Prognostic Value of Residual Urine Volume, GFR by 24-hour Urine Collection, and eGFR in Patients Receiving Dialysis

Early Anuria in Incident Peritoneal Dialysis Patients: Incidence, Risk Factors, and Associated Clinical Outcomes

Rationale & Objective

The development of anuria has been linked to worse clinical outcomes in patients undergoing peritoneal dialysis (PD). Our objective was to investigate the incidence, risk factors, and associated clinical outcomes of anuria within the first year after starting PD.

Study Design

Retrospective cohort study.

Setting & Participants

Patients who started continuous ambulatory peritoneal dialysis at our center between 2006 and 2020 were included and followed up until January 31, 2023.

Exposure

Age, sex, diabetes, temporary hemodialysis, angiotensin-converting enzyme inhibitors (ACEis) or angiotensin II receptor blockers (ARBs), diuretics, baseline urine volume, serum albumin, daily glucose exposure, peritonitis, and incremental PD.

Outcomes

The primary outcome was early anuria, defined as 24-hour urine volume ≤100 mL within the first year of PD initiation. Secondary outcomes included all-cause mortality, cardiovascular disease mortality, technique failure, and peritonitis.

Analytical Approach

Cox proportional hazards model.

Results

A total of 2,592 patients undergoing continuous ambulatory peritoneal dialysis aged 46.7 ± 14.9 years were recruited. Among them, 58.9% were male, and 24.0% had diabetes. Within the first year of PD therapy, 159 (6.13%) patients developed anuria, with a median duration of 7.53 (interquartile range, 3.93-10.0) months. Higher baseline urine volume (hazard ratio [HR], 0.93; 95% confidence interval [CI], 0.90-0.97), higher serum albumin (HR, 0.92; 95% CI, 0.88-0.95), having diabetes before PD (HR, 0.57; 95% CI, 0.35-0.92), and prescribed incremental PD (HR, 0.27; 95% CI, 0.14-0.51) were associated with a reduced risk for early anuria, whereas a higher level of daily glucose exposure (HR, 1.01; 95% CI, 1.00-1.01) was identified as a risk factor for early anuria. Subgroup analyses showed that using ACEis or ARBs was linked to a lower risk of early anuria (HR, 0.25; 95% CI, 0.09-0.69) in diabetic patients. Treating early anuria as a time-dependent covariate, early anuria was associated with a higher risk for all-cause mortality (HR, 1.69; 95% CI, 1.23-2.32) and technique failure (HR, 1.43; 95% CI, 1.00-2.04) after adjusting for confounding factors.

Limitations

Single-center and observational study.

Conclusions

Among PD patients at a single center in China, early anuria was relatively uncommon but associated with an increased risk of mortality and PD technique failure. Incremental PD, higher baseline urine output and serum albumin, and lower daily glucose exposure were associated with a lower risk of early anuria. Clinical trials are needed to evaluate the optimal PD techniques to preserve residual kidney function and maximaze outcomes.

Residual Kidney Function in Hemodialysis: Its Importance and Contribution to Improved Patient Outcomes

Individuals afflicted with advanced kidney dysfunction who require dialysis for medical management exhibit different degrees of native kidney function, called residual kidney function (RKF), ranging from nil to appreciable levels. The primary focus of this manuscript is to delve into the concept of RKF, a pivotal yet under-represented topic in nephrology. To begin, we unpack the definition and intrinsic nature of RKF. We then juxtapose the efficiency of RKF against that of hemodialysis in preserving homeostatic equilibrium and facilitating physiological functions. Given the complex interplay of RKF and overall patient health, we shed light on the extent of its influence on patient outcomes, particularly in those living with advanced kidney dysfunction and on dialysis. This manuscript subsequently presents methodologies and measures to assess RKF, concluding with the potential benefits of targeted interventions aimed at preserving RKF.

Incremental dialysis: review of the literature with pediatric perspective

Drivers towards initiation of kidney replacement therapy in advanced chronic kidney disease include metabolic and fluid derangements, growth, and nutritional status with focus on health optimization. Once initiated, prescription of dialysis is often uniform despite variability in patient characteristics and etiology of kidney failure. Preservation of residual kidney function has been associated with improved outcomes in patients with advanced chronic kidney disease on dialysis. Incremental dialysis is the approach of reducing the dialysis dose by reduction in treatment time, days, or efficiency of clearance. Incremental dialysis has been described in adults at initiation of kidney replacement therapy, to better preserve residual kidney function and meet the individual needs of the patient. Consideration of incremental dialysis in pediatrics may be reasonable in a subset of children with continued emphasis on promotion of growth and development.

Incremental peritoneal dialysis and survival outcomes: a propensity-matched cohort study

BACKGROUND

The advantages of an incremental dialysis start are not fully clear. We aimed to evaluate the association of incremental initiation of peritoneal dialysis with mortality.

METHODS

Incident peritoneal dialysis patients with a catheter placed at our hospital between 2008 and 2017 were included. All patients were followed up until December 31, 2019. Patients were categorized into different groups according to the initial daily dialysis exchanges, and were matched at a ratio of 1:2 with propensity score matching. Multiple variables including age, sex, residual kidney function, urine volume, hemoglobin, serum albumin and other important variables were included for the matching. Primary outcomes were all-cause and cardiovascular mortality.

RESULTS

A total of 1315 patients with a mean age of 45.9 years were enrolled. The mean glomerular filtration rate was 4.32 ml/min/1.73 m2 at start of dialysis. Two hundred eighty-five patients in the incremental group and 502 in the full dose group were matched for age, sex, residual kidney function, urine volume, hemoglobin, serum albumin and other important variables. Patient survival and cardiovascular event-free survival were similar between the two groups. However, during the first 6 years of peritoneal dialysis, patients in the incremental group had better survival (P = 0.011) and cardiovascular event-free survival (P = 0.044) than the full dose group, while such advantages disappeared when dialysis vintage became longer. Further analysis showed that the incremental group (vs full dose dialysis) had a 39% lower risk (95% CI 0.42-0.90, P = 0.012) of all-cause mortality and a 41% decreased risk (95% CI 0.35-0.99, P = 0.047) of cardiovascular mortality during the first 6 years of dialysis. Additionally, the cumulative hazard for anuria was significantly lower in the incremental group versus the full dose group (P = 0.006).

CONCLUSIONS

Our study shows a time-related survival advantage for incremental peritoneal dialysis patients, suggesting that an incremental regimen for starting peritoneal dialysis is feasible and is not associated with worse outcomes. Graphical Abstract presenting schematically the measurements of the solvation response function by processing the relevant streak camera images and the time-correlated photon counting (TCSPC) data and appropriately combining them together.

SGLT2 Inhibitors: The Sweet Success for Kidneys

Sodium-glucose cotransporter-2 inhibitors (SGLT2 inhibitors) were originally developed as antidiabetic agents, with cardiovascular (CV) outcome trials demonstrating improved CV outcomes in patients with type 2 diabetes mellitus (T2D). Secondary analyses of CV outcome trials and later dedicated kidney outcome trials consistently reported improved kidney-related outcomes independent of T2D status and across a range of kidney function and albuminuria. Importantly, SGLT2 inhibitors are generally safe and well tolerated, with clinical trials and real-world analyses demonstrating a decrease in the risk of acute kidney injury. The kidney protective effects of SGLT2 inhibitors generally extend across different members of the class, possibly on the basis of hemodynamic, metabolic, anti-inflammatory, and antifibrotic mechanisms. In this review, we summarize the effects of SGLT2 inhibitors on kidney outcomes in diverse patient populations.

Late Dialysis Modality Education Could Negatively Predict Peritoneal Dialysis Selection

Patients with end-stage renal disease are less likely to choose peritoneal dialysis (PD) as renal replacement therapy (RRT). The reasons for this biased selection are still poorly understood. In this study, we evaluated the effect of the timing of RRT education on PD selection. This single-center retrospective observational study included patients who initiated maintenance dialysis at our hospital between April 2014 and July 2021. A logistic regression analysis was performed to investigate the association of RRT education timing with PD selection. Among the 355 participants (median age [IQR] 70 (59−79) years; 28.7% female), 53 patients (14.9%) and 302 patients (85.1%) selected PD and hemodialysis, respectively. Multivariate analysis demonstrated that high estimated glomerular filtration (eGFR) at RRT education positively predicted PD selection (p < 0.05), whereas old age (p < 0.01) and high Charlson comorbidity index (p < 0.05) were negative predictors of PD selection. Female sex (p = 0.44), welfare public assistance (p = 0.78), living alone (p = 0.25), high geriatric nutritional risk index (p = 0.10) and high eGFR at first visit to the nephrology department (p = 0.83) were not significantly associated with PD selection. Late RRT education could increase the biased selection of dialysis modality.

Outcomes of incident patients treated with incremental haemodialysis as compared with standard haemodialysis and peritoneal dialysis

BACKGROUND

Residual kidney function is considered better preserved with incremental haemodialysis (I-HD) or peritoneal dialysis (PD) as compared with conventional thrice-weekly HD (TW-HD) and is associated with improved survival. We aimed to describe outcomes of patients initiating dialysis with I-HD, TW-HD or PD.

METHODS

We conducted a retrospective analysis of a prospectively assembled cohort in a single university centre including all adults initiating dialysis from January 2013 to December 2020. Primary and secondary endpoints were overall survival and hospitalization days at 1 year, respectively.

RESULTS

We included 313 patients with 234 starting on HD (166 TW-HD and 68 I-HD) and 79 on PD. At the end of the study, 10 were still on I-HD while 45 transitioned to TW-HD after a mean duration of 9.8 ± 9.1 months. Patients who stayed on I-HD were less frequently diabetics (P = .007). Mean follow-up was 33.1 ± 30.8 months during which 124 (39.6%) patients died. Compared with patients on TW-HD, those on I-HD had improved survival (hazard ratio 0.49, 95% confidence interval 0.26-0.93, P = .029), while those on PD had similar survival. Initial kidney replacement therapy modality was not significantly associated with hospitalization days at 1 year.

CONCLUSIONS

I-HD is suitable for selected patients starting dialysis and can be maintained for a significant amount of time before transition to TW-HD, with diabetes being a risk factor. Although hospitalization days at 1 year are similar, initiation with I-HD is associated with improved survival as compared with TW-HD or PD. Results of randomized controlled trials are awaited prior to large-scale implementation of I-HD programmes.

Peritoneal Dialysis for Potential Kidney Transplant Recipients: Pride or Prejudice?

Kidney transplantation (KT) is recognized as the gold-standard of treatment for patients with end-stage renal disease. Additionally, it has been demonstrated that receiving a pre-emptive KT ensures the best recipient and graft survivals. However, due to an overwhelming discrepancy between the organs available and the patients on the transplant waiting list, the vast majority of transplant candidates require prolonged periods of dialysis before being transplanted. For many years, peritoneal dialysis (PD) and hemodialysis (HD) have been considered competitive renal replacement therapies (RRT). This dualistic vision has recently been questioned by evidence suggesting that an individualized and flexible approach may be more appropriate. In fact, tailored and cleverly planned changes between different RRT modalities, according to the patient’s needs and characteristics, are often needed in order to achieve the best results. While home HD is still under scrutiny in this particular setting, current data seems to favor the use of PD over in-center HD in patients awaiting a KT. In this specific population, the demonstrated advantages of PD are superior quality of life, longer preservation of residual renal function, lower incidence of delayed graft function, better recipient survival, and reduced cost.

Does delivering more dialysis improve clinical outcomes? What randomized controlled trials have shown

Some randomized controlled trials (RCTs) have sought to determine whether different dialysis techniques, dialysis doses and frequencies of treatment are able to improve clinical outcomes in end-stage kidney disease (ESKD). Virtually all of these RCTs were enacted on the premise that 'more' haemodialysis might improve clinical outcomes compared to 'conventional' haemodialysis. Aim of the present narrative review was to analyse these landmark RCTs by posing the following question: were their intervention strategies (i.e., earlier dialysis start, higher haemodialysis dose, intensive haemodialysis, increase in convective transport, starting haemodialysis with three sessions per week) able to improve clinical outcomes? The answer is no. There are at least two main reasons why many RCTs have failed to demonstrate the expected benefits thus far: (1) in general, RCTs included relatively small cohorts and short follow-ups, thus producing low event rates and limited statistical power; (2) the designs of these studies did not take into account that ESKD does not result from a single disease entity: it is a collection of different diseases and subtypes of kidney dysfunction. Patients with advanced kidney failure requiring dialysis treatment differ on a multitude of levels including residual kidney function, biochemical parameters (e.g., acid base balance, serum electrolytes, mineral and bone disorder), and volume overload. In conclusion, the different intervention strategies of the RCTs herein reviewed were not able to improve clinical outcomes of ESKD patients. Higher quality studies are needed to guide patients and clinicians in the decision-making process. Future RCTs should account for the heterogeneity of patients when considering inclusion/exclusion criteria and study design, and should a priori consider subgroup analyses to highlight specific subgroups that can benefit most from a particular intervention.

The failing kidney allograft: A review and recommendations for the care and management of a complex group of patients

The return to dialysis after allograft failure is associated with increased morbidity and mortality. This transition is made more complex by the rising numbers of patients who seek repeat transplantation and therefore may have indications for remaining on low levels of immunosuppression, despite the potential increased morbidity. Management strategies vary across providers, driven by limited data on how to transition off immunosuppression as the allograft fails and a paucity of randomized controlled trials to support one approach over another. In this review, we summarize the current data available for management and care of the failing allograft. Additionally, we discuss a suggested plan for immunosuppression weaning based upon the availability of re-transplantation and residual allograft function. We propose a shared-care model in which there is improved coordination between transplant providers and general nephrologists so that immunosuppression management and preparation for renal replacement therapy and/or repeat transplantation can be conducted with the goal of improved outcomes and decreased morbidity in this vulnerable patient group.

Residual Urine Output and Mortality in a Prospective Hemodialysis Cohort

Introduction

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

Methods

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

Results

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

Conclusion

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

Prediction of the Mortality Risk in Peritoneal Dialysis Patients using Machine Learning Models: A Nation-wide Prospective Cohort in Korea

Herein, we aim to assess mortality risk prediction in peritoneal dialysis patients using machine-learning algorithms for proper prognosis prediction. A total of 1,730 peritoneal dialysis patients in the CRC for ESRD prospective cohort from 2008 to 2014 were enrolled in this study. Classification algorithms were used for prediction of N-year mortality including neural network. The survival hazard ratio was presented by machine-learning algorithms using survival statistics and was compared to conventional algorithms. A survival-tree algorithm presented the most accurate prediction model and outperformed a conventional method such as Cox regression (concordance index 0.769 vs 0.745). Among various survival decision-tree models, the modified Charlson Comorbidity index (mCCI) was selected as the best predictor of mortality. If peritoneal dialysis patients with high mCCI (>4) were aged ≥70.5 years old, the survival hazard ratio was predicted as 4.61 compared to the overall study population. Among the various algorithm using longitudinal data, the AUC value of logistic regression was augmented at 0.804. In addition, the deep neural network significantly improved performance to 0.841. We propose machine learning-based final model, mCCI and age were interrelated as notable risk factors for mortality in Korean peritoneal dialysis patients.

Variations in Circulating Active MMP-9 Levels During Renal Replacement Therapy

Renal replacement therapy (RRT) is complicated by a chronic state of inflammation and a high mortality risk. However, different RRT modalities can have a selective impact on markers of inflammation and oxidative stress. We evaluated the levels of active matrix metalloproteinase (MMP)-9 in patients undergoing two types of dialysis (high-flux dialysis (HFD) and on-line hemodiafiltration (OL-HDF)) and in kidney transplantation (KT) recipients. Active MMP-9 was measured by zymography and ELISA before (pre-) and after (post-) one dialysis session, and at baseline and follow-up (7 and 14 days, and 1, 3, 6, and 12 months) after KT. Active MMP-9 decreased post-dialysis only in HFD patients, while the levels in OL-HDF patients were already lower before dialysis. Active MMP-9 increased at 7 and 14 days post-KT and was restored to baseline levels three months post-KT, coinciding with an improvement in renal function and plasma creatinine. Active MMP-9 correlated with pulse pressure as an indicator of arterial stiffness both in dialysis patients and KT recipients. In conclusion, active MMP-9 is better controlled in OL-HDF than in HFD and is restored to baseline levels along with stabilization of renal parameters after KT. Active MMP-9 might act as a biomarker of arterial stiffness in RRT.

Renin Angiotensin Aldosterone System Blockades Does Not Protect Residual Renal Function in Patients with Hemodialysis at 1 Year After Dialysis Initiation: A Prospective Observational Cohort Study

The beneficial effects of renin angiotensin aldosterone system (RAAS) blockade on residual renal function (RRF) in patients who have just initiated hemodialysis (HD) have been inconclusive. In this study, 935 patients with incident HD from a nationwide prospective observational cohort in Korea were included for analysis. The primary outcome showed that RRF as demonstrated by urine volume changes over 0, 3, and 12 months differed between the RAAS blockade and control groups. Mixed-effects linear regression was used to compare RRF between the groups. Patients in the RAAS group had a greater proportion of higher urine volume at study enrollment compared to the control group, but there was no difference in baseline characteristics, heart function, and dialysis-related indices. After adjusting for confounding factors, the RAAS group did not provide a significant benefit to RRF in a mixed-effects linear regression (p = 0.51). Male gender, high Charlson comorbidity index, diuretic use, and high weekly ultrafiltration volume were associated with faster decline in RRF. The RAAS group failed to provide a protective effect for the development of anuria 1 year after initiating dialysis based on the multivariate logistic regression (OR 0.73 95% CI 0.25-2.13, p = 0.57). In Korean patients with incident HD, RAAS blockade did not provide a protective effect for RRF after 1 year. Further research is needed to clarify the optimal treatment for preserving RRF in HD patients.

Estimating Residual Native Kidney Urea Clearance in Hemodialysis Patients with and without 24-Hour Urine Volume

Rationale & Objective

Quantification of residual native kidney function is rarely performed in patients receiving hemodialysis. Methods of estimating residual kidney urea clearance that use commonly available laboratory and clinical data, with or without urine volume information, may be useful tools.

Study Design

Retrospective, predictive modeling and model validation.

Setting & Participants

Initial timed urine collections in 604 incident in-center hemodialysis patients on thrice-weekly treatments from a single academic center in which residual kidney urea clearance is measured in usual care.

Predictors

Models using a combination of serum creatinine and urea levels, age, weight, height, sex, race, fluid weight gains, and with and without 24-hour urine volume.

Outcomes

Residual kidney urea clearance.

Analytic Approach

Generalized linear model was used for model development for residual kidney urea clearance using the first urine collection in 604 patients, as both a continuous and binary outcome (for >2.5 mL/min). Model validation was done by bootstrap resampling of the development cohort and with 1,093 follow-up measurements.

Results

Urine volume alone was the strongest predictor of residual kidney urea clearance. The model that included 24-hour urine volume with common clinical data had high diagnostic accuracy for residual kidney urea clearance > 2.5 mL/min (area under the curve, 0.91 in both development and bootstrap validation) and R² of 0.56 with outcome as a continuous residual kidney urea clearance value. Our model that did not use urine volume performed less well (eg, area under the curve, 0.75). Analyses of follow-up urine collections in these same participants yielded comparable or improved performance.

Limitations

Data were retrospective from a single center, no external validation, not validated in 2- or 4-times-weekly hemodialysis patients.

Conclusions

Estimation equations for residual kidney urea clearance that use commonly available data in dialysis clinics, with and without urine volume, may be useful tools for evaluation of hemodialysis patients who still have residual kidney function for individualization of dialysis prescriptions.

Hypomagnesemia is not an independent risk factor for mortality in Japanese maintenance hemodialysis patients

PURPOSE

It is unclear whether hypomagnesemia is an independent risk factor or innocent bystander for mortality in maintenance hemodialysis (MHD) patients. Thus, we studied associations between hypomagnesemia and all-cause as well as cardiovascular (CV) mortality in MHD patients.

METHODS

Baseline clinical characteristics and coronary artery calcium score (CACS) of 353 Japanese MHD patients were reviewed. Three-year survival rate and mortality risk factors were assessed.

RESULTS

Median (interquartile range) age, dialysis vintage, serum magnesium (Mg), serum albumin and CACS of the subjects were 68 (60-78) years, 75 (32-151) months, 2.4 (2.2-2.7) mg/dl, 3.6 (3.3-3.8) g/dl, and 1181 (278-3190), respectively. During the 3-year period, 91 patients died. Kaplan-Meier overall 3-year survival rates were 59.0% in in patients with Mg < 2.4 mg/dl (n = 136) and 82.3% in patients with Mg ≥ 2.4 mg/dl (n = 217), (P < 0.0001). In Cox regression models not incorporating serum albumin, Mg < 2.4 mg/dl was significantly associated with 3-year all-cause death, independent of age, dialysis vintage, average ultrafiltration, Log (CACS + 1), warfarin use, serum potassium, high-sensitivity C-reactive protein (hsCRP), phosphate, uric acid, and intact parathyroid hormone [Hazard ratio (HR) 95% confidence interval (CI): 2.82 (1.31-6.29), P = 0.0078], and CV death, independent of age, dialysis vintage, Log (CACS + 1), warfarin use, serum hsCRP, and uric acid [HR (95% CI): 4.47 (1.45-16.76), P = 0.0086]. Nevertheless, associations of Mg < 2.4 mg/dl with all-cause and CV mortality were all absent in models that included serum albumin.

CONCLUSIONS

Hypomagnesemia is not an independent risk factor for mortality but is associated with malnutrition in MHD patients.

Patient-reported advantages and disadvantages of peritoneal dialysis: results from the PDOPPS

BACKGROUND

Patient-reported measures are increasingly recognized as important predictors of clinical outcomes in peritoneal dialysis (PD). We sought to understand associations between patient-reported perceptions of the advantages and disadvantages of PD and clinical outcomes.

METHODS

In this cohort study, 2760 PD patients in the Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS) completed a questionnaire on their PD experience, between 2014 and 2017. In this questionnaire, PDOPPS patients rated 17 aspects of their PD experience on a 5-category ordinal scale, with responses scored from - 2 (major disadvantage) to + 2 (major advantage). An advantage/disadvantage score (ADS) was computed for each patient by averaging their response scores. The ADS, along with each of these 17 aspects, were used as exposures. Outcomes included mortality, transition to hemodialysis (HD), patient-reported quality of life (QOL), and depression. Cox regression was used to estimate associations between ADS and mortality, transition to HD, and a composite of the two. Logistic regression with generalized estimating equations was used to estimate cross-sectional associations of ADS with QOL and depression.

RESULTS

While 7% of PD patients had an ADS < 0 (negative perception of PD), 59% had an ADS between 0 and < 1 (positive perception), and 34% had an ADS ≥1 (very positive perception). Minimal association was observed between mortality and the ADS. Compared with a very positive perception, patients with a negative perception had a higher transition rate to HD (hazard ratio [HR] = 1.67; 95% confidence interval [CI]: 1.21, 2.30). Among individual items, "space taken up by PD supplies" was commonly rated as a disadvantage and had the strongest association with transition to HD (HR = 1.28; 95% CI 1.07, 1.53). Lower ADS was strongly associated with worse QOL rating and greater depressive symptoms.

CONCLUSIONS

Although patients reported a generally favorable perception of PD, patient-reported disadvantages were associated with transition to HD, lower QOL, and depression. Strategies addressing these disadvantages, in particular reducing solution storage space, may improve patient outcomes and the experience of PD.

Effect of Renin-Angiotensin-Aldosterone System Blockade on Outcomes in Patients With ESRD: A Prospective Cohort Study in Korea

Introduction

Conflicting results still exist regarding the benefit of renin-angiotensin-aldosterone system (RAAS) blockade on clinical outcomes in dialysis patients. The aim of this study was to evaluate the effects of RAAS blockade on survival in Korean patients with end-stage renal disease (ESRD).

Methods

Our analysis was based on the data of 5223 patients enrolled from the Clinical Research Center for ESRD, a nationwide prospective observational cohort. Multivariate Cox regression was applied for risk factor analysis with the cumulative duration of RAAS blockade use as time-varying covariate. The risks for mortality from all causes and major cardiovascular event-free survival were estimated.

Results

Compared to the control group, patients in the RAAS group were younger but had a higher proportion of diabetes mellitus, had higher systolic blood pressure, required a greater number of prescribed antihypertensive drugs, and had a longer dialysis duration. On multivariate time-varying Cox regression analysis, the RAAS group with cumulative duration of >90 days was significantly associated with a lower risk of mortality from all causes after adjustment for confounding (hazard ratio [HR] = 0.45, 95% confidence interval [CI] = 0.35-0.58, P < 0.0001). Major cardiovascular event-free survival was also better for the RAAS group than for the control group on multivariate analysis (HR = 0.27, 95% CI = 0.20-0.37, P < 0.0001), considering the cumulative duration of RAAS blockade use.

Conclusion

In Korean patients with ESRD, we reported a specific benefit of RAAS blockade in improving overall survival after adjustment for confounding factors from real-world data.

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

Background

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

Methods

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

Results

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

Conclusions

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

Trial registration

UMIN000027555, May 30, 2017 (retrospectively registered).

Ultrafiltration rate in conventional hemodialysis: Where are the limits and what are the consequences?

BACKGROUND

Ultrafiltration rate (UFR) has attracted attention as a modifiable aspect of volume management.

OBJECTIVE

The objective of this review is to summarize the evidence that links UFR to patient outcomes and discuss UFR cut-offs proposed, and discuss possible consequences of adapting UFR as a quality metric.

RESULTS

Higher UFRs has been associated with younger age, longer dialysis vintage, greater prevalence of comorbidities, higher Kt/V, lower weight, greater interdialytic weight gain, lower residual renal function, and shorter treatment times. Many of the characteristics associated with high UFRs have also been independently associated with poor patient outcomes. Four observational studies have assessed the association between UFR and patient mortality. All of them reported an association between higher UFR and greater patient mortality, though the studies differed in their definition of UFR, follow-up, and adjustment for confounding. Evidence for the association between higher UFR and potential mediations of the mortality association, such as interdialytic hypotension, cardiac remodeling, and cardiovascular events was less consistent. There was a graded association between higher UFRs and all-cause mortality; no definitive cut-off for acceptable UFR can be established based on the current evidence. Targeting UFR in isolation might result in volume expansion and worsening patient outcomes. Residual confounding likely contributed to the findings of the observational studies. No randomized controlled trials addressed the questions.

CONCLUSION

Evidence supporting UFR limits is weak and confounded. Randomized controlled trials are needed before UFR can be used as a quality of care indicator.

Estimating of Residual Kidney Function by Multi-Frequency Bioelectrical Impedance Analysis in Hemodialysis Patients Without Urine Collection

BACKGROUND/AIMS

Residual kidney function (RKF) is a pivotal predictor of better clinical outcomes in maintenance hemodialysis (MHD) patients. So far there has been no attempt to use bioimpedance analysis (BIA) measurements to calculate residual glomerular filtration rate (GFR) in dialysis population. We hypothesized that performing of multi-frequency BIA at the beginning and end of hemodialysis session can enable us to predict the measured residual GFR in MHD patients. Thus our aim was to develop and validate a new RKF prediction equation using multi-frequency BIA in MHD patients.

METHODS

It was diagnostic test evaluation study in a prospective cohort. Participants (n=88; mean age, 66.3±13.2 years, 59.1% males) were recruited from a single hemodialysis center. A new equation (eGFRBIA) to predict RKF, utilizing BIA measurements performed pre- and post-dialysis, was generated and cross-validated by the leave-one-out procedure. GFR estimated as the mean of urea and creatinine clearance (mGFR) using urine collections during entire interdialytic period.

RESULTS

A prediction equation for mGFR that includes both pre- and post-dialysis BIA measurements provided a better estimate than either pre- or post-dialysis measurements alone. Mean bias between predicted and measured GFR was -0.12 ml/min. Passing and Bablok regression showed no bias and no significant deviation in linearity. Concordance correlation coefficient indicated good agreement between the eGFRBIA and mGFR (0.75, P<0.001). Using cut-off predicted mGFR levels >2 ml/min/1.73 m2 yielded an area under curve of 0.96, sensitivity 85%, and specificity 89% in predicting mGFR. The κ scores for intraobserver reproducibility were consistent with substantial agreement between first and second estimation of RKF according to eGFRBIA (weighted κ was 0.60 [0.37-0.83]).

CONCLUSION

We present a valid and clinically obtainable method to predict RKF in MHD patients. This method, which uses BIA, may prove as accurate, convenient and easily reproducible while it is operator independent.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

DISCUSSION

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

Allocating scarce medical resources during armed conflict: ethical issues

We describe ethical issues arising in the allocation of civilian medical resources during armed conflict. Three features are significant in the context of allocating scarce resources in armed conflicts: the distinction between continuous and binary medical resources; the risks of armed conflict itself, and the impact of cultural differences on cases of armed conflict. We use these factors to elicit a modified principle for allocating medical resources during armed conflict, using hemodialysis for patients with end-stage renal disease as a case study.