Longer treatment time and slower ultrafiltration in hemodialysis: Associations with reduced mortality in the DOPPS

Correlation between ultrafiltration rate and hemoglobin level and erythropoietin response in hemodialysis patients

This study aimed to investigate the correlation between ultrafiltration rate (UFR) and hemoglobin levels and erythropoietin (EPO) response in patients receiving maintenance hemodialysis (MHD). 225 MHD patients were divided into three groups according to the UFR: < 10 ml/h/kg, 10-13 ml/h/kg, and >13 ml/h/kg. Clinical parameters and prognosis were compared among the groups. Multiple linear correlation and regression analyses were conducted. SPSS 26.0 (IBM, Chicago, IL, USA) was used to analyze all statistics. The UFR < 10 ml/h/kg group was older than the other groups (p < 0.05). The UFR > 13 ml/h/kg group had the highest SpKt/V (p < 0.05), monthly EPO dose/weight (p < 0.001), and EPO resistance index (p < 0.001), as well as the lowest dry weight (p < 0.001), BMI (p < 0.001), hemoglobin (p < 0.001), hematocrit (p < 0.05), and red blood cell count (p < 0.05). Multiple linear regression analysis showed that sex, dry weight, UFR, calcium, phosphorus, albumin, and C-reactive protein levels were associated with hemoglobin levels. Multivariate logistic regression analysis revealed that a higher UFR was associated with lower hemoglobin levels, while male sex and higher levels of calcium and albumin were associated with higher hemoglobin levels. High UFR is associated with more severe anemia and EPO resistance in MHD. This study provides new insights into anemia management in patients undergoing hemodialysis.

Development and validation of a model for predicting the risk of cardiovascular events in maintenance hemodialysis patients

The mortality rates for patients undergoing hemodialysis (HD) remain unacceptably high compared to the general population, and more specific information about the causes of death is not known. The study aimed to develop and validate a risk prediction model that uses common clinical factors to predict the probability of cardiovascular events in maintenance hemodialysis (MHD) patients. The study involved 3488 adult patients who received regular scheduled hemodialysis treatment at 20 hemodialysis centers in southwest China between June 2015 and August 2020, with follow-up until August 2021. The optimal parameter set was identified by multivariable Cox regression analyses and Cross-LASSO regression analyses and was used to establish a nomogram for predicting the risk of cardiovascular events in maintenance hemodialysis patients at 3 and 5 years. The performance of the model was evaluated using the consistency index (Harrell's C-index), the area under the receiver operating characteristic (ROC) curve, and calibration plots. The model was validated by tenfold cross-validation and bootstrapping with 1000 resamples. In the derivation cohort, the model yields an AUC of 0.764 [95% confidence interval (CI), 0.737-0.790] and 0.793 [CI, 0.757-0.829] for predicting the risk of cardiovascular events of MHD patients at 3 and 5 years. In the internal validation cohort AUC of 0.803 [95% CI, 0.756-0.849], AUC of 0.766 [95% CI, 0.686-0.846], and the external validation cohort AUC of 0.826 [95% CI, 0.765-0.888], AUC of 0.817 [95% CI, 0.745-0.889] at 3 and 5 years. The model's calibration curve is close to the ideal diagonal. By tenfold cross-validation analyses, the 3- and 5-year risk of cardiovascular events (AUC 0.732 and 0.771, respectively). By the bootstrap resampling method, the derivation cohort and validation cohort (Harrell's C-index 0.695 and 0.667, respectively) showed good uniformity with the model. The constructed model accurately predicted cardiovascular events of MHD patients in the 3rd and 5th years after dialysis. And the further research is needed to determine whether use of the risk prediction tool improves clinical outcomes.

Myocardial markers are highly altered by higher rates of fluid removal during hemodialysis

INTRODUCTION

Although hemodialysis is lifesaving in patients with kidney failure extensive interdialytic weight gain (IDWG) between dialyses worsens the prognosis. We recently showed a strong correlation between IDWG and predialytic values of cardiac markers. The aim of the present study was to evaluate if the cardiac markers N-terminal pro-B-type natriuretic peptide (proBNP) and troponin T were influenced by IDWG and speed of fluid removal (ultrafiltration-rate).

METHODS

Twenty hemodialysis patients performed in total 60 hemodialysis (three each). Predialytic values of proBNP and troponin T and changes from predialysis to 180 min hemodialysis (180-0 min) were compared with the IDWG calculated in percent of body weight. The ultrafiltration-rate was adjusted (UF-rateadj ) to IDWG: (100 × weight gain between dialysis [kg])/(estimated body dry weight [kg] × length of hemodialysis session [hours]).

RESULTS

UF-rateadj correlated (Spearman) with (1) predialytic values of IDWG (r = 0.983, p < 0.001), proBNP (r = 0.443, p < 0.001), and troponin T (r = 0.296, p = 0.025); and (2) differences in proBNP180-0min (r = 0.572, p < 0.001) and troponin T180-0min (r = 0.400, p = 0.002). UF-ratesadj above a breakpoint of 0.60 caused more release of proBNP180-0min (p = 0.027). Remaining variables in multiple regression analysis with ProBNP180-0min as dependent factor were predialytic proBNP (p < 0.001) and the ultrafiltration-rate (p < 0.001).

CONCLUSION

Higher UF-rateadj during dialysis was correlated to increased levels of cardiac markers. Data support a UF-rateadj lower than 0.6 to limit such increase. Further studies may confirm if limited fluid intake and a lower UF-rateadj should be recommended to prevent cardiac injury during dialysis.

Extracorporeal Techniques in Kidney Failure

During the last decades, various strategies have been optimized to enhance clearance of a variable spectrum of retained molecules to ensure hemodynamic tolerance to fluid removal and improve long-term survival in patients affected by kidney failure. Treatment effects are the result of the interaction of individual patient characteristics with device characteristics and treatment prescription. Historically, the nephrology community aimed to provide adequate treatment, along with the best possible quality of life and outcomes. In this article, we analyzed blood purification techniques that have been developed with their different characteristics.

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.

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.

Impact of haemodialysis hours on outcomes in older patients

AIM

Previous studies report an association between longer haemodialysis treatment sessions and improved survival. Worldwide, there is a trend to increasing age among prevalent patients receiving haemodialysis. This analysis aimed to determine whether the mortality benefit of longer haemodialysis treatment sessions diminishes with increasing age.

METHODS

This was a retrospective cohort study of people who first commenced thrice-weekly haemodialysis aged ≥65 years, reported to the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry from 2005 to 2015, included from 90 days after dialysis start. The primary outcome was all-cause mortality. Cox regression analysis was performed with haemodialysis session duration the exposure of interest.

RESULTS

Of 8224 people who commenced haemodialysis as their first treatment for kidney failure aged ≥65 years during this period, 4727 patients died. Longer dialysis hours per session was associated with a decreased risk of death in unadjusted analyses [hazard ratio, HR, for ≥5 h versus 4 to <4.5 h: 0.81 (0.75-0.88, p < .001)]. Patients having longer dialysis sessions were younger but had greater co-morbidity. In an adjusted model including age and other variables, the survival benefit of longer hours was only partially attenuated [HR for previous comparison: 0.75 (0.69-0.82, p < .001)], and no interaction between age and hours was demonstrated (p = .89).

CONCLUSION

The apparent survival benefit associated with longer haemodialysis session length appears to be preserved in patients 65 years or older. In practice, the benefit of longer dialysis hours should be carefully weighed against other factors in this patient group.

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.

Cardiovascular Effects of Home Dialysis Therapies: A Scientific Statement From the American Heart Association

Cardiovascular disease is the leading cause of morbidity and mortality in patients with end-stage kidney disease. Currently, thrice-weekly in-center hemodialysis for 3 to 5 hours per session is the most common therapy worldwide for patients with treated kidney failure. Outcomes with thrice-weekly in-center hemodialysis are poor. Emerging evidence supports the overarching hypothesis that a more physiological approach to administering dialysis therapy, including in the home through home hemodialysis or peritoneal dialysis, may lead to improvement in several cardiovascular risk factors and cardiovascular outcomes compared with thrice-weekly in-center hemodialysis. The Advancing American Kidney Health Initiative, which has a goal of increasing the use of home dialysis, is aligned with the American Heart Association's 2024 mission to champion a full and healthy life and health equity. We conclude that incorporation of interdisciplinary care models to increase the use of home dialysis therapies in an equitable manner will contribute to the ultimate goal of improving outcomes for patients with kidney failure and cardiovascular disease.

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.

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.

Total body water/fat-free mass ratio as a valuable predictive parameter for mortality in maintenance hemodialysis patients

Hydration of fat-free mass (FFM), defined as the ratio of total body water (TBW) to FFM (TBW/FFM), is stable at 0.739 in adult mammals. However, an increase in the TBW/FFM ratio is common in hemodialysis (HD) patients. This study aimed to evaluate the determinants of TBW/FFM and investigate its predictive value for the prognosis of all-cause mortality in HD patients. We enrolled patients undergoing maintenance HD between July 2020 and May 2021. All patients were prospectively followed until death, HD dropout, or until the end of the study (November 1, 2021). A forward stepwise multivariable linear regression analyses was performed to test the independent relationship between TBW/FMM and other clinical variables. Receiver operating characteristic (ROC) analysis was used to discriminate the TBW/FFM with respect to 180-day mortality. Of the 106 patients, 42 had elevated TBW/FFM levels. Multiple linear regression analysis revealed that the TBW/FFM ratio was significantly associated with extracellular water (ECW)/TBW (standardized regression coefficient [β = 1.131, P < .001], phase angle (PhA) [β = 0.453, P < .001], and sex (β = 0.440, P < .001). We calculated the ROC curve (AUC) of TBW/FFM, ECW, ECW/TBW, and intracellular water (ICW) to compare the discriminatory capacities of these parameters in predicting 180-day mortality. The AUC for TBW/FFM (AUC = 0.849; 95% CI, 0.745-0.953) exhibited better discriminatory potential than ECW (AUC = 0.562; 0.410-0.714), although it had a similar predictive potential as the ECW/TBW ratio (AUC = 0.831; 0.731-0.932). High TBW/FFM can be used as a valuable prognostic index for predicting all-cause mortality in patients on HD.

International Icodextrin Use and Association with Peritoneal Membrane Function, Fluid Removal, Patient and Technique Survival

BACKGROUND

Icodextrin has been shown in randomized controlled trials to benefit fluid management in peritoneal dialysis (PD). We describe international icodextrin prescription practices and their relationship to clinical outcomes.

METHODS

We analyzed data from the prospective, international PDOPPS, from Australia/New Zealand, Canada, Japan, the United Kingdom, and the United States. Membrane function and 24-hour ultrafiltration according to icodextrin and glucose prescription was determined at baseline. Using an instrumental variable approach, Cox regression, stratified by country, was used to determine any association of icodextrin use to death and permanent transfer to hemodialysis (HDT), adjusted for demographics, comorbidities, serum albumin, urine volume, transplant waitlist status, PD modality, center size, and study phase.

RESULTS

Icodextrin was prescribed in 1986 (35%) of 5617 patients, >43% of patients in all countries, except in the United States, where it was only used in 17% and associated with a far greater use of hypertonic glucose. Patients on icodextrin had more coronary artery disease and diabetes, longer dialysis vintage, lower residual kidney function, faster peritoneal solute transfer rates, and lower ultrafiltration capacity. Prescriptions with or without icodextrin achieved equivalent ultrafiltration (median 750 ml/d [interquartile range 300-1345 ml/d] versus 765 ml/d [251-1345 ml/d]). Icodextrin use was not associated with mortality (HR=1.03; 95% CI, 0.72 to 1.48) or HDT (HR 1.2; 95% CI, 0.92 to 1.57).

CONCLUSIONS

There are large national and center differences in icodextrin prescription, with the United States using significantly less. Icodextrin was associated with hypertonic glucose avoidance but equivalent ultrafiltration, which may affect any potential survival advantage or HDT.

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.

Switching from high-flux dialysis to hemodiafiltration: Cost-consequences for patients, providers, and payers

Hemodiafiltration (HDF) achieves a more efficient reduction of the uremic toxic load compared to standard high-flux hemodialysis (HF-HD) by virtue of the combined diffusive and convective clearances of a broad spectrum of uremic retention solutes. Clinical trials and registry data suggest that HDF improves patient outcomes. Despite the acknowledged need to improve survival rates of dialysis patients and the survival benefit HDF offers, there is little to no utilization in some countries (such as the US) in prescribing HDF to their patients. In this analysis, we present the healthcare value-based case for HDF (relative to HF-HD) from the patient, provider, and payor perspectives. The improved survival and reduced morbidity observed in studies conducted outside the US, as well as the reduced hospitalization, are attractive for each stakeholder. We also consider the potential barriers to greater utilization of HDF therapies, including unfounded concerns regarding additional costs of HDF, e.g., for the preparation and microbial testing of quality of substitution fluids. Ultrapure fluids are easily attainable and prepared from dialysis fluids using established "online" (OL) technologies. OL-HDF has matured to a level whereby little additional effort is required to safely implement it as all modern machine systems are today equipped with the OL-HDF functionality. Countries already convinced of the advantages of HF-HD are thus well positioned to make the transition to OL-HDF to achieve further clinical and associated economic benefits. Healthcare systems struggling to cope with the increasing demand for HD therapies would therefore, like patients, be beneficiaries in the long term with increased usage of OL-HDF for end stage kidney disease patients.

Dialysis-Associated Nonarteritic Anterior Ischemic Optic Neuropathy: A Case Series and Review

BACKGROUND

Dialysis-associated nonarteritic ischemic optic neuropathy (DA-NAION) occurs secondary to intradialytic hypotension often with catastrophic consequences and is one of the rare situations where NAION can recur in the same eye. We describe 3 cases of DA-NAION associated with hypotension, review the current literature on DA-NAION, and provide recommendations for decreasing the risk of intradialytic hypotension.

METHODS

In addition to describing 3 cases of DA-NAION, PubMed was searched for all reports of DA-NAION in adults with documented episodes of hypotension preceding the onset of NAION. A total of 50 eyes of 31 patients were included. Age, visual acuity at presentation, rate of bilateral involvement at presentation, sequential involvement of the fellow eye, and recurrence of NAION in the same eye were analyzed.

RESULTS

We found that most cases of DA-NAION occur in relatively young patients (47.7 ± 14.7 years) with a high rate of bilateral involvement at presentation (23%) and bilateral sequential involvement (39%). Vision loss is severe with 64% of patients presenting with 20/200 acuity or worse in the involved eye and 19% of patients with final visual acuity of 20/200 or worse in both eyes. 3 patients (9.7%) had recurrence of NAION in the previously affected eye.

CONCLUSIONS

Neuro-ophthalmologists have an important role in identifying patients who have suffered DA-NAION and communicating their findings to nephrologists to minimize the chance of involvement of the fellow eye and recurrence in the same eye. Intradialytic blood pressure must be closely monitored, and fluid balance, dialysate composition, and dialysis protocol must be optimized to prevent occurrence of intradialytic hypotension, which is the culprit for DA-NAION.

Estimated Glomerular Filtration Rate in Chronic Kidney Disease: A Critical Review of Estimate-Based Predictions of Individual Outcomes in Kidney Disease

Chronic kidney disease (CKD) is generally regarded as a final common pathway of several renal diseases, often leading to end-stage kidney disease (ESKD) and a need for renal replacement therapy. Estimated GFR (eGFR) has been used to predict this outcome recognizing its robust association with renal disease progression and the eventual need for dialysis in large, mainly cross-sectional epidemiological studies. However, GFR is implicitly limited as follows: (1) GFR reflects only one of the many physiological functions of the kidney; (2) it is dependent on several non-renal factors; (3) it has intrinsic variability that is a function of dietary intake, fluid and cardiovascular status, and blood pressure especially with impaired autoregulation or medication use; (4) it has been shown to change with age with a unique non-linear pattern; and (5) eGFR may not correlate with GFR in certain conditions and disease states. Yet, many clinicians, especially our non-nephrologist colleagues, tend to regard eGFR obtained from a simple laboratory test as both a valid reflection of renal function and a reliable diagnostic tool in establishing the diagnosis of CKD. What is the validity of these beliefs? This review will critically reassess the limitations of such single-focused attention, with a particular focus on inter-individual variability. What does science actually tell us about the usefulness of eGFR in diagnosing CKD?

High volume online post-dilution hemodiafiltration: how relevant is it in chronic kidney disease?

Online hemodiafiltration is potentially a superior mode of dialysis compared to conventional hemodialysis. However, prospective randomized controlled trials have failed to demonstrate such superiority. Post-hoc analyses of these trials have indicated that high volume post-dilution hemodiafiltration is associated with lower death rates than conventional dialysis. This study discusses whether the lower death rates ascribed to high volume hemodiafiltration are linked to convection volume or the time on dialysis needed to achieve high convection volumes.

Medium Cut-Off Versus High-Flux Hemodialysis Membranes and Clinical Outcomes: A Cohort Study Using Inverse Probability Treatment Weighting

Rationale & Objective

This study investigated the effects on patients’ outcomes of using medium cutoff (MCO) versus high-flux (HF) dialysis membranes.

Study Design

A retrospective, observational, multicenter, cohort study.

Setting & Participants

Patients aged greater than 18 years receiving hemodialysis at the Baxter Renal Care Services dialysis network in Colombia. The inception of the cohort occurred from September 1, 2017, to November 30, 2017, with follow-up to November 30, 2019.

Exposure

The patients were divided into 2 cohorts according to the dialyzer used at the inception: (1) MCO membrane or (2) HF membrane.

Outcomes

Primary outcomes were the hospitalization rate from any cause and hospitalization days per patient-year. Secondary outcomes were acute cardiovascular events and mortality rates from any cause and secondary to cardiovascular causes. Laboratory parameters were assessed throughout the 2-year follow-up period.

Analytical Approach

Descriptive statistics were used to report population characteristics. Inverse probability of treatment weighting was applied to each group before analysis. All categorical variables were compared using Pearson’s χ² test, and continuous variables were analyzed with the t test. Baseline differences between groups with a value of >10% were considered clinically meaningful. Laboratory variables were measured at 5 consecutive time points. A between-patient effect was analyzed using a split-plot factorial analysis of variance.

Results

The analysis included 1,098 patients, of whom 564 (51.3%) were dialyzed with MCO membranes and 534 (48.7%) with HF membranes. Patients receiving hemodialysis with MCO membranes had a lower all-cause hospitalization incidence rate (IR) per patient-year (IR = 0.93; 95% CI, 0.82-1.03) than those receiving hemodialysis with HF membranes (IR = 1.13; 95% CI, 0.96-1.30), corresponding to a significant incident rate ratio (MCO/HF) of 0.82 (95% CI, 0.68-0.99; P = 0.04). The frequency of nonfatal cardiovascular events showed statistical significance, with a lower incidence in the MCO group (incident rate ratio = 0.66; 95% CI, 0.46-0.96; P = 0.03). No statistically significant differences in all-cause time until death were observed (P = 0.48). Albumin levels were similar between the 2 dialyzer cohorts.

Limitations

Despite the robust statistical analysis, there remains the possibility that unmeasured variables may still generate residual imbalance and, therefore, skew the results.

Conclusions

The incidences of hospitalization and cardiovascular events in patients receiving hemodialysis were lower when dialyzed with MCO membranes than HF membranes. A randomized controlled trial would be desirable to confirm these results.

Trial Registration

Clinical Trials.gov, ISRCTN12403265.

Choices in hemodialysis therapies: variants, personalized therapy and application of evidence-based medicine

The extent of removal of the uremic toxins in hemodialysis (HD) therapies depends primarily on the dialysis membrane characteristics and the solute transport mechanisms involved. While designation of ‘flux’ of membranes as well toxicity of compounds that need to be targeted for removal remain unresolved issues, the relative role, efficiency and utilization of solute removal principles to optimize HD treatment are better delineated. Through the combination and intensity of diffusive and convective removal forces, levels of concentrations of a broad spectrum of uremic toxins can be lowered significantly and successfully. Extended clinical experience as well as data from several clinical trials attest to the benefits of convection-based HD treatment modalities. However, the mode of delivery of HD can further enhance the effectiveness of therapies. Other than treatment time, frequency and location that offer clinical benefits and increase patient well-being, treatment- and patient-specific criteria may be tailored for the therapy delivered: electrolytic composition, dialysate buffer and concentration and choice of anticoagulating agent are crucial for dialysis tolerance and efficacy. Evidence-based medicine (EBM) relies on three tenets, i.e. clinical expertise (i.e. doctor), patient-centered values (i.e. patient) and relevant scientific evidence (i.e. science), that have deviated from their initial aim and summarized to scientific evidence, leading to tyranny of randomized controlled trials. One must recognize that practice patterns as shown by Dialysis Outcomes and Practice Patterns Study and personalization of HD care are the main driving force for improving outcomes. Based on a combination of the three pillars of EBM, and particularly on bedside patient–clinician interaction, we summarize what we have learned over the last 6 decades in terms of best practices to improve outcomes in HD patients. Management of initiation of dialysis, vascular access, preservation of kidney function, selection of biocompatible dialysers and use of dialysis fluids of high microbiological purity to restrict inflammation are just some of the approaches where clinical experience is vital in the absence of definitive scientific evidence. Further, HD adequacy needs to be considered as a broad and multitarget approach covering not just the dose of dialysis provided, but meeting individual patient needs (e.g. fluid volume, acid–base, blood pressure, bone disease metabolism control) through regular assessment—and adjustment—of a series of indicators of treatment efficiency. Finally, in whichever way new technologies (i.e. artificial intelligence, connected health) are embraced in the future to improve the delivery of dialysis, the human dimension of the patient–doctor interaction is irreplaceable. Kidney medicine should remain ‘an art’ and will never be just ‘a science’.

Informed decision-making in delivery of dialysis: combining clinical outcomes with sustainability

As the prevalence of chronic kidney disease is expected to rise worldwide over the next decades, provision of renal replacement therapy (RRT), will further challenge budgets of all healthcare systems. Most patients today requiring RRT are treated with haemodialysis (HD) therapy and are elderly. This article demonstrates the interdependence of clinical and sustainability criteria that need to be considered to prepare for the future challenges of delivering dialysis to all patients in need. Newer, more sustainable models of high-value care need to be devised, whereby delivery of dialysis is based on value-based healthcare (VBHC) principles, i.e. improving patient outcomes while restricting costs. Essentially, this entails maximizing patient outcomes per amount of money spent or available. To bring such a meaningful change, revised strategies having the involvement of multiple stakeholders (i.e. patients, providers, payers and policymakers) need to be adopted. Although each stakeholder has a vested interest in the value agenda often with conflicting expectations and motivations (or motives) between each other, progress is only achieved if the multiple blocs of the delivery system are advanced as mutually reinforcing entities. Clinical considerations of delivery of dialysis need to be based on the entire patient disease pathway and evidence-based medicine, while the non-clinical sustainability criteria entail, in addition to economics, the societal and ecological implications of HD therapy. We discuss how selection of appropriate modes and features of delivery of HD (e.g. treatment modalities and schedules, selection of consumables, product life cycle assessment) could positively impact decision-making towards value-based renal care. Although the delivery of HD therapy is multifactorial and complex, applying cost-effectiveness analyses for the different HD modalities (conventional in-centre and home HD) can support in guiding payability (balance between clinical value and costs) for health systems. For a resource intensive therapy like HD, concerted and fully integrated care strategies need to be urgently implemented to cope with the global demand and burden of HD therapy.

High ultrafiltration rate induced intradialytic hypotension is a predictor for cardiac remodeling: a 5-year cohort study

BACKGROUND

Intradialytic-hypotension (IDH) is a common complication of hemodialysis. High ultrafiltration rate (UFR) might lead to IDH. However, the relationships between UFR, IDH, and cardiac remodeling among hemodialysis patients in the long-term have not been deeply explored.

METHODS

This retrospective cohort study collected clinical and echocardiographic data. Patients were enrolled from 1 January 2014 to 31 March 2014 and were followed-up for 5-year. Those who suffered from more than four hypotensive events during three months (10% of dialysis treatments) were defined as the IDH group. Subgroup analysis was done according to the UFR of 10 ml/h/kg. Associations between UFR, IDH, and alterations of cardiac structure/function were analyzed.

RESULTS

Among 209 patients, 96 were identified with IDH (45.9%). The survival rate of IDH patients was lower than that of no-IDH patients (65.5% vs. 81.4%, p = .005). In IDH group, decreased ejection fraction (EF), larger left atrium diameter index (LADI), and left ventricular mass index (LVMI) (p < .05) were observed at the end of the follow-up. In multivariate logistic model, the interaction between UFR and IDH was notably associated with LVMI variation (OR = 1.37). After adjusting covariates, UFR was still an independent risk factor of LVMI variation (OR = 1.52) in IDH group. In subsequent analysis, we divided patients according to UFR 10 ml/h/kg. For IDH-prone patients, decreased EF, larger LADI, and LVMI (p < .05) were observed at the end of the study only in high-UFR group.

CONCLUSIONS

UFR and IDH have interactions on cardiac remodeling. High ultrafiltration rate induced IDH is a predictor for cardiac remodeling in long-term follow-up.

Multitargeted interventions to reduce dialysis-induced systemic stress

Hemodialysis (HD) is a life-sustaining therapy as well as an intermittent and repetitive stress condition for the patient. In ridding the blood of unwanted substances and excess fluid from the blood, the extracorporeal procedure simultaneously induces persistent physiological changes that adversely affect several organs. Dialysis patients experience this systemic stress condition usually thrice weekly and sometimes more frequently depending on the treatment schedule. Dialysis-induced systemic stress results from multifactorial components that include treatment schedule (i.e. modality, treatment time), hemodynamic management (i.e. ultrafiltration, weight loss), intensity of solute fluxes, osmotic and electrolytic shifts and interaction of blood with components of the extracorporeal circuit. Intradialytic morbidity (i.e. hypovolemia, intradialytic hypotension, hypoxia) is the clinical expression of this systemic stress that may act as a disease modifier, resulting in multiorgan injury and long-term morbidity. Thus, while lifesaving, HD exposes the patient to several systemic stressors, both hemodynamic and non-hemodynamic in origin. In addition, a combination of cardiocirculatory stress, greatly conditioned by the switch from hypervolemia to hypovolemia, hypoxemia and electrolyte changes may create pro-arrhythmogenic conditions. Moreover, contact of blood with components of the extracorporeal circuit directly activate circulating cells (i.e. macrophages-monocytes or platelets) and protein systems (i.e. coagulation, complement, contact phase kallikrein-kinin system), leading to induction of pro-inflammatory cytokines and resulting in chronic low-grade inflammation, further contributing to poor outcomes. The multifactorial, repetitive HD-induced stress that globally reduces tissue perfusion and oxygenation could have deleterious long-term consequences on the functionality of vital organs such as heart, brain, liver and kidney. In this article, we summarize the multisystemic pathophysiological consequences of the main circulatory stress factors. Strategies to mitigate their effects to provide more cardioprotective and personalized dialytic therapies are proposed to reduce the systemic burden of HD.

Soft Target Weight: Theory and Simulation of a Novel Haemodialysis Protocol Which Reduces Excessive Ultrafiltration

INTRODUCTION

Excessive ultrafiltration is associated with intra-dialytic symptoms, loss of residual function, and mortality in haemodialysis patients. A major contributor to excessive ultrafiltration is within-individual variation in pre-dialysis weight and the concept of achieving a fixed target weight by the end of each dialysis session. Haemodialysis protocols which allow variable post-dialysis weight have not been proposed.

METHODS

Weight variation was observed in haemodialysis patients and healthy controls to estimate the proportion of pre-dialysis weight variation which could be considered natural variation. These estimates were used to derive a novel protocol for setting ultrafiltration, which was evaluated by mathematical modelling.

RESULTS

Amongst 20 haemodialysis patients, mean (SD) pre-dialysis weight was 102.74 (0.94)% of target weight after a 2-day gap and 103.50 (0.94)% after a 3-day gap. Amongst 10 healthy individuals, mean (SD) daily weight was 100.0 (0.71)% of average weight. A 4-component model of pre-dialysis weight was derived using these estimates, in which the best estimate of pre-dialysis excess fluid is the midpoint of excess weight and average fluid gain, and used to propose a novel protocol for ultrafiltration setting. In simulations, the novel protocol reduced ultrafiltration variation by more than half (standard deviation 0.6 vs. 1.3% of target weight, p < 0.001), without increasing the variation in post-dialysis fluid excess. Excessive ultrafiltration rates (over 13 mL/h/kg) were far less frequent using this protocol (2.6% vs. 7.5% of sessions, p = 0.001).

CONCLUSION

Considering natural weight variation allows the development of a novel protocol for ultrafiltration in which target weight does not have to be achieved precisely: it is therefore a soft target. This protocol, which is predicted to substantially reduce excessive ultrafiltration variation, is a zero-cost intervention with the potential to improve symptoms and clinical outcome for haemodialysis patients.

Cost-Effectiveness of Home Hemodialysis With Bedside Portable Dialysis Machine "DIMI" in the United Arab Emirates

Background and objective

The incidence and prevalence of patients requiring renal replacement therapies (RRTs) are increasing worldwide and a large number of these patients die prematurely due to the unavailability of treatment. While in-center hemodialysis remains the most commonly practiced modality globally, more and more patients find it unsuitable due to their frail condition, difficulty in ambulation, and time lost in traveling, etc. Such patients find the self-administered or nurse-assisted home hemodialysis (NAHHD) more suitable. The costly and recurring nature of these therapies prompted us to evaluate and compare the cost-effectiveness aspect of these two treatment modalities. Thus, the aim of the study was to investigate if home hemodialysis (HHD) with a portable hemodialysis machine was cost-effective in comparison to in-center hemodialysis for patients of end-stage renal failure (ESRF) in the United Arab Emirates (UAE). This is the first study of its kind to be conducted in the UAE.

Methodology

The study topic was developed based on an informal inquiry from the health regulator of Abu Dhabi if HHD was cost-effective compared to in-center hemodialysis with an emphasis on a portable dialysis machine. No such head-to-head study performed in the UAE was available. Hence, a systematic review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) design was chosen as the investigative method. An outline of the study was drafted, and a literature search of Science of Web, PubMed, and Cochrane Evidence was performed using the keywords "Home Hemodialysis", "home-based Dialysis", "Cost-effectiveness of Dialysis", "Cost-effectiveness of renal replacement therapy", etc. A review of the article titles was performed to include the articles relevant to the cost of RRTs and the economic burden of ESRF. Full text and abstracts of those articles were retrieved, studied, and, the articles that were found not relevant were excluded. The remaining articles were studied and used in the evidence synthesis. DIMI was chosen to represent a standard type of recently developed portable dialysis machines.

Results

It was interesting to find out during the review that HHD and in-center hemodialysis had been developed simultaneously but the former had eventually fallen out of favor. The review revealed that HHD is not only as effective as in-center hemodialysis but is also associated with better survival benefits over the latter. Several studies have found it to be significantly cost-effective compared to in-center hemodialysis. Newer types of HHD machines make it easier for the patients or their family/caregivers to administer it safely and effectively at home and while traveling. They have regenerated interest in HHD and the Medicare administration in the USA has already decided to make use of it at a more frequent rate.

Conclusion

Based on the evidence in the available literature, HHD is cost-effective when compared to in-center hemodialysis in terms of survival benefits, quality of life (QoL) of patients, and monetary savings. Newer portable bedside dialysis machines provide better safety and have simplified the procedure of hemodialysis, making HHD more acceptable to patients and caregivers. We believe HHD should be the preferred modality of treatment instead of in-center hemodialysis, and that applies to UAE too.

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.

Assessment of cerebral oxygenation response to hemodialysis using near-infrared spectroscopy (NIRS): Challenges and solutions

To date, the clinical use of functional near-infrared spectroscopy (NIRS) to detect cerebral ischemia has been largely limited to surgical settings, where motion artifacts are minimal. In this study, we present novel techniques to address the challenges of using NIRS to monitor ambulatory patients with kidney disease during approximately eight hours of hemodialysis (HD) treatment. People with end-stage kidney disease who require HD are at higher risk for cognitive impairment and dementia than age-matched controls. Recent studies have suggested that HD-related declines in cerebral blood flow might explain some of the adverse outcomes of HD treatment. However, there are currently no established paradigms for monitoring cerebral perfusion in real-time during HD treatment. In this study, we used NIRS to assess cerebral hemodynamic responses among 95 prevalent HD patients during two consecutive HD treatments. We observed substantial signal attenuation in our predominantly Black patient cohort that required probe modifications. We also observed consistent motion artifacts that we addressed by developing a novel NIRS methodology, called the HD cerebral oxygen demand algorithm (HD-CODA), to identify episodes when cerebral oxygen demand might be outpacing supply during HD treatment. We then examined the association between a summary measure of time spent in cerebral deoxygenation, derived using the HD-CODA, and hemodynamic and treatment-related variables. We found that this summary measure was associated with intradialytic mean arterial pressure, heart rate, and volume removal. Future studies should use the HD-CODA to implement studies of real-time NIRS monitoring for incident dialysis patients, over longer time frames, and in other dialysis modalities.

Dialyzer surface area is a significant predictor of mortality in patients on hemodialysis: a 3-year nationwide cohort study

A target Kt/V of > 1.4 and use of a high-flux dialyzer are recommended for patients on hemodialysis. However, there is little information on the relationship between the dialyzer surface area and mortality in these patients. In this nationwide cohort study, we aimed to clarify this relationship by analyzing data from the Japanese Society for Dialysis Therapy for 2010–2013. We enrolled 234,638 patients on hemodialysis who were divided according to quartile for dialyzer surface area into the S group (small, < 1.5 m²), M group (medium, 1.5 m²), L group (large, 1.6 to < 2.0 m²), or XL group (extra-large, ≥ 2.0 m²). We assessed the association of each group with 3-year mortality using Cox proportional hazards models and performed propensity score matching analysis. By the end of 2013, a total of 53,836 patients on dialysis (22.9%) had died. There was a significant decrease in mortality with larger dialyzer surface areas. The hazard ratio (95% confidence interval) was significantly higher in the S group (1.15 [1.12–1.19], P < 0.0001) and significantly lower in the L group (0.89 [0.87–0.92] P < 0.0001) and XL group (0.75 [0.72–0.78], P < 0.0001) than in the M group as a reference after adjustment for all confounders. Findings were robust in several sensitivity analyses. Furthermore, the findings remained significant after propensity score matching. Hemodialysis using dialyzers, especially super high-flux dialyzers with a larger surface area might reduce mortality rates, and a surface area of ≥ 2.0 m² is superior, even with the same Kt/V.

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.

A maintenance hemodialysis mortality prediction model based on anomaly detection using longitudinal hemodialysis data

BACKGROUND

Most end-stage renal disease patients rely on hemodialysis (HD) to maintain their life, and they face a serious financial burden and high risk of mortality. Due to the current situation of the health care system in China, a large number of patients on HD are lost to follow-up, making the identification of patients with high mortality risks an intractable problem.

OBJECTIVE

This paper aims to propose a maintenance HD mortality prediction approach using longitudinal HD data under the situation of data imbalance caused by follow-up losses.

METHODS

A long short-term memory autoencoder (LSTM AE) based model is proposed to capture the physical condition changes of HD patients and distinguish between surviving and nonsurviving patients. The approach adopts anomaly detection theory, using only the surviving samples in the model training and identifying dead samples based on autoencoder reconstruction errors. The data are from a Chinese hospital electronic health record system between July 30, 2007, and August 25, 2016, and 36/72/108 continuous HD sessions were used to predict mortality within prediction windows of 90/180/365 days. Furthermore, the model performance is compared to that of logistic regression, support vector machine, random forest, LSTM classifier, isolation forest, and stacked autoencoder models.

RESULTS

Data for 1200 patients (survival: 1055, death: 145) were used to predict mortality during the next 90 days using 36 continuous HD sessions. The area under the PR curve for the LSTM AE was 0.57, the Recall_macro was 0.86, and the F1-score_macro was 0.87, outperforming the other models. Upon varying the observation window or prediction window length, LSTM AE continued to outperform the other models. According to the variable importance analysis, the dialysis session length was the feature that contributed the most to the prediction model.

CONCLUSIONS

The proposed approach was able to detect patients on maintenance HD with high mortality risk from an imbalanced dataset using anomaly detection theory and leveraging longitudinal HD data.

Toward an individualized determination of dialysis adequacy: a narrative review with special emphasis on incremental hemodialysis

INTRODUCTION

The search for the 'perfect' renal replacement therapy has been paralleled by the search for the perfect biomarkers for assessing dialysis adequacy. Three main families of markers have been assessed: small molecules (prototype: urea); middle molecules (prototype β2-microglobulin); comprehensive and nutritional markers (prototype of the simplified assessment, albumin levels; composite indexes as malnutrition-inflammation score). After an era of standardization of dialysis treatment, personalized dialysis schedules are increasingly proposed, challenging the dogma of thrice-weekly hemodialysis.

AREAS COVERED

In this review, we describe the advantages and limitations of the approaches mentioned above, focusing on the open questions regarding personalized schedules and incremental hemodialysis.

EXPERT OPINION

In the era of personalized dialysis, the assessment of dialysis adequacy should be likewise personalized, due to the limits of 'one size fits all' approaches. We have tried to summarize some of the relevant issues regarding the determination of dialysis adequacy, attempting to adapt them to an elderly, highly comorbidity population, which would probably benefit from tailor-made dialysis prescriptions. While no single biomarker allows precisely tailoring the dialysis dose, we suggest using a combination of clinical and biological markers to prescribe dialysis according to comorbidity, life expectancy, residual kidney function, and small and medium-size molecule depuration.

Clinical assessment of nutritional status using the modified quantified subjective global assessment and anthropometric and biochemical parameters in patients undergoing hemodialysis in Macao

OBJECTIVE

Malnutrition is widespread among patients undergoing hemodialysis and is linked to high morbidity and mortality rates. We evaluated the nutritional status and malnutrition markers in patients undergoing hemodialysis in Macao.

METHODS

We performed a cross-sectional analysis of 360 patients in a hemodialysis center. The modified quantitative subjective global assessment (MQSGA), anthropometric indices and related biochemical test data were used to evaluate nutritional status.

RESULTS

The sample's mean age was 63.47 ± 13.95 years. There were 210 well-nourished (58.3%), 139 mild-to-moderately malnourished (38.6%) and 11 severely malnourished (3.1%) patients. Older patients had a higher incidence of severe malnutrition, but there were no significant differences between diabetic and non-diabetic patients. Mid-arm circumference (MAC); mid-arm muscle circumference; body mass index; triceps skin fold thickness; serum albumin, creatinine and urea; and hemoglobin were all valid for assessing nutritional status. MAC and the serum albumin and creatinine concentrations significantly negatively correlated with MQSGA.

CONCLUSIONS

Malnutrition is commonplace in patients undergoing hemodialysis in Macao, but their nutritional status is not affected by diabetes. Serum creatinine, serum albumin and MAC, and especially pre-dialysis creatinine concentration, represent effective, readily available, and easily remembered screening measures of nutritional status for patients undergoing maintenance dialysis.

Association between facility-level adherence to phosphorus management guidelines and mortality in haemodialysis patients: a prospective cohort study

OBJECTIVES

To examine the association between facility-level adherence to phosphorus management guidelines and mortality among patients with haemodialysis, and to explore the facility-related factors associated with facility-level guideline adherence.

DESIGN

Prospective cohort study.

SETTING

The Dialysis Outcomes and Practice Pattern Study, which included 57 representative dialysis facilities in Japan between 2012 and 2015.

PARTICIPANTS

A total of 2054 adult patients who received maintenance haemodialysis were included. We defined exposure according to the following four categories, depending on whether facility-level target ranges of serum phosphorus concentration adhered to the Japanese clinical practice guidelines: adherence group (lower limit ≥3.5 mg/dL and upper limit ≤6.0 mg/dL), low-target group (lower limit <3.5 and upper limit ≤6.0), wide-target group (lower limit <3.5 and upper limit >6.0) and high-target group (lower limit ≥3.5 and upper limit >6.0).

PRIMARY OUTCOME MEASURE

The primary outcome was the patient all-cause mortality rate.

RESULTS

The mortality rate among the patients was 7.3 per 100 person-years; 27 facilities (47%) set targets according to the guidelines. HRs for mortality with reference to the adherence group were 1.04 (95% CI 0.76 to 1.43) in the low-target group, 1.11 (95% CI 0.68 to 1.81) in the wide-target group and 1.95 (95% CI 1.12 to 3.38) in the high-target group. Involvement of dieticians in dialysis treatment was associated with facility-level guideline adherence (OR 4.51; 95% CI 1.15 to 17.7).

CONCLUSIONS

A higher facility-level target range for phosphorus was associated with increased patient mortality. Among facilities that set the target according to the guidelines, dieticians tended to be involved in dialysis care. These findings suggest the importance of reviewing facilities' treatment policies in relation to updated guidelines and the need to work with relevant professionals.

Integrating Monitoring of Volume Status and Blood Volume-Controlled Ultrafiltration into Extracorporeal Kidney Replacement Therapy

Purpose

Volume management in hemodialysis (HD) requires the ability to assess volume status objectively and determine treatment strategies that achieve euvolemia without compromising hemodynamic stability. The aim of this study was to compare dialysis with and without blood volume-controlled ultrafiltration (UF) in combination with body composition monitoring, and to evaluate indicators for adequate dialysis (Kt/V), ultrafiltration volume, fluid status, and the occurrence of intradialytic morbid events (IME).

Patients and Methods

Patients undergoing hemodialysis or on-line hemodiafiltration with support of a blood volume monitor (BVM) - a feedback control device integrated into the 5008 and 6008 HD systems - were enrolled. Patients received treatment for four weeks using the 6008 CAREsystem and the BVM (6008+). Data on dialysis dose (Kt/V), UF volume and predialysis fluid status were documented. This data was also documented retrospectively for four weeks with (5008+) and without (5008-) the use of the BVM with the 5008 system. Comparisons were analyzed using linear mixed models.

Results

Twenty-four patients were enrolled. Kt/V was unaffected by blood volume-controlled UF (5008- vs 5008+: p=0.230) and was equally achieved with both HD systems (5008+ vs 6008+: p=0.922). The UF volume and fluid status achieved were comparable, independent of the use of UF control with BVM (5008- vs 5008+; UF volume: p=0.166; fluid overload: p=0.390) or the HD system (5008+ vs 6008+: UF volume: p=0.003; fluid overload: p=0.838), except for UF volume being higher in the 6008+ phase. IMEs occurred in less than 3% of treatments, with no difference between study phases.

Conclusion

This study demonstrates that a clinical approach to kidney replacement therapy that tracks volume status and manages intradialytic fluid removal by blood volume-controlled UF delivers adequate dialysis without compromising fluid removal. It maintains volume status and ensures low incidence of IMEs.

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.

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.

Intradialytic hypotension: is timing everything?

Intradialytic hypotension (IDH) is a major complication of hemodialysis, leading to myocardial stunning, cerebral hypoperfusion, gut ischemia, loss of residual kidney function, high symptom burden, and death. This study by Keane et al. provides new data on the incidence of IDH over well-defined time intervals during the hemodialysis treatment session, clinical parameters associated with the timing of IDH onset, and whether timing of IDH impacts survival in a nationally representative hemodialysis cohort.

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.

Serum total indoxyl sulfate and clinical outcomes in hemodialysis patients: results from the Japan Dialysis Outcomes and Practice Patterns Study

BACKGROUND

Uremic toxins are associated with various chronic kidney disease-related comorbidities. Indoxyl sulfate (IS), a protein-bound uremic toxin, reacts with vasculature, accelerating atherosclerosis and/or vascular calcification in animal models. Few studies have examined the relationship of IS with clinical outcomes in a large cohort of hemodialysis (HD) patients.

METHODS

We included 1170 HD patients from the Japan Dialysis Outcomes and Practice Patterns Study Phase 5 (2012-15). We evaluated the associations of serum total IS (tIS) levels with all-cause mortality and clinical outcomes including cardiovascular (CV)-, infectious- and malignancy-caused events using Cox regressions.

RESULTS

The median (interquartile range) serum tIS level at baseline was 31.6 μg/mL (22.6-42.0). Serum tIS level was positively associated with dialysis vintage. Median follow-up was 2.8 years (range: 0.01-2.9). We observed 174 deaths (14.9%; crude rate, 0.06/year). Serum tIS level was positively associated with all-cause mortality [adjusted hazard ratio per 10 μg/mL higher, 1.16; 95% confidence interval (CI) 1.04-1.28]. Association with cause-specific death or hospitalization events, per 10 μg/mL higher serum tIS level, was 1.18 (95% CI 1.04-1.34) for infectious events, 1.08 (95% CI 0.97-1.20) for CV events and 1.02 (95% CI 0.87-1.21) for malignancy events after adjusting for covariates including several nutritional markers.

CONCLUSIONS

In a large cohort study of HD patients, serum tIS level was positively associated with all-cause mortality and infectious events.

Anemia management for home dialysis including the new US public policy initiative

Patients with end-stage kidney disease (ESKD) requiring kidney replacement therapy are often treated in conventional dialysis centers at substantial cost and patient inconvenience. The recent United States Executive Order on Advancing American Kidney Health, in addition to focusing on ESKD prevention and reforming the kidney transplantation system, focuses on providing financial incentives to promote a shift toward home dialysis. In accordance with this order, a goal was set to have 80% of incident dialysis patients receiving home dialysis or a kidney transplant by 2025. Compared with conventional in-center therapy, home dialysis modalities, including both home hemodialysis and peritoneal dialysis, appear to offer equivalent or improved mortality, clinical outcomes, hospitalization rates, and quality of life in patients with ESKD in addition to greater convenience, flexibility, and cost-effectiveness. Treatment of anemia, a common complication of chronic kidney disease, may be easier to manage at home with a new class of agents, hypoxia-inducible factor-prolyl hydroxylase inhibitors, which are orally administered in contrast to the current standard of care of i.v. iron and/or erythropoiesis-stimulating agents. This review evaluates the clinical, quality-of-life, economic, and social aspects of dialysis modalities in patients with ESKD, including during the coronavirus disease 2019 pandemic; explores new therapeutics for the management of anemia in chronic kidney disease; and highlights how the proposed changes in Advancing American Kidney Health provide an opportunity to improve kidney health in the United States.

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.