos. PhA mais estreito e maior AEC/ACT pós-HD foram associados a pior sobrevida em um ano.

Association of Bradycardia and Asystole Episodes with Dialytic Parameters: An Analysis of the Monitoring in Dialysis (MiD) Study

Background

Bradycardia and asystole events are common among patients treated with maintenance hemodialysis. However, triggers of these events in patients on maintenance hemodialysis (HD), particularly during the long interdialytic period when these events cluster, are uncertain.

Methods

The Monitoring in Dialysis Study (MiD) enrolled 66 patients on maintenance HD who were implanted with loop recorders and followed for 6 months. We analyzed associations of predialysis laboratory values with clinically significant bradyarrhythmia or asystole (CSBA) during the 12 hours before an HD session. Associations with CSBA were analyzed with mixed-effect models. Adjusted negative binomial mixed-effect regression was used to estimate incidence rate ratios (IRR) for CSBA. We additionally evaluated associations of CSBA at any time during follow-up with time-averaged dialytic and laboratory parameters and associations of peridialytic parameters with occurrence of CSBA from the start of one HD session to the beginning of the next.

Results

There were 551 CSBA that occurred in the last 12 hours of the interdialytic interval preceding 100 HD sessions in 12% of patients and 1475 CSBA events in 23% of patients overall. We did not identify significant associations between dialytic parameters or serum electrolytes and CSBA in the last 12 hours of the interdialytic interval in adjusted analyses. Median time-averaged ultrafiltration rate was significantly higher in individuals without CSBA (9.8 versus 8, P=0.04). Use of dialysate sodium concentrations ≤135 (versus 140) mEq/L was associated with a reduced risk of CSBA from the start of one session to the beginning of next.

Conclusions

Although a few factors had modest associations with CSBA in some analyses, we did not identify any robust associations of modifiable parameters with CSBA in the MiD Study. Further investigation is needed to understand the high rates of arrhythmia in the hemodialysis population.

Low dialysate sodium in children and young adults on maintenance hemodialysis: a prospective, randomized, crossover study

BACKGROUND

The optimal dialysate sodium concentration (dNa) in children on hemodialysis (HD) is unknown. The aim of this study was to compare the effect on interdialytic weight gain (IDWG) and blood pressure (BP) of a low (135 mmol/l) and standard dNa (138 mmol/l) in children and young adults on maintenance HD.

METHODS

This prospective single-blind randomized crossover study consisted of a randomized sequence of two phases: "standard dNa" of 138 mmol/L and "low dNa" of 135 mmol/L. Each phase lasted 4 weeks. Inclusion criteria were age < 25 years, hypertension, pre-HD serum Na (sNa) ≥ 130 mmol/L, and occurrence of symptoms in less than 25% of sessions. Primary outcomes were pre-HD systolic and diastolic BP and IDWG.

RESULTS

Fifteen patients were recruited, mean age 17.8 ± 4.4 years. Pre-HD SBP and DBP were not different between the two treatments. Mean IDWG was significantly lower with low dNa than with standard dNa: 2.12 ± 1.39% vs. 2.77 ± 1.53%, respectively (p = 0.008). The first-hour refill index (a volume index based on blood-volume monitoring) was significantly lower with dNa 135 mmol/L (p = 0.018). The mean Na gradient (dNa-sNa) was - 2.53 ± 2.4 mmol/L with dNa 135 mmol/L and 0.17 ± 2.8 mmol/L with dNa 138 mmol/L (p = 0.0001). The incidence of symptomatic sessions was similar (1.0% vs. 1.0%).

CONCLUSIONS

In a selected population of hypertensive pediatric and young adult HD patients, a dNa of 135 mmol/L was associated with a significant reduction of IDWG compared with a dNa of 138 mmol/L. Furthermore, long-term studies are needed to investigate the effect of lowering dNa on BP. A higher resolution version of the Graphical abstract is available as Supplementary information.

Palliative care needs and symptom burden in younger and older patients with end-stage renal disease undergoing maintenance hemodialysis: A cross-sectional study

Objectives

To investigate the current situation of palliative care needs and the symptom burden in patients with end-stage renal disease (ESRD) undergoing maintenance hemodialysis (MHD), and to explore whether there are differences between younger and older patients.

Methods

This cross-sectional study was conducted in the hemodialysis centers of two tertiary hospitals from November 2021 to June 2022. Participants were selected by convenience sampling. Socio-demographics, clinical characteristics, the Palliative Care Outcome Scale (POS), the Dialysis Symptom Index (DSI), and health-related quality of life (EQ-5D-3L) were used for evaluation. Descriptive statistics, between-group comparisons, and correlation analysis were used to analyze the data.

Results

A total of 236 patients were enrolled, including 118 younger and 118 older patients. The total median (P 25, P 75) POS score was 16.0 (12.0, 23.0), and the score was higher in older patients (P < 0.01). The mean total number of symptoms in MHD patients was 15.04 ± 5.06, and the overall median symptom severity score was 59.0 (52.0, 71.0); these scores were higher in the older group (P < 0.01). The most common symptom was dry mouth (91.5%), followed by itching (83.1%), and dry skin (82.2%). Additionally, palliative care needs were significantly associated with symptom burden and health-related quality of life (HRQOL).

Conclusions

The results showed that patients with ESRD undergoing MHD have a significant symptom burden and moderate palliative care needs, which are more severe in older patients. Therefore, interdisciplinary teams should be formed to actively manage patients' symptoms and meet the physical, psychological, social, and spiritual needs related to palliative care to improve patients' HRQOL.

A first proof-of-concept for the non-invasive, time-efficient measurement of the plasma sodium concentration for individualized dialysis

Dialysis-induced changes in plasma sodium concentration may cause undesirable side effects. To prevent these, the sodium content in dialysis fluid has to be individualized based on the patient's plasma sodium concentration. In this paper, we describe a simple conductivity based method for measuring the plasma sodium concentration. The method is based on performing a bypass during which the residual volume on the dialysate side of the dialyzer at least partially adopts the sodium concentration on the blood side. The conductivity at dialysate outlet of the dialyzer after the end of bypass corresponds to the sodium concentration. We show that already 14 s of bypass are sufficient to subsequently measure a conductivity that correlates with the blood-side sodium concentration. Thus, the short bypass method allows a time saving of 88% compared to the long bypass of 120 s. In vitro experiments with bovine blood show that plasma sodium concentration can be non-invasively and time-efficiently measured during dialysis. Bland Altman analysis reveals a bias of 0.28 mmol/l and limits of agreement of -3.17 and 3.74 mmol/l for the long bypass. For the short bypass, bias is 0.09 mmol/l and limits are -3.90 and 4.08 mmol/l. Since the method presented is based on established conductivity cells, no additional sensors are required, so that the method could be easily implemented in dialysis machines. In future, performing a bypass at the beginning of a treatment may be used to adjust the composition of dialysis fluid individually for each patient.

Proportion of Hemodialysis Treatments with High Ultrafiltration Rate and the Association with Mortality

Background

Rapid fluid removal during hemodialysis has been associated with increased mortality. The limit of ultrafiltration rate (UFR) monitored by the Centers for Medicare & Medicaid Services is 13 ml/kg per hour. It is not clear if the proportion of treatments with high UFR is associated with higher mortality. We examined the association of proportion of dialysis treatments with high UFR and mortality in end stage kidney failure patients receiving hemodialysis.

Methods

This was a retrospective study of incident patients initiating hemodialysis between January 1, 2010, and December 31, 2019, at Emory dialysis centers. The proportion of treatments with high UFR (>13 ml/kg per hour) per patient was calculated using data from the initial 3 months of dialysis therapy. Patients were categorized on the basis of quartiles of proportion of dialysis sessions with high UFR. Risk of death and survival probabilities were calculated and compared for all quartiles.

Results

Of 1050 patients eligible, the median age was 59 years, 56% were men, and 91% were Black. The median UFR was 6.5 ml/kg per hour, and the proportion of sessions with high UFR was 5%. Thirty-one percent of patients never experienced high UFR. Being a man, younger age, shorter duration of hemodialysis sessions, lower weight, diabetic status, higher albumin, and history of heart failure were associated with a higher proportion of sessions with high UFR. Patients in the higher quartile (26% dialysis with high UFR, average UFR 9.8 ml/kg per hour, median survival of 5.6 years) had a higher risk of death (adjusted hazard ratio 1.54; 95% CI, 1.13 to 2.10) compared with those in the lower quartile (0% dialysis with high UFR, average UFR 4.7 ml/kg per hour, median survival 8.8 years).

Conclusions

Patients on hemodialysis who did not experience frequent episodes of elevated UFR during the first 3 months of their dialysis tenure had a significantly lower risk of death compared with patients with frequent episodes of high UFR.

Ultrafiltration rate thresholds associated with increased mortality risk in hemodialysis, unscaled or scaled to body size

Introduction

One proposed threshold ultrafiltration rate (UFR) of concern in hemodialysis patients is 13 ml/h per kg. We evaluated associations among UFR, postdialysis weight, and mortality to determine whether exceeding such a threshold would result in similar levels of risk for patients of different body weights.

Methods

Data were analyzed in this retrospective cohort study for 1 year following dialysis initiation (baseline) and over 2 years of follow-up in incident patients receiving thrice-weekly in-center hemodialysis. Patient-level UFR was averaged over the baseline period. To investigate the joint effect of UFR and postdialysis weight on survival, we fit Cox proportional hazards models using bivariate tensor product spline functions, adjusting for sex, race, age, diabetes, and predialysis serum albumin, phosphorus, and systolic blood pressure (BP). We constructed contour plots of mortality hazard ratios (MHRs) over the entire range of UFR values and postdialysis weights.

Results

In the studied 2542 patients, UFR not scaled to body weight was strongly associated with MHR, whereas postdialysis weight was inversely associated with MHR. MHR crossed 1.5 when unscaled UFR exceeded 1000 ml/h, and this relationship was largely independent of postdialysis weight in the range of 80 to 140 kg. A UFR warning level associated with a lower MHR of 1.3 would be 900 ml/h, whereas the UFR associated with an MHR of 1.0 was patient-size dependent. The MHR when exceeding a UFR threshold of 13 ml/h per kg was dependent on patient weight (MHR = 1.20, 1.45, and >2.0 for a 60, 80, and 100 kg patient, respectively).

Conclusion

UFR thresholds based on unscaled UFR give more uniform risk levels for patients of different sizes than thresholds based on UFR/kg.

Management of hypertension and renin-angiotensin-aldosterone system blockade in adults with diabetic kidney disease: Association of British Clinical Diabetologists and the Renal Association UK guideline update 2021

People with type 1 and type 2 diabetes are at risk of developing progressive chronic kidney disease (CKD) and end-stage kidney failure. Hypertension is a major, reversible risk factor in people with diabetes for development of albuminuria, impaired kidney function, end-stage kidney disease and cardiovascular disease. Blood pressure control has been shown to be beneficial in people with diabetes in slowing progression of kidney disease and reducing cardiovascular events. However, randomised controlled trial evidence differs in type 1 and type 2 diabetes and different stages of CKD in terms of target blood pressure. Activation of the renin-angiotensin-aldosterone system (RAAS) is an important mechanism for the development and progression of CKD and cardiovascular disease. Randomised trials demonstrate that RAAS blockade is effective in preventing/ slowing progression of CKD and reducing cardiovascular events in people with type 1 and type 2 diabetes, albeit differently according to the stage of CKD. Emerging therapy with sodium glucose cotransporter-2 (SGLT-2) inhibitors, non-steroidal selective mineralocorticoid antagonists and endothelin-A receptor antagonists have been shown in randomised trials to lower blood pressure and further reduce the risk of progression of CKD and cardiovascular disease in people with type 2 diabetes. This guideline reviews the current evidence and makes recommendations about blood pressure control and the use of RAAS-blocking agents in different stages of CKD in people with both type 1 and type 2 diabetes.

Ultrafiltration rate and incident atrial fibrillation among older individuals initiating hemodialysis

BACKGROUND

Higher ultrafiltration (UF) rates are associated with numerous adverse cardiovascular outcomes among individuals receiving maintenance hemodialysis. We undertook this study to investigate the association of UF rate and incident atrial fibrillation in a large, nationally representative US cohort of incident, older hemodialysis patients.

METHODS

We used the US Renal Data System linked to the records of a large dialysis provider to identify individuals ≥67 years of age initiating hemodialysis between January 2006 and December 2011. We applied an extended Cox model as a function of a time-varying exposure to compute adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the association of delivered UF rate and incident atrial fibrillation.

RESULTS

Among the 15 414 individuals included in the study, 3177 developed atrial fibrillation. In fully adjusted models, a UF rate >13 mL/h/kg (versus ≤13 mL/h/kg) was associated with a higher hazard of incident atrial fibrillation [adjusted HR 1.19 (95% CI 1.07-1.30)]. Analyses using lower UF rate thresholds (≤10 versus >10 mL/h/kg and ≤8 versus >8 mL/h/kg, separately) yielded similar results. Analyses specifying the UF rate as a cubic spline (per 1 mL/h/kg) confirmed an approximately linear dose-response relationship between the UF rate and the risk of incident atrial fibrillation: risk began at UF rates of ~6 mL/h/kg and the magnitude of this risk flattened, but remained elevated, at rates ≥9 mL/h/kg.

CONCLUSION

In this observational study of older individuals initiating hemodialysis, higher UF rates were associated with higher incidences of atrial fibrillation.

Changes in practice patterns in Japan from before to after JSDT 2013 guidelines on hemodialysis prescriptions: results from the JDOPPS

BACKGROUND

The Japanese Society for Dialysis Therapy (JSDT) published in 2013 inaugural hemodialysis (HD) guidelines. Specific targets include 1.4 for single-pool Kt/V (spKt/V) with a minimum dose of 1.2, minimum dialysis session length of 4 hours, minimum blood flow rate (BFR) of 200 mL/min, fluid removal rate no more than 15 mL/kg/hr, and hemodiafiltration (HDF) therapy for certain identified symptoms. We evaluated the effect of these guidelines on actual practice in the years spanning 2005 - 2018.

METHODS

Analyses were carried out to describe trends in the above HD prescription practices from December 2005 to April 2013 (before guideline publication) to August 2018 based on prevalent patient cross-sections from approximately 60 randomly selected HD facilities participating in the Japan Dialysis Outcomes and Practice Patterns Study.

RESULTS

From April 2006 to August 2017 continual rises occurred in mean spKt/V (from 1.35 to 1.49), and percent of patients having spKt/V>1.2 (71% to 85%). Mean BFR increased with time from 198.3 mL/min (April 2006) to 218.4 mL/min (August 2017) , along with percent of patients with BFR >200 ml/min (65% to 85%). HDF use increased slightly from 6% (April 2006 and August 2009) to 8% by April 2013, but increased greatly thereafter to 23% by August 2017. In contrast, mean HD treatment time showed little change from 2006-2017, whereas mean UFR declined from 11.3 in 2006 to 8.4 mL/Kg/hour in 2017.

CONCLUSIONS

From 2006 - 2018 Japanese HD patients experienced marked improvement in reaching the spKt/V target specified by the 2013 JSDT guidelines. This may have been due to moderate increase in mean BFR even though mean HD session length did not change much. In addition, HDF use increased dramatically in this time period. Other HD delivery changes during this time, such as increased use of super high flux dialyzers, also merit study. While we cannot definitively conclude a causal relationship between the publication of the guidelines and the subsequent practice changes in Japan, those changes moved practice closer to the recommendations of the guidelines.

Managing heart failure in dialysis patients

The heart and the kidney are intimately connected. They communicate in a bidirectional manner through a variety of pathways, forming an interdependent relationship. Recognition of this co-dependency is crucial in managing patients with cardiorenal syndrome, as we begin to realise the inevitability of disease progression to both organs; and an approach that focuses treatment on one organ may result in worsening outcome on the other organ. When faced with patients with deteriorating cardiac disease, nephrologists tend to focus on stabilisation of cardiac function and accept the heart disease to be unmodifiable. Likewise, cardiac patients with persistent kidney failure are presented with a poor renal prognosis and prepared for kidney transplantation. Adopting a cardio-protective approach in combination with dialysis optimisation raises hope for a more positive outcome with evidence of cardiac and renal recovery in some patients.

Association between Net Ultrafiltration Rate and Renal Recovery among Critically Ill Adults with Acute Kidney Injury Receiving Continuous Renal Replacement Therapy: An Observational Cohort Study

INTRODUCTION

Higher net ultrafiltration (UFNET) rates are associated with mortality among critically ill patients with acute kidney injury (AKI) and treated with continuous renal replacement therapy (CRRT).

OBJECTIVE

The aim of the study was to discover whether UFNET rates are associated with renal recovery and independence from renal replacement therapy (RRT).

METHODS

Retrospective cohort study using data from the Randomized Evaluation of Normal versus Augmented Level of Renal Replacement Therapy trial that enrolled 1,433 critically ill patients with AKI and treated with CRRT between December 2005 and November 2008 across 35 intensive care units in Australia and New Zealand. We examined the association between UFNET rate and time to independence from RRT by day 90 using competing risk regression after accounting for mortality. The UFNET rate was defined as the volume of fluid removed per hour adjusted for patient body weight.

RESULTS AND CONCLUSIONS

Median age was 67.3 (interquartile range [IQR], 57-76.3) years, 64.4% were male, median Acute Physiology and Chronic Health Evaluation-III score was 100 (IQR, 84-118), and 634 (44.2%) died by day 90. Kidney recovery occurred in 755 patients (52.7%). Using tertiles of UFNET rates, 3 groups were defined: high, >1.75; middle, 1.01-1.75; and low, <1.01 mL/kg/h. Proportion of patients alive and independent of RRT among the groups were 47.8 versus 57.2 versus 53.0%; p = 0.01. Using competing risk regression, higher UFNET rate tertile compared with middle (cause-specific hazard ratio [csHR], 0.79, 95% CI, 0.66-0.95; subdistribution hazard ratio [sHR], 0.80, 95% CI, 0.67-0.97) and lower (csHR, 0.69, 95% CI, 0.56-0.85; sHR, 0.78, 95% CI 0.64-0.95) tertiles were associated with a longer time to independence from RRT. Every 1.0 mL/kg/h increase in rate was associated with a lower probability of kidney recovery (csHR, 0.81, 95% CI, 0.74-0.89; and sHR, 0.87, 95% CI, 0.80-0.95). Using the joint model, longitudinal increases in UFNET rates were also associated with a lower renal recovery (β = -0.29, p < 0.001). UFNET rates >1.75 mL/kg/h compared with rates 1.01-1.75 and <1.01 mL/kg/h were associated with a longer duration of dependence on RRT. Randomized clinical trials are required to confirm this UFNET rate-outcome relationship.

Effect of intestinal dialysis using polyethylene glycol on fluid balance and thirst in maintenance hemodialysis patients: A comparative study

High inter-dialytic weight gains (IDWG) and Hyperkalemia have been associated with adverse outcomes like poor quality of life and high mortality. Thirst remains an unsolved problem in hemodialysis (HD) patients. The aim of this study was to evaluate the effect of polyethylene glycol (PEG) based intestinal dialysis on IDWG, thirst and biochemical parameters. A prospective interventional evidenced based paired comparative single center study was conducted. Thirty-five anuric patients on weekly thrice HD were studied for four consecutive dialysis weeks. Before the mid-week dialysis day of week 3, Patients received 2 L PEG solution. The primary end points were change in mean relative IDWG and change in mean subjective thirst feeling as measured on visual analog scale (VAS) with secondary endpoints being change in small molecule clearance. There was significant reduction in IDWG after the therapy from 3 ± 0.81 L to 2.35 ± 0.72 (P = 0.002). The therapy also reduced the % IDWG BW from 5.1 ± 1.7% to 4.15 ± 1.6% (P = 0.017). No change in thirst was seen, that is, 6.16 ± 0.66, 6.14 ± 0.64, and 6.16 ± 0.65 (P = 0.986). A multivariate linear regression did not reveal any effect of age, gender, and co-morbidities on the reduction of IDWG and thirst. The therapy achieved a significant urea, creatinine, and potassium reduction of 8.23%, 8.13%, and 8.33% respectively with an increase in sodium levels by 0.86%. This modality reduced the IDWG, was found to be a potent treatment modality for hyperkalemia but did not affect thirst sensation even after consumption of 2 L solution.

Ultrafiltration rate adjusted to body weight and mortality in hemodialysis patients

BACKGROUND AND AIMS

Mortality among hemodialysis patients remains high. An elevated ultrafiltration rate adjusted by weight (UFR/W) has been associated with hypotension and higher risk of death and/or cardiovascular events.

METHODS

We evaluated the association between UFR/W and mortality in 215 hemodialysis patients. The mean follow-up was 28 ± 6.12 months. We collected patients' baseline characteristics and mean UFR/W throughout the follow-up.

RESULTS

Mean UFR/W was 9.0 ± 2,4 and tertiles 7.1 y 10.1 mL/kg/h. We divided our population according to the percentage of sessions with UFR/W above the limits described in the literature associated with increased mortality (10.0 ml/kg/h and 13.0 mL/kg/h). Patients with higher UFR/W were younger, with higher interdialytic weight gain and weight reduction percentage but lower dry, pre and post dialysis weight. Throughout the follow-up, 46 (21.4%) patients died, the majority over 70 years old, diabetic or with cardiovascular disease. There were neither differences regarding mortality between groups nor differences in UFR/W among patients who died and those who did not. Contrary to previous studies, we did not find an association between UFR/W and mortality, maybe due to a higher prevalence in the use of cardiovascular protection drugs and lower UFR/W.

CONCLUSIONS

The highest UFR/W were observed in younger patients with lower weight and were not associated with an increased mortality.

Predictors of kidney function recovery among incident ESRD patients

Background

ESRD is considered an irreversible loss of renal function, yet some patients will recover kidney function sufficiently to come off dialysis. Potentially modifiable predictors of kidney recovery, such as dialysis prescription, have not been fully examined.

Methods

Retrospective cohort study using United States Renal Data System (USRDS) data to identify incident hemodialysis (HD) patients between 2012 and 2016, the first 4 years for which dialysis treatment data is available. The primary outcome was kidney recovery within 1 year of ESRD and HD initiation, defined by a specific recovery code and survival off dialysis for at least 30 days. Patient and treatment characteristics were compared between those that recovered versus those that remained dialysis-dependent. A time-dependent survival model was used to identify independent predictors of kidney recovery.

Results

During the study period, there were 372,387 incident HD patients with available data, among whom 16,930 (4.5%) recovered to dialysis-independence. Compared to non-recovery, a higher proportion of patients with kidney recovery were of white race, and non-Hispanic ethnicity. Both groups had a similar age distribution. Patients with an acute kidney injury diagnosis as primary cause of ESRD were most likely to recover, but the most common ESRD diagnosis among recovering patients was type 2 diabetes (29.8% of recovery cases). Higher eGFR and lower albumin at ESRD initiation were associated with increased likelihood of recovery. When examining HD ultrafiltration rate (UFR), each quintile above the first quintile was associated with a progressively lower likelihood of recovery (HR 0.45, 95% CI 0.43–0.48 for highest versus lowest quintile, p < 0.001).

Conclusions

We identified non-modifiable and potentially modifiable factors associated with kidney recovery which may assist clinicians in counseling and monitoring incident ESRD patients with a greater chance to gain dialysis-independence. Clinical trials are warranted to examine the impact of dialysis prescription on subsequent kidney function recovery.

Ultrafiltration in critically ill patients treated with kidney replacement therapy

Management of fluid overload is one of the most challenging problems in the care of critically ill patients with oliguric acute kidney injury. Various clinical practice guidelines support fluid removal using ultrafiltration during kidney replacement therapy. However, ultrafiltration is associated with considerable risks. Emerging evidence from observational studies suggests that both slow and fast rates of net fluid removal (that is, net ultrafiltration (UFNET)) during continuous kidney replacement therapy are associated with increased mortality compared with moderate UFNET rates. In addition, fast UFNET rates are associated with an increased risk of cardiac arrhythmias. Experimental studies in patients with kidney failure who were treated with intermittent haemodialysis suggest that fast UFNET rates are also associated with ischaemic injury to the heart, brain, kidney and gut. The UFNET rate should be prescribed based on patient body weight in millilitres per kilogramme per hour with close monitoring of patient haemodynamics and fluid balance. Dialysate cooling and sodium modelling may prevent haemodynamic instability and facilitate large volumes of fluid removal in patients with kidney failure who are treated with intermittent haemodialysis, but the effects of this strategy on organ injury are less well studied in critically ill patients treated with continuous kidney replacement therapy. Randomized trials are required to examine whether moderate UFNET rates are associated with a reduced risk of haemodynamic instability, organ injury and improved outcomes in critically ill patients.

Kidney Replacement Therapy for Fluid Management

Emerging evidence from observational studies suggests that both slower and faster net ultrafiltration rates during kidney replacement therapy are associated with increased mortality in critically ill patients with acute kidney injury and fluid overload. Faster rates are associated with ischemic organ injury. The net ultrafiltration rate should be prescribed based on patient body weight in milliliters per kilogram per hour, with close monitoring of patient hemodynamics and fluid balance. Randomized trials are required to examine whether moderate net ultrafiltration rates compared with slower and faster rates are associated with reduced risk of hemodynamic instability, organ injury, and improved outcomes.

Ultrafiltration rate adjusted to body weight and mortality in hemodialysis patients

BACKGROUND AND AIMS

Mortality among hemodialysis patients remains high. An elevated ultrafiltration rate adjusted by weight (UFR/W) has been associated with hypotension and higher risk of death and/or cardiovascular events.

METHODS

We evaluated the association between UFR/W and mortality in 215 hemodialysis patients. The mean follow-up was 28 ± 6.12 months. We collected patientś baseline characteristics and mean UFR/W throughout the follow-up.

RESULTS

Mean UFR/W was 9.0 ± 2,4 and tertiles 7.1 y 10.1 mL/kg/h. We divided our population according to the percentage of sessions with UFR/W above the limits described in the literature associated with increased mortality (10.0 mL/kg/h and 13.0 mL/kg/h). Patients with higher UFR/W were younger, with higher interdialytic weight gain and weight reduction percentage but lower dry, pre and post dialysis weight. Throughout the follow-up, 46 (21.4%) patients died, the majority over 70 years old, diabetic or with cardiovascular disease. There were neither differences regarding mortality between groups nor differences in UFR/W among patients who died and those who did not. Contrary to previous studies, we did not find an association between UFR/W and mortality, maybe due to a higher prevalence in the use of cardiovascular protection drugs and lower UFR/W.

CONCLUSIONS

The highest UFR/W were observed in younger patients with lower weight and were not associated with an increased mortality.

Patient-reported symptoms during dialysis: the effect of pre-dialysis extracellular water and change in extracellular water post-dialysis

Background

Quality of life for haemodialysis (HD) patients may be affected by symptoms during dialysis treatments, and patient groups have highlighted the need to improve post-dialysis fatigue and dialysis-related symptoms. As changes in extracellular water (ECW) may lead to cramps and other symptoms, we wished to determine whether there was an association between ECW and intra-dialytic symptoms.

Methods

We reviewed the hospital records of HD patients who completed a self-reported intra-dialytic symptom questionnaire, using a visual analogue scale, who had contemporaneous pre- and postdialysis bioimpedance ECW measurements adjusted to height (aECW).

Results

We studied dialysis sessions of 506 patients, 314 (62.1%) male, 226 (44.7%) diabetic, mean age 64.6 ± 15.7 years, weight 69.9 ± 17.4 kg, and duration of dialysis treatment 26 (9.6–60.1) months. We divided patients into three groups according to pre-dialysis aECW, and total dialysis symptom scores were greater for those in the lower tertile (25 (10–41) vs middle 18 (8.5–34) vs upper 20 (7–31), p < 0.05). Only feeling cold, dizziness, and low blood pressure were statistically different between the three pre-dialysis aECW groups, and there was no difference in post-dialysis recovery times.

We analysed the effect of the fall in aECW pre-to post-dialysis. Patients in the group with the greatest fall in aECW did not report more intra-dialytic symptoms or longer recovery times.

Conclusion

We found that patients starting dialysis with lower relative ECW were more likely to report intra-dialytic symptoms than those with greater amounts of fluid to remove, and most commonly reported symptoms were associated with intra-vascular volume depletion.

Paradoxical Association Between Intradialytic Blood Pressure Change and Long-Term Mortality with Different Levels of Interdialytic Weight Gain

Background

A greater interdialytic weight gain (IDWG) implies a greater ultrafiltration rate, which might lead to hemodynamic instability and intradialytic blood pressure (BP) change in hemodialysis patients. However, current studies have not explicated the impact of IDWG on the association between intradialytic BP changes and prognosis, especially in patients without cardiac dysfunction and diabetes. In this study, we aimed to explore the relationship between absolute intradialytic BP changes and mortality with different IDWG levels.

Methods

A total of 204 hemodialysis patients (without cardiac dysfunction and diabetes) were included in this prospective observation study, with a mean follow-up of 55.32±20.99 months. Initially, we collected IDWG, IDWG% (percentages according to dry weight), and pre-/post-BPs of 36 consecutive dialysis sessions during three months enrollment. And the average value of them was defined as baseline value. Patients were divided into 3 cohorts according to IDWG% tertiles (<3.3%, 3.3%-4.6%, ≥4.6%). Comparisons between different tertiles were analyzed.

Results

Compared to the low IDWG% group (tertile 1, T1), patients of high IDWG% group (tertile 3, T3) were younger, had higher ultrafiltration rate, less residual kidney function, lower BMI and dry weight, longer dialysis vintage and higher N terminal pro B type natriuretic peptide levels (P<0.05). Correlations were found between IDWG% and intradialytic BP changes. Kaplan-Meier analysis and multivariate Cox regression model adjusted for demographic data, dialysis information and predialysis BPs indicated that greater absolute intradialytic BP changes were associated with worse prognosis in T1 group (P<0.05). While in T3 group, less absolute intradialytic BP changes were associated with higher mortality (P<0.05).

Conclusion

There is a paradoxical association between absolute intradialytic BP changes and long-term mortality with different IDWG levels. Both BP stability and volume balance are crucial to patients' prognosis.

Intradialytic systolic blood pressure variation can predict long-term mortality in patients on maintenance hemodialysis

PURPOSE

It is unclear which time-points of intradialytic blood pressure (BP) best predict prognosis. Thus, it is important to assess the association between different time-points of intradialytic BP and prognosis in clinical practice.

METHODS

We recruited patients who underwent hemodialysis from January 2014 to June 2014. Data about dialysis were collected, including intradialytic BP. Cox regression analysis was performed to examine the association between different time-points of intradialytic BP and clinical events, with a follow-up through December 31, 2019. The primary endpoint was all-cause mortality.

RESULTS

A total of 216 patients were recruited and 62 (30.7%) patients died (6.1 per 100-person year) during the follow-up. Intradialytic SBP varied greatly in fatalities. Univariate and multivariate Cox regression models indicated that the adjusted hazard ratio for death was 1.80 and 5.06 when intradialytic systolic blood pressure (SBP) variation was analyzed in increments of 20 mmHg. Furthermore, we divided intradialytic SBP variation into three categories: < 15 mmHg, 15 ~ 30 mmHg,  ≥ 30 mmHg. Kaplan-Meier analysis indicated that both all-cause mortality and cardiovascular mortality increased significantly for patients with intradialytic SBP variation over 30 mmHg (P = 0.006 and 0.021). Univariate and multivariate Cox regression models indicated that the adjusted hazard ratio for death was 3.78 and 12.62 as intradialytic SBP variation ≥ 30 mmHg vs. intradialytic SBP variation < 15 mmHg.

CONCLUSION

Intradialytic SBP variation, rather than BP of specific intradialytic time-points, has the potential to predict long-term mortality in hemodialysis patients. BP stability is crucial for patients' prognosis.

Intradialytic hypotension and relationship with cognitive function and brain morphometry

Background

The haemodynamic stress brought about by dialysis could justify the loss of structural and functional integrity of the central nervous system (CNS). The main objective of this study was to analyse the relationship between intradialytic hypotension (IDH) and cognitive function and brain morphometry.

Methods

The cross-sectional KIDBRAIN study (Cohort Study of Morphological Changes of the Brain by MRI in Chronic Kidney Disease Patients) included 68 prevalent patients with no history of neurological disorders (cerebrovascular disease and cognitive impairment) undergoing haemodialysis (HD). We analysed 18 non-consecutive dialysis sessions (first three of each month over a 6-month period) and various definitions of IDH were recorded. Global cognitive function (GCF) was assessed using the Mini-Mental State Examination (MMSE) and parameters of structural integrity of the CNS were obtained using volume morphometry magnetic resonance imaging analysis [grey matter (GM), white matter (WM) and hippocampus).

Results

A greater number of sessions with IDH were associated with less volume of WM (r = −0.359,P = 0.003) and hippocampus (r = −0.395, P = 0.001) independent of cardiovascular risk factors according to multivariable linear regression models (β = −0.198, P = 0.046 for WM; β = −0.253, P = 0.017 for hippocampus). The GCF by the MMSE was 27.3 ± 7.3.1 and was associated with WM volume (β = 0.403, P = 0.001) independent of GM and hippocampus volume. Symptomatic IDH was associated with GCF (r = −0.420, P < 0.001) in adjusted analysis (β = −0.339, P = 0.008).

Conclusions

Even when asymptomatic, IDH is associated with a lower WM and hippocampus volume and reduced GCF in patients undergoing HD, thus suggesting greater vulnerability of the brain to the haemodynamic stress that may be generated by a dialysis session.

Heterogeneity of Effect of Net Ultrafiltration Rate among Critically Ill Adults Receiving Continuous Renal Replacement Therapy

INTRODUCTION

In continuous renal replacement therapy (CRRT)-treated patients, a net ultrafiltration (NUF) rate >1.75 mL/kg/h has been associated with increased mortality. However, there may be heterogeneity of effect of NUF rate on mortality, according to patient characteristics.

METHODS

To investigate the presence and impact of heterogeneity of effect, we performed a secondary analysis of the "Randomized Evaluation of Normal versus Augmented Level of Renal Replacement Therapy" (RENAL) trial. Exposure was NUF rate (weight-adjusted fluid volume removed per hour) stratified into tertiles (<1.01 mL/kg/h; 1.01-1.75 mL/kg/h; or >1.75 mL/kg/h). Primary outcome was 90-day mortality. Patients were clustered according to baseline characteristics. Heterogeneity of effect was assessed according to clusters and baseline edema and related to the additional impact of baseline cardiovascular Sequential Organ Failure Assessment (SOFA) score. We excluded patients with missing values for baseline weight and/or treatment duration.

RESULTS

We identified 2 clusters. The largest (cluster 1; n = 941) included more severely ill patients, with more sepsis, more edema, and more vasopressor therapy (all p < 0.001). Compared to the middle tertile, the probability of harm was greater with the high tertile of NUF rate in patients in cluster 1 and in patients with baseline edema (probability of harm, cluster 1: 99.9%; edema: 99.1%). Moreover, higher baseline cardiovascular SOFA score also increased mortality risk with both high and low compared to middle NUF rates in cluster 1 patients and in patients with edema.

CONCLUSIONS

In CRRT patients, both high and low NUF rates may be harmful, especially in those with edema, sepsis, and greater illness severity. Cardiovascular SOFA scores modulate this association. Additional studies are needed to test these hypotheses, and targeted trials of NUF rates based on risk stratification appear justified.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00221013.

Sodium, volume and pressure control in haemodialysis patients for improved cardiovascular outcomes

Chronic volume overload is pervasive in patients on chronic haemodialysis and substantially increases the risk of cardiovascular death. The rediscovery of the three-compartment model in sodium metabolism revolutionizes our understanding of sodium (patho-)physiology and is an effect modifier that still needs to be understood in the context of hypertension and end-stage kidney disease. Assessment of fluid overload in haemodialysis patients is central yet difficult to achieve, because traditional clinical signs of volume overload lack sensitivity and specificity. The highest all-cause mortality risk may be found in haemodialysis patients presenting with high fluid overload but low blood pressure before haemodialysis treatment. The second highest risk may be found in patients with both high blood pressure and fluid overload, while high blood pressure but normal fluid overload may only relate to moderate risk. Optimization of fluid overload in haemodialysis patients should be guided by combining the traditional clinical evaluation with objective measurements such as bioimpedance spectroscopy in assessing the risk of fluid overload. To overcome the tide of extracellular fluid, the concept of time-averaged fluid overload during the interdialytic period has been established and requires possible readjustment of a negative target post-dialysis weight. ²³Na-magnetic resonance imaging studies will help to quantitate sodium accumulation and keep prescribed haemodialytic sodium mass balance on the radar. Cluster-randomization trials (e.g. on sodium removal) are underway to improve our therapeutic approach to cardioprotective haemodialysis management.

Effect of ultrafiltration profiling on outcomes among maintenance hemodialysis patients: a pilot randomized crossover trial

BACKGROUND

More rapid fluid removal during hemodialysis is associated with adverse cardiovascular outcomes and longer dialysis recovery times. The effect of ultrafiltration (UF) profiling, independent of concomitant sodium profiling, on markers of intradialytic hemodynamics and other outcomes has been inadequately studied.

METHODS

Four-phase, blinded crossover trial. Participants (UF rates > 10 mL/h/kg) were assigned in random order to receive hemodialysis with UF profiling (constantly declining UF rate, intervention) vs. hemodialysis with conventional UF (control). Each 3-week 9-treatment period was followed by a 1-week 3-treatment washout period. Participants crossed into each study arm twice (2 phases/arm); 18 treatments per treatment type. The primary outcomes were intradialytic hypotension, pre- to post-dialysis troponin T change, and change from baseline in left ventricular global longitudinal strain. Other outcomes included intradialytic symptoms and blood volume measured-plasma refill (post-dialysis volume status measure), among others. Each participant served as their own control.

RESULTS

On average, the 34 randomized patients (mean age 56 years, 24% female, mean dialysis vintage 6.3 years) had UF rates > 10 mL/h/kg in 56% of treatments during the screening period. All but 2 patients completed the 15-week study (prolonged hospitalization, kidney transplant). There was no significant difference in intradialytic hypotension, troponin T change, or left ventricular strain between hemodialysis with UF profiling and conventional UF. With UF profiling, participants had significantly lower odds of light-headedness and plasma refill compared to hemodialysis with conventional UF.

CONCLUSIONS

Ultrafiltration (UF) profiling did not reduce the odds of treatment-related cardiac stress but did reduce the odds of light-headedness and post-dialysis hypervolemia.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT03301740 (registered October 4, 2017).

Association between pill burden and interdialytic weight gain in patients with hemodialysis: A multi-center cross-sectional study

High daily pill burden affects quality of life and mortality. High interdialytic weight gain (IDWG) is associated with increased mortality. We examined the association between pill burden and IDWG in hemodialysis patients. This cross-sectional study was conducted in six dialysis centers in Japan in June 2017. The exposure was the number of daily tablets, and outcome was defined as 1 day of relative IDWG divided by post-dialysis weight from the previous session. Among 188 outpatients (mean age, 68.7 [SD, 10.3] years; men, 67.0%; median dialysis vintage, 76.0 [interquartile range, 36.5, 131.5] months), the mean number of daily tablets was 19.7 ± 9.9, and mean relative weight gain was 3.5 ± 1.2%. Multiple linear regression analysis showed a regression coefficient of 0.021 (95% confidence interval: 0.004-0.039), indicating that one additional tablet prescription increased the IDWG by 0.021%. In hemodialysis patients, the daily pill burden was a significant, independent risk for increased relative IDWG.

Electrophysiological insights into the relationship between calcium dynamics and cardiomyocyte beating function in chronic hemodialysis treatment

For patients in which the Ca²⁺ concentration of dialysis fluid is lower than that in plasma, chronic hemodialysis treatment often leads to cardiac beating dysfunction. By applying these conditions to an electrophysiological mathematical model, we evaluated the impact of body fluid Ca²⁺ dynamics during treatment on cardiomyocyte beating and, moreover, explored measures that may prevent cardiomyocyte beating dysfunction. First, Ca²⁺ concentrations in both plasma and interstitial fluid were decreased with treatment time, which induced both a slight decline in beating rhythm on a sinoatrial nodal cell and a wane in contraction force on a ventricular cell. These simulated results were in agreement with clinical observations. Next, a relationship between the intracellular Ca²⁺ concentration and ion current dynamics of ion transporters were examined to elucidate the mechanism underlying cardiomyocyte beating dysfunction. The inward current of the Na/Ca exchanger (NCX) increased with a decrease in Ca²⁺ concentration in interstitial fluid and induced a reduction in intracellular Ca²⁺ concentration during treatment. Furthermore, the decline in intracellular Ca²⁺ concentration reduced the contraction force. These findings implied that ion transport through the NCX is a dominant factor that induces cardiomyocyte beating dysfunction during hemodialysis. Finally, the replenishment of Ca²⁺ or application of an NCX inhibitor during treatment suppressed the decrease in intracellular Ca²⁺ concentration and contributed to the stabilization of cardiomyocyte beating function. In summary, the clinical implementation of hepatically cleared NCX inhibitor may be a suitable approach to improving the quality of life for patients on chronic hemodialysis.

The impact of home hemodialysis in children with severe cardiac failure

When faced with patients with deteriorating cardiac disease, nephrologists tend to accept that heart disease is unmodifiable, accepting mediocrity and opting for stabilization. Likewise cardiac patients with persistent renal failure are presented with a poor renal prognosis and prepared for renal transplantation. We present three dialysis dependent children with moderate-to-severe cardiac failure in whom home hemodialysis normalized the cardiac function and restored renal function. These cases highlight the medical benefits of home hemodialysis in severe cardio-renal cases but not without acknowledgement of the resource, commitment, and safety challenges that accompanies them.

Association between Ultrafiltration Rate and Clinical Outcome Is Modified by Muscle Mass in Hemodialysis Patients

BACKGROUND

The association between ultrafiltration rate (UFR) and mortality may be affected by the muscle mass or volume status in hemodialysis (HD) patients. However, there is an absence of data regarding this association.

METHODS

We performed an observational study on patients (≥18 years old) who had been on HD for at least 3 months. A body composition monitor (BCM) was used for baseline bioimpedance analysis measurement. The primary composite outcome was defined as the time to death or the first cardiovascular event.

RESULTS

The median (interquartile range) UFR, volume excess measured by the BCM, and lean tissue index (LTI) (calculated as lean tissue mass/height2) were 11.4 (8.0-15.0) mL/h/kg, 2.4 (1.4-4.1) L, and 12.5 (10.4-14.4) kg/m2, respectively. During 284 person-years of follow-up, the primary outcome occurred in 44 of the 167 patients (26%). Higher UFR was associated with an increased outcome of death or cardiovascular event; the adjusted hazard ratio (HR) was 1.044 (95% confidence interval [CI]: 1.006-1.083). This association remained consistent even after adjusting for volume excess. However, the association between UFR and the primary outcome was modified by LTI (pinteraction = 0.027); the association was significant in patients with LTI < 12.5 kg/m2, and the HR (95% CI) was 1.050 (1.001-1.102).

CONCLUSION

Higher UFR was associated with an increased risk of a composite outcome of death or cardiovascular event regardless of volume status in HD patients. However, muscle mass may modify the association between higher UFR and increased risk of a composite outcome.

Ultrafiltration rates and intradialytic hypotension: A case-control sampling of pooled haemodialysis data

BACKGROUND

Intradialytic hypotension (IDH) is one of the most critical adverse events during maintenance haemodialysis. Previous studies reported the association of fluid removal rate with the occurrence of IDH.

OBJECTIVE

We aimed to identify the optimal threshold of ultrafiltration rate to prevent the occurrence of IDH events. DESIGN, PARTICIPANTS AND MEASUREMENTS: Prognostic factor research with a retrospective case-control design was conducted. Patient data were gathered from four haemodialysis units from January to December 2017. All the haemodialysis records were independently justified, whether IDH occurred or not, based on the standard definition. A total of 10 haemodialysis sessions were sampled from each patient's pool based on the incidence of events. The association of ultrafiltration rates and IDH events was explored by multivariable multilevel logistic regression.

RESULTS

A total of 1080 haemodialysis sessions from 108 patients were included: 149 (13.8%) with IDH and 931 (86.2%) without IDH. After adjusting for all pre-specified risk factors and imbalance baselines, the odds ratio of IDH were 1.22 (95% confidence interval [CI]: 0.59, 2.52) for rate 10-12 ml/kg/h; 2.52 (95% CI: 1.20, 5.29) for rate 12-14 ml/kg/h; 4.02 (95% CI: 1.61, 10.03) for rate 14-16 ml/kg/h; and 7.41 (95% CI: 2.53, 21.68) for rate >16 ml/kg/h comparing to the referent rate of <10 ml/kg/h.

CONCLUSION

The ultrafiltration rate should be limited to 12 ml/kg/h. If a higher rate of fluid removal was indicated, it should not exceed 16 ml/kg/h to avoid the occurrence of IDH.

Monitoring for intradialytic hypotension: An audit of nursing practice

BACKGROUND

Intradialytic hypotension (IDH) is one of the most common complications associated with haemodialysis (HD), yet the frequency of patient assessment by nurses varies in practice. We sought to measure the frequency of nursing assessments before, during and after HD and to identify any predictors of IDH.

OBJECTIVES

To audit the frequency, nursing management and contributing factors of IDH.

DESIGN

A prospective clinical audit was undertaken over 4 weeks.

PARTICIPANTS

Nurses completed audit sheets on 132 patients at three chronic HD units.

MEASUREMENTS

The audit tool consisted of 34 questions related to demographics, HD prescription, frequency of monitoring and nursing interventions.

RESULTS

A total of 1584 sessions were performed with 876 (55.3%) audits returned, of which 452 were useable. There were 74 actual episodes of IDH, and a further 72 potential episodes may have been prevented due to nursing intervention. Most nurses reported assessing patients before starting HD and as required before an actual or potential IDH event (n = 85; 63%); few hourly assessments were performed. Predictors of IDH were systolic blood pressure ≤140 mmHg, having more than four comorbidities, dialysate temperature > 36°C, calcium < 1.3 mmol/L and a shorter dialysis session (3.0-4.5 h). These predictors explained 14.1% of the variance in hypotensive episodes during HD.

CONCLUSION

This clinical audit highlighted the importance of assessing blood pressure trends during HD to preemptively intervene before IDH developing. The audit has resulted in a practice change to hourly assessments. Follow-up audits of practice should occur.

An update review of intradialytic hypotension: concept, risk factors, clinical implications and management

Intradialytic hypotension (IDH) is a frequent and serious complication of chronic haemodialysis, linked to adverse long-term outcomes including increased cardiovascular and all-cause mortality. IDH is the end result of the interaction between ultrafiltration rate (UFR), cardiac output and arteriolar tone. Thus excessive ultrafiltration may decrease the cardiac output, especially when compensatory mechanisms (heart rate, myocardial contractility, vascular tone and splanchnic flow shifts) fail to be optimally recruited. The repeated disruption of end-organ perfusion in IDH may lead to various adverse clinical outcomes affecting the heart, central nervous system, kidney and gastrointestinal system. Potential interventions to decrease the incidence or severity of IDH include optimization of the dialysis prescription (cool dialysate, UFR, sodium profiling and high-flux haemofiltration), interventions during the dialysis session (midodrine, mannitol, food intake, intradialytic exercise and intermittent pneumatic compression of the lower limbs) and interventions in the interdialysis period (lower interdialytic weight gain and blood pressure–lowering drugs). However, the evidence base for many of these interventions is thin and optimal prevention and management of IDH awaits further clinical investigation. Developing a consensus definition of IDH will facilitate clinical research. We review the most recent findings on risk factors, pathophysiology and management of IDH and, based on this, we call for a new consensus definition of IDH based on clinical outcomes and define a roadmap for IDH research.

No evidence of a legacy effect on survival following randomization to extended hours dialysis in the ACTIVE Dialysis trial

AIM

Extended hours haemodialysis is associated with superior survival to standard hours. However, residual confounding limits the interpretation of this observation. We aimed to determine the effect of a period of extended hours dialysis on long-term survival among participants in the ACTIVE Dialysis trial.

METHODS

Two-hundred maintenance haemodialysis recipients were randomized to extended hours dialysis (median 24 h/wk) or standard hours dialysis (median 12 h/wk) for 12 months. Further pre-specified observational follow up occurred at 24, 36 and 60 months. Vital status and modality of renal replacement therapy were ascertained.

RESULTS

Over the 5 years, 38 participants died, 30 received a renal transplant, and 6 were lost to follow up. Total weekly dialysis hours did not differ between standard and extended groups during the follow-up period (14.1 hours [95%CI 13.4-14.8] vs 14.8 hours [95%CI 14.1-15.6]; P = .16). There was no difference in all-cause mortality (hazard ratio for extended hours 0.91 [95%CI 0.48-1.72]; P = .77). Similar results were obtained after censoring participants at transplantation, and after adjusting for potential confounding variables. Subgroup analysis did not reveal differences in treatment effect by region, dialysis setting or vintage (P-interaction .51, .54, .12, respectively).

CONCLUSION

Twelve months of extended hours dialysis did not improve long-term survival nor affect dialysis hours after the intervention period. An urgent need remains to further define the optimal dialysis intensity across the broad range of dialysis recipients.

Association between extracellular volume control and survival in patients on short daily haemodialysis

Background

Fluid overload (FO) assessed by bioimpedance spectroscopy (BIS) is associated with higher mortality risk in maintenance haemodialysis (HD). The aim was to assess if a better management of FO through short daily haemodialysis (SDHD) could improve survival.

Methods

Retrospective analysis of patients who were on HD 3 sessions/week for at least 3 months and shifted to in-centre SDHD (5 or 6 sessions/week, 2 to 3 h/session) between July 2012 and June 2016 at 23 dialysis units in Brazil. The 12-month risk of death was analysed according to the predialysis hydration status measured before and 6 months after initiation of SDHD. Predialysis hydration status was considered adequate when FO ≤15% of extracellular volume.

Results

A total of 297 patients on SDHD were included in the analysis. Their median age was 57 (IQR 45–67) years, 62% were males, 44% diabetics, 57% on 6 dialysis sessions/week, with a median session duration of 130 (IQR 120–150) minutes. BIS assessment at initiation of the SDHD regimen was performed in 220 patients and FO > 15% was found in 46.4%. Twelve-month survival rates for those with FO ≤15 and > 15% before initiating SDHD were 87.4 and 88.0%, respectively (P = 0.92). BIS analysis when completing 6 months on SDHD were available for 229 patients, 26.6% with FO > 15%. The survival rates for the next 12 months (from the 6th to the 18th month of follow-up) for those with FO ≤15 and > 15% were 91.0 and 72.0%, respectively (P = 0.0006). In a Cox regression model, after adjustment for demographic, clinical and laboratory variables, FO ≤ 15% persisted associated with a lower mortality risk (hazard ratio 0.34, 95%CI 0.13–0.87).

Conclusions

Moving from conventional HD to SDHD was associated with better control of excessive extracellular volume. Patients who reached or maintained predialysis fluid overload ≤15% after initiating SDHD presented a lower risk of death.