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

Predictors of Change in Left-Ventricular Structure and Function in a Trial of Extended Hours Hemodialysis

BACKGROUND

Myocardial pathology is common in patients undergoing hemodialysis. To explore the effects of differing aspects of dialysis treatment on its evolution, we examined the impact of change in markers of volume status, hemodynamics and solute clearance on left ventricular (LV) parameters in a randomized trial of extended hours dialysis.

METHODS AND RESULTS

A Clinical Trial of IntensiVE (ACTIVE) Dialysis randomized 200 patients undergoing hemodialysis to extended dialysis hours (≥ 24 hours/week) or standard hours (12-18 hours/week) for 12 months. In a prespecified substudy, 95 participants underwent cardiac magnetic resonance imaging (CMR) at baseline and at the study's end. Generalized linear regression was used to model the relationship between changes in LV parameters and markers of volume status (normalized ultrafiltration rate and total weekly interdialytic weight gain), hemodynamic changes (systolic and diastolic blood pressure) and solute control (urea clearance, dialysis hours and phosphate). Randomization to extended hours dialysis was not associated with change in any CMR parameter. Reduction in ultrafiltration rate was associated with reduction in LV mass index (P = 0.049) and improved ejection fraction (P = 0.024); reduction in systolic blood pressure was also associated with improvement in ejection fraction (P = 0.045); reduction in interdialytic weight gain was associated with reduced stroke volume (P = 0.038). There were no associations between change in urea clearance, phosphate or total hours per week and CMR parameters.

CONCLUSIONS

Reduction in ultrafiltration rate and blood pressure are associated with improved myocardial parameters in hemodialysis recipients independently of solute clearance or dialysis time. These findings underscore the importance of fluid status and related parameters as potential treatment targets in this population.

Seasonal and Secular Trends of Cardiovascular, Nutritional, and Inflammatory Markers in Patients on Hemodialysis

BACKGROUND

All life on earth has adapted to the effects of changing seasons. The general and ESKD populations exhibit seasonal rhythms in physiology and outcomes. The ESKD population also shows secular trends over calendar time that can convolute the influences of seasonal variations. We conducted an analysis that simultaneously considered both seasonality and calendar time to isolate these trends for cardiovascular, nutrition, and inflammation markers.

METHODS

We used data from adult patients on hemodialysis (HD) in the United States from 2010 through 2014. An additive model accounted for variations over both calendar time and time on dialysis. Calendar time trends were decomposed into seasonal and secular trends. Bootstrap procedures and likelihood ratio methods tested if seasonal and secular variations exist.

RESULTS

We analyzed data from 354,176 patients on HD at 2436 clinics. Patients were 59±15 years old, 57% were men, and 61% had diabetes. Isolated average secular trends showed decreases in pre-HD systolic BP (pre-SBP) of 2.6 mm Hg (95% CI, 2.4 to 2.8) and interdialytic weight gain (IDWG) of 0.35 kg (95% CI, 0.33 to 0.36) yet increases in post-HD weight of 2.76 kg (95% CI, 2.58 to 2.97). We found independent seasonal variations of 3.3 mm Hg (95% CI, 3.1 to 3.5) for pre-SBP, 0.19 kg (95% CI, 0.17 to 0.20) for IDWG, and 0.62 kg (95% CI, 0.46 to 0.79) for post-HD weight as well as 0.12 L (95% CI, 0.11 to 0.14) for ultrafiltration volume, 0.41 ml/kg per hour (95% CI, 0.37 to 0.45) for ultrafiltration rates, and 3.30 (95% CI, 2.90 to 3.77) hospital days per patient year, which were higher in winter versus summer.

CONCLUSIONS

Patients on HD show marked seasonal variability of key indicators. Secular trends indicate decreasing BP and IDWG and increasing post-HD weight. These methods will be of importance for independently determining seasonal and secular trends in future assessments of population health.

Net Ultrafiltration Prescription and Practice Among Critically Ill Patients Receiving Renal Replacement Therapy: A Multinational Survey of Critical Care Practitioners

OBJECTIVES

To assess the attitudes of practitioners with respect to net ultrafiltration prescription and practice among critically ill patients with acute kidney injury treated with renal replacement therapy.

DESIGN

Multinational internet-assisted survey.

SETTING

Critical care practitioners involved with 14 societies in 80 countries.

SUBJECTS

Intervention: MEASUREMENT AND MAIN RESULTS:: Of 2,567 practitioners who initiated the survey, 1,569 (61.1%) completed the survey. Most practitioners were intensivists (72.7%) with a median duration of 13.2 years of practice (interquartile range, 7.2-22.0 yr). Two third of practitioners (71.0%; regional range, 55.0-95.5%) reported using continuous renal replacement therapy with a net ultrafiltration rate prescription of median 80.0 mL/hr (interquartile range, 49.0-111.0 mL/hr) for hemodynamically unstable and a maximal rate of 299.0 mL/hr (interquartile range, 200.0-365.0 mL/hr) for hemodynamically stable patients, with regional variation. Only a third of practitioners (31.5%; range, 13.7-47.8%) assessed hourly net fluid balance during continuous renal replacement therapy. Hemodynamic instability was reported in 20% (range, 20-38%) of patients and practitioners decreased the rate of fluid removal (70.3%); started or increased the dose of a vasopressor (51.5%); completely stopped fluid removal (35.8%); and administered a fluid bolus (31.6%), with significant regional variation. Compared with physicians, nurses were most likely to report patient intolerance to net ultrafiltration (73.4% vs 81.3%; p = 0.002), frequent interruptions (40.4% vs 54.5%; p < 0.001), and unavailability of trained staff (11.9% vs 15.6%; p = 0.04), whereas physicians reported unavailability of dialysis machines (14.3% vs 6.1%; p < 0.001) and costs associated with treatment as barriers (12.1% vs 3.0%; p < 0.001) with significant regional variation.

CONCLUSIONS

Our study provides new knowledge about the presence and extent of international practice variation in net ultrafiltration. We also identified barriers and specific targets for quality improvement initiatives. Our data reflect the need for evidence-based practice guidelines for net ultrafiltration.

Solute and Volume Dosing during Kidney Replacement Therapy in Critically Ill Patients with Acute Kidney Injury

Among critically ill patients with severe acute kidney injury either continuous kidney replacement therapy (CKRT) or intermittent hemodialysis (IHD) can be performed to provide optimal solute and volume control. The modality of KRT should be chosen based on the needs of the patient, hemodynamic status, clinician expertise, and resource available under a particular setting and consideration of costs. Evidence from high-quality randomized trials suggests that an effluent flow rate of 25 mL/kg/hour per day using CKRT and Kt/V of 1.3 per session of IHD provide optimal solute control. For volume dosing, the net ultrafiltration (UF_NET) rate should be prescribed based on patient body weight in milliliters per kilogram per hour, with close monitoring of patient hemodynamics and fluid balance. Emerging evidence from observational studies suggests a “J”-shaped association between UF_NET rate and outcomes with both faster and slower UF_NET rates being associated with increased mortality compared with moderate UF_NET rates. Thus, randomized trials are required to determine optimal UF_NET rates in critically ill patients.

Dialysis modality-related disparities in sudden cardiac death: hemodialysis versus peritoneal dialysis

Background

Patients require risk stratification and preventive strategies for sudden cardiac death (SCD) based on the dialysis modality because the process of dialysis is a risk factor for SCD. This study aimed to compare the risk of SCD in patients undergoing hemodialysis (HD) versus peritoneal dialysis (PD).

Methods

Patients on HD and PD were included in the end-stage renal disease registry of the Korean Society of Nephrology between 1985 and 2017. The incidence and associated factors of SCD were analyzed based on the dialysis modality.

Results

Of 132,083 patients, 34,632 (26.2%) died during 94.8 ± 73.6 months of follow-up. In patients on HD and PD, 22.2% and 19.6% of total deaths were SCDs. In the propensity score-matched population, SCD accounted for 21.7% and 19.6% of total deaths in patients on HD and PD, respectively. HD was independently associated with SCD even after adjusting for age and significant comorbidities. Hypertension, coronary artery disease, and congestive heart failure, and age at the time of death < 65 years were independent risk factors for SCD in patients on HD but not in those on PD. Diabetes was significantly associated with SCD regardless of the dialysis modality.

Conclusion

Compared with patients on PD, Korean patients on HD have a higher risk of SCD, which is attributable to cardiac comorbidities.

Ultrafiltration Rate, Residual Kidney Function, and Survival Among Patients Treated With Reduced-Frequency Hemodialysis

RATIONALE & OBJECTIVE

Patients receiving twice-weekly or less-frequent hemodialysis (HD) may need to undergo higher ultrafiltration rates (UFRs) to maintain acceptable fluid balance. We hypothesized that higher UFRs are associated with faster decline in residual kidney function (RKF) and a higher rate of mortality.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

1,524 patients with kidney failure who initiated maintenance HD at a frequency of twice or less per week for at least 6 consecutive weeks at some time between 2007 and 2011 and for whom baseline data for UFR and renal urea clearance were available.

PREDICTOR

Average UFR during the first patient-quarter during less-frequent HD (<6, 6-<10, 10-<13, and≥13mL/h/kg).

OUTCOME

Time to all-cause and cardiovascular death, slope of decline in RKF during the first year after initiation of less-frequent HD (with slopes above the median categorized as rapid decline).

ANALYTICAL APPROACH

Cox proportional hazards regression for time to death and logistic regression for the analysis of rapid decline in RKF.

RESULTS

Among 1,524 patients, higher UFR was associated with higher all-cause mortality; HRs were 1.43 (95% CI, 1.09-1.88), 1.51 (95% CI, 1.08-2.10), and 1.76 (95% CI, 1.23-2.53) for UFR of 6 to<10, 10 to<13, and≥13mL/h/kg, respectively (reference: UFR < 6mL/h/kg). Higher UFR was also associated with higher cardiovascular mortality. Baseline RKF modified the association between UFR and mortality; the association was attenuated among patients with renal urea clearance≥5mL/min/1.73m². Higher UFR had a graded association with rapid decline in RKF; ORs were 1.73 (95% CI, 1.18-2.55), 1.89 (95% CI, 1.12-3.17), and 2.75 (95% CI, 1.46-5.18) at UFRs of 6 to<10, 10 to<13, and≥13mL/h/kg, respectively (reference: UFR < 6mL/h/kg).

LIMITATIONS

Residual confounding from unobserved differences across exposure categories.

CONCLUSIONS

Higher UFR was associated with worse outcomes, including shorter survival and more rapid loss of RKF, among patients receiving regular HD treatments at a frequency of twice or less per week.

Non-adherence to Haemodialysis, Interdialytic weight gain and cardiovascular mortality: a cohort study

Background

Patients with chronic kidney diseases (CKD) on haemodialysis (HD) have high morbidity and mortality rates, which are also due to the inherent risks associated with nephropathy. Non-adherence (NA) to the different demands of the treatment can have consequences for the outcome of patients undergoing HD; nevertheless, there are still doubts about such repercussions. This study was conducted to evaluate the association between NA to conventional HD and all-cause mortality and cardiovascular mortality.

Methods

We prospectively evaluated mortality in a 6-year period in a cohort of 255 patients on HD in northeast Brazil. The evaluated parameters of NA to HD were interdialytic weight gain (IDWG) ≥ 4% of dry weight (DW), hyperphosphatemia and regular attendance at treatment, assessed as the correlation between the periods on HD completed and those prescribed. We used the Cox multivariate regression model to analyse survival and the predictors of all-cause mortality and cardiovascular mortality.

Results

With a median follow-up period of 1493 days and a mortality rate of 9.1 per 100 people-years, there were 87 deaths, of which 54% were cardiovascular deaths. IDWG ≥4% of DW was associated with a risk of all-cause mortality however presenting a borderline outcome for cardiovascular mortality, with hazard ratios of 2.02 (CI 95% 1.17–3.49, p = 0.012) and 2.09 (CI 95% 1.01–4.35, p = 0.047), respectively. No significant association was found between other parameters of NA and mortality. Subgroup analysis showed that for patients with IDWG ≥4% of DW, malnutrition, age and diagnosis of cardiovascular and cerebrovascular diseases were associated with higher all-cause mortality.

Conclusions

IDWG ≥4% of DW was identified as an independent predictor of all-cause mortality and demonstrated a borderline outcome for cardiovascular mortality in patients on conventional HD. The occurrence of excessive IDWG in the presence of malnutrition represented a significant increase in the risk of death, indicating a subgroup of patients with a worse prognosis.

Ultrafiltration-profiled hemodialysis to reduce dialysis-related cardiovascular stress: Study protocol for a randomized controlled trial

Rapid fluid removal (ultrafiltration, UF) is associated with higher cardiovascular morbidity and mortality among individuals receiving maintenance hemodialysis (HD). Fluid removal rates that exceed vascular refill rates can result in hemodynamic instability, end-organ damage to the heart, kidneys, gut and brain, among other organs, and patient symptoms. There are no known evidence-based HD treatment strategies to reduce harm from higher UF rates. Ultrafiltration profiling, the practice of varying UF rates to maximize fluid removal during periods of greatest hydration and plasma oncotic pressure, has been proposed as an HD treatment intervention that may reduce UF rate-related complications. This study is a randomized 4-phase cross-over trial in which participants are successively alternated between study arms with intervening washout periods, and treatment order is randomized. After 4-week screening and 6-week baseline periods, participants are randomized to HD with conventional UF or HD with UF profiling for a period of 3 weeks followed by a 1-week washout period before crossing over. Participants cross into conventional UF and UF profiling phases twice (2 phases per arm). The primary outcomes of interest are intradialytic hypotension (nadir intradialytic systolic blood pressure <90 mmHg), pre-to post-HD change in troponin T (expressed as a percentage), change in left ventricular global longitudinal strain (an echocardiographic measure of left ventricular systolic function), and development of intradialytic left ventricular stunning (worsening of contractile function in ≥2 segments). This study will determine the impact of UF profiling on UF rate-related cardiovascular complications in prevalent, maintenance HD patients.

Association of Net Ultrafiltration Rate With Mortality Among Critically Ill Adults With Acute Kidney Injury Receiving Continuous Venovenous Hemodiafiltration: A Secondary Analysis of the Randomized Evaluation of Normal vs Augmented Level (RENAL) of Renal Replacement Therapy Trial

IMPORTANCE

Net ultrafiltration (NUF) is frequently used to treat fluid overload among critically ill patients, but whether the rate of NUF affects outcomes is unclear.

OBJECTIVE

To examine the association of NUF with survival among critically ill patients with acute kidney injury being treated with continuous venovenous hemodiafiltration.

DESIGN, SETTING, AND PARTICIPANTS

The Randomized Evaluation of Normal vs Augmented Level (RENAL) of Renal Replacement Therapy trial was conducted between December 30, 2005, and November 28, 2008, at 35 intensive care units in Australia and New Zealand among critically ill adults with acute kidney injury who were being treated with continuous venovenous hemodiafiltration. This secondary analysis began in May 2018 and concluded in January 2019.

EXPOSURES

Net ultrafiltration rate, defined as the volume of fluid removed per hour adjusted for patient body weight.

MAIN OUTCOMES AND MEASURES

Risk-adjusted 90-day survival.

RESULTS

Of 1434 patients, the median (interquartile range) age was 67.3 (56.9-76.3) years; 924 participants (64.4%) were male; median (interquartile range) Acute Physiology and Chronic Health Evaluation III score was 100 (84-118); and 634 patients (44.2%) died. Using tertiles, 3 groups were defined: high, NUF rate greater than 1.75 mL/kg/h; middle, NUF rate from 1.01 to 1.75 mL/kg/h; and low, NUF rate less than 1.01 mL/kg/h. The high-tertile group compared with the low-tertile group was not associated with death from day 0 to 6. However, death occurred in 51 patients (14.7%) in the high-tertile group vs 30 patients (8.6%) in the low-tertile group from day 7 to 12 (adjusted hazard ratio [aHR], 1.51; 95% CI, 1.13-2.02); 45 patients (15.3%) in the high-tertile group vs 25 patients (7.9%) in the low-tertile group from day 13 to 26 (aHR, 1.52; 95% CI, 1.11-2.07); and 48 patients (19.2%) in the high-tertile group vs 29 patients (9.9%) in the low-tertile group from day 27 to 90 (aHR, 1.66; 95% CI, 1.16-2.39). Every 0.5-mL/kg/h increase in NUF rate was associated with increased mortality (3-6 days: aHR, 1.05; 95% CI, 1.00-1.11; 7-12 days: aHR, 1.08; 95% CI, 1.02-1.15; 13-26 days: aHR, 1.11; 95% CI, 1.04-1.18; 27-90 days: aHR, 1.13; 95% CI, 1.05-1.22). Using longitudinal analyses, increase in NUF rate was associated with lower survival (β = .056; P < .001). Hypophosphatemia was more frequent among patients in the high-tertile group compared with patients in the middle-tertile group and patients in the low-tertile group (high: 308 of 477 patients at risk [64.6%]; middle: 293 of 472 patients at risk [62.1%]; low: 247 of 466 patients at risk [53.0%]; P < .001). Cardiac arrhythmias requiring treatment occurred among all groups: high, 176 patients (36.8%); middle: 175 patients (36.5%); and low: 147 patients (30.8%) (P = .08).

CONCLUSIONS AND RELEVANCE

Among critically ill patients, NUF rates greater than 1.75 mL/kg/h compared with NUF rates less than 1.01 mL/kg/h were associated with lower survival. Residual confounding may be present from unmeasured risk factors, and randomized clinical trials are required to confirm these findings.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00221013.

A swan song for Kt/Vurea

Dialyzer clearance of urea multiplied by dialysis time and normalized for urea distribution volume (Kt/V_urea or simply Kt/V) has been used as an index of dialysis adequacy since more than 30 years. This article reviews the flaws of Kt/V, starting with a lack of proof of concept in three randomized controlled hard outcome trials (RCTs), and continuing with a long list of conditions where the concept of Kt/V was shown to be flawed. This information leaves little room for any conclusion other than that Kt/V, as an indicator of dialysis adequacy, is obsolete. The dialysis patient might benefit more if, instead, the nephrology community concentrates in the future on pursuing the optimal dialysis dose that conforms with adequate quality of life and on factors that are likely to affect outcomes more than Kt/V. These include residual renal function, volume status, dialysis length, ultrafiltration rate, the number of intra-dialytic hypotensive episodes, interdialytic blood pressure, serum potassium and phosphate, serum albumin, and C reactive protein.

Assessment and management of fluid overload in children on dialysis

Dysregulation of intravascular fluid leads to chronic volume overload in children with end-stage kidney disease (ESKD). Sequelae include left ventricular hypertrophy and remodeling and impaired cardiac function. As a result, cardiovascular complications are the commonest cause of mortality in the pediatric dialysis population. The clinical need to optimize intravascular volume in children with ESKD is clear; however, its assessment and management is the most challenging aspect of the pediatric dialysis prescription. Minimizing chronic fluid overload is a key priority; however, excessive ultrafiltration is toxic to the myocardium and can precipitate intradialytic symptoms. This review outlines emerging objective techniques to enhance the assessment of fluid overload in children on dialysis and outlines evidence for current management strategies to address this clinical problem.

Net ultrafiltration intensity and mortality in critically ill patients with fluid overload

BACKGROUND

Although net ultrafiltration (UF^NET) is frequently used for treatment of fluid overload in critically ill patients with acute kidney injury, the optimal intensity of UF^NET is unclear. Among critically ill patients with fluid overload receiving renal replacement therapy (RRT), we examined the association between UF^NET intensity and risk-adjusted 1-year mortality.

METHODS

We selected patients with fluid overload ≥ 5% of body weight prior to initiation of RRT from a large academic medical center ICU dataset. UF^NET intensity was calculated as the net volume of fluid ultrafiltered per day from initiation of either continuous or intermittent RRT until the end of ICU stay adjusted for patient hospital admission body weight. We stratified UF^NET as low (≤ 20 ml/kg/day), moderate (> 20 to ≤ 25 ml/kg/day) or high (> 25 ml/kg/day) intensity. We adjusted for age, sex, body mass index, race, surgery, baseline estimated glomerular filtration rate, oliguria, first RRT modality, pre-RRT fluid balance, duration of RRT, time to RRT initiation from ICU admission, APACHE III score, mechanical ventilation use, suspected sepsis, mean arterial pressure on day 1 of RRT, cumulative fluid balance during RRT and cumulative vasopressor dose during RRT. We fitted logistic regression for 1-year mortality, Gray's survival model and propensity matching to account for indication bias.

RESULTS

Of 1075 patients, the distribution of high, moderate and low-intensity UF^NET groups was 40.4%, 15.2% and 44.2% and 1-year mortality was 59.4% vs 60.2% vs 69.7%, respectively (p = 0.003). Using logistic regression, high-intensity compared with low-intensity UF^NET was associated with lower mortality (adjusted odds ratio 0.61, 95% CI 0.41-0.93, p = 0.02). Using Gray's model, high UF^NET was associated with decreased mortality up to 39 days after ICU admission (adjusted hazard ratio range 0.50-0.73). After combining low and moderate-intensity UF^NET groups (n = 258) and propensity matching with the high-intensity group (n = 258), UF^NET intensity > 25 ml/kg/day compared with ≤ 25 ml/kg/day was associated with lower mortality (57% vs 67.8%, p = 0.01). Findings were robust to several sensitivity analyses.

CONCLUSIONS

Among critically ill patients with ≥ 5% fluid overload and receiving RRT, UF^NET intensity > 25 ml/kg/day compared with ≤ 20 ml/kg/day was associated with lower 1-year risk-adjusted mortality. Whether tolerating intensive UF^NET is just a marker for recovery or a mediator requires further research.

Patient-Centered Approach for Hypertension Management in End-Stage Kidney Disease: Art or Science?

Hypertension is present in most patients with end-stage kidney disease initiating dialysis and management of hypertension is a routine but challenging task in everyday dialysis care. End-stage kidney disease patients are uniquely heterogeneous individuals with significant variations in demographic characteristics, functional capacity, and presence of concomitant comorbid conditions and their severity. Therefore, these patients require personalized approaches in addressing not only hypertension but related illnesses, while also accounting for overall prognosis and projected longevity. There are only limited clinical trial data to guide individualized blood pressure management and current guidelines are based predominantly on observational evidence and expert opinions. Inthis review, we reflect on the shortcomings of peridialytic blood pressure recordings and discuss an important paradigm shift toward using out-of-dialysis blood pressure for evaluating hypertension control and for making treatment decisions. In addition, we provide our personal view on blood pressure goals and summarize nonpharmacologic and pharmacologic treatment options for individualized management of hypertension in end-stage kidney disease.

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.

Hypertension in Pediatric Dialysis Patients: Etiology, Evaluation, and Management

PURPOSE OF REVIEW

Review epidemiology, pathophysiology, and management of hypertension in the pediatric dialysis population.

RECENT FINDINGS

Interdialytic blood pressure measurement, especially with ambulatory blood pressure monitoring, is the gold standard to assess for hypertension. Tools to assess dry weight aid in achievement of euvolemia, the primary therapy for management of hypertension. Persistent hypertension should be treated with antihypertensive medications and potentially with native nephrectomies. Cardiovascular disease continues to be the primary cause of morbidity and mortality in the dialysis population with hypertension as an important modifiable factor. Achievement on dry weight and limiting both aggressiveness of interdialytic weight gain and ultrafiltration rate underlie the best approach. Tools to assess volume status beyond clinical assessment have shown promise in achieving euvolemia. When hypertension persists despite achievement of euvolemia, antihypertensive medications may be required and in some cases native nephrectomies. Future studies in children are needed to determine the best antihypertensive class and ideal rate of ultrafiltration on hemodialysis towards achievement of normotension and reduction of cardiovascular risk.

Barriers for implementation of intensified hemodialysis: survey results from the International Pediatric Dialysis Network

BACKGROUND

In patients on conventional hemodialysis (HD), morbidity is high and quality of life is poor. Intensified HD programs have been developed to help overcome these shortcomings, , but very few pediatric dialysis centers have reported the implementation of such a HD program.

METHODS

An online survey was sent to all 221 pediatric dialysis centers which participate in the International Pediatric Dialysis Network (IPDN). The aim of the survey was to assess the attitude of pediatric nephrologists towards intensified HD, the penetrance of intensified HD into their clinical practice and barriers to implementation.

RESULTS

Of the 221 pediatric dialysis centers sent the survey, respondents from 61% (134) replied. Among these respondents, 69% acknowledged being aware of the evidence in support of the use of intensified HD, independent of whether intensified HD was offered at their own center, and 50% associated the use of daily nocturnal HD with the best overall patient outcome. In contrast, only 2% of respondents were in favor of conventional HD. Overall, 38% of the respondents stated that at their center intensified HD is prescribed to a subgroup of patients, most commonly in the form of short daily HD sessions. The most important barriers to expansion of intensified HD programs were lack of adequate funding (66%) and shortage of staff (63%), whereas lack of expertise and of motivation were reported infrequently as obstacles (21 and 14%, respectively).

CONCLUSION

Intensified HD is considered by many pediatric nephrologists to be the dialysis modality most likely associated with the best patient outcome. The limited use of this treatment approach highlights the importance of defining and successfully addressing the barriers to implementation.

Should we look beyond Kt/V urea in assessing dialysis adequacy?

Since the advent of maintenance dialysis therapy, our interpretation of what adequate dialysis really is has broadened and become more controversial. This is not only due to our changing and aging dialysis population but also to our evolving knowledge base. As nephrologists, we strive to achieve both quality and (often) quantity of life for our patients and we feel reassured when we have a quantifiable marker to show for our efforts. However, we suggest that adequate dialysis reaches far beyond the realms of attaining a particular biochemical result. Dialysis adequacy should encompass a more comprehensive assessment of patient well-being. This metric could comprise quality of life and patient-specified goals, sufficient small solute and middle molecule clearance, optimal blood pressure control, and effective bone-mineral balance, all in the context of minimizing mortality and morbidity, and a livable dialysis regimen for the patient.

Hemodialysis Ultrafiltration Rate Targets Should Be Scaled to Body Surface Area Rather than to Body Weight

The association between higher ultrafiltration rates and poor outcomes in hemodialysis patients has received increased attention, to the point that various regulatory entities are considering adding ultrafiltration rate as a quality measure to be monitored and controlled. Most of the discussion to date has focused on ultrafiltration rate scaled to body weight, or more correctly, body mass (ml/hour per kg). One outcome study suggests that ultrafiltration rate might best be not scaled at all to body size, as modestly higher ultrafiltration rate in very small-size patients may be associated with some survival benefit, probably via increased dietary intake. Outcomes studies also suggest that the risk of exceeding a weight-scaled ultrafiltration target may be magnified in very large patients, and that body weight-scaled ultrafiltration targets in such patients should be set a lower level. Here, we present an analysis, based on physiological hemodynamic arguments, that it would be better to scale ultrafiltration rate to body surface area rather than to body mass. Whatever ultrafiltration rate is scaled to, attempts to restrict ultrafiltration rate by limiting interdialytic weight gain in small, possibly malnourished patients, should be done cautiously, to prevent an inadvertent lowering of intake of calories and dietary protein.

Long-term impacts of hemodialysis on the right ventricle: Assessment via 3-dimensional speckle-tracking echocardiography

BACKGROUND

Right ventricular (RV) dysfunction is a major cause of death in patients undergoing maintenance hemodialysis (MHD). We used 3-dimensional speckle-tracking echocardiography (3DSTE) to evaluate long-term impacts of MHD on RV function.

HYPOTHESIS

In this study, RV dysfunction in MHD patients will be revealed and studied in depth by 3DSTE.

METHODS

Echocardiography was performed on 110 consecutively enrolled individuals: 30 controls and 80 patients with MHD. Conventional echocardiographic parameters and 3DSTE parameters were obtained and compared between groups. Univariate and multivariate logistic regression analysis identified independent predictors of intradialytic hypotension (IDH).

RESULTS

Compared with the control group, RV end-diastolic volume (RVEDV) was markedly enlarged (46.1 ± 11.8 mL/m² vs 42.3 ± 8.6 mL/m² ; P = 0.047), whereas RV ejection fraction (RVEF) was significantly lower in the MHD group (50.6% ± 5.8% vs 55.2% ± 3.7%; P < 0.001). RV global, septal, and lateral wall longitudinal strains were also decreased in the MHD group (-18.2 ± 3.6 vs -22.6 ± 4.3%; -13.1 ± 3.8 vs -17.5 ± 5.5%; and -23.4 ± 4.7 vs -27.7 ± 4.0%, respectively; all P < 0.001). RVEF (odds ratio [OR]: 0.72, 95% confidence interval [CI]: 0.51 to 1.01, P = 0.038) and history of diabetes (OR: 11.14, 95% CI: 1.16 to 106.71, P = 0.036) were 2 independent predictors of IDH. Ultrafiltration rate was an independent factor associated with RVEF (β = -0.01, 95% CI: -0.019 to 0.001, P = 0.039).

CONCLUSIONS

RVEF by 3DSTE could be an important predictor of IDH in MHD patients, and lower ultrafiltration rate was protective for RVEF. 3DSTE may have potential in RV evaluation and risk stratification in MHD patients.

Association of Ultrafiltration Rate with Mortality in Incident Hemodialysis Patients

BACKGROUND/AIMS

Ultrafiltration rate (UFR) appears to be associated with mortality in prevalent hemodialysis (HD) patients. However, the association of UFR with mortality in incident HD patients remains unknown.

METHODS

We examined a US cohort of 110,880 patients who initiated HD from 2007 to 2011. Baseline UFR was divided into 5 groups (<4, 4 to <6, 6 to <8, 8 to <10, and ≥10 mL/h/kg body weight [BW]). We examined predictors of higher baseline UFR using logistic regression and the association of baseline UFR and all-cause and cardiovascular (CV) mortality using Cox proportional hazard models with adjustments for demographics, comorbidities, and markers of malnutrition-inflammation-cachexia syndrome.

RESULTS

Patients were 63 ± 15 years, with 43% women, 32% African Americans, and had a mean baseline UFR of 7.5 ± 3.1 mL/h/kg BW. In the fully adjusted logistic regression models, factors associated with higher UFR (≥7.5 mL/h/kg BW) included Hispanic ethnicity, diabetes, and higher dietary protein intake. There was a linear association between UFR and all-cause and CV mortality, where UFR ≥10 mL/h/kg BW (reference UFR 6-<8 mL/h/kg BW) conferred the highest risk in both unadjusted (HR 1.15 [95% CI 1.10-1.19]) and adjusted models (HR 1.23 [95% CI 1.16-1.31]). The linear association with all-cause mortality remained consistent across strata of age, urine volume, and treatment time.

CONCLUSIONS

Higher UFR is independently associated with higher all-cause and CV mortality in incident HD patients. Clinical trials are warranted to examine the effects of lowering UFR on outcomes.

Study on Dialysis Session Length and Mortality in Maintenance Hemodialysis Patients: The Q-Cohort Study

<b><i>Objectives:</i></b> Hemodialysis (HD) time has been recognized as an important factor in dialysis adequacy. However, few studies have reported on associations between HD time and prognosis among maintenance HD patients. We present some findings from a prospective cohort study, the ­Q-Cohort Study, which was set up to explore risk factors for mortality in Japanese HD patients. We hypothesized that HD ≥5 h was associated with a significant survival advantage compared with HD &#x3c; 5 h. The present study examined association between HD time and mortality in Japanese HD patients. <b><i>Methods:</i></b> The prospective multicenter Q-Cohort Study was conducted between December 2006 and December 2010, following 3,456 Japanese HD patients for 4 years. We examined the association between HD time and prognosis using Cox proportional hazards modeling. Propensity scores were calculated using logistic regression. <b><i>Results:</i></b> During follow-up, 566 patients died from any cause. Patients with HD ≥5 h (<i>n</i> = 2,141) showed ­significantly lower risk of all-cause death (hazards ratio = 0.82; 95% CI 0.68–0.99) than those with HD &#x3c; 5 h (<i>n</i> = 1,315), after adjusting for confounding risk factors. This ­association remained significant using a propensity score-based approach. After stratifying the analysis by patient age in 10-year increments, this finding remained ­significant only in patients who were ≥80 years of age. <b><i>Conclusion:</i></b> Our results suggest that HD ≥5 h has a more favorable effect on mortality than HD &#x3c; 5 h.

A brief review of intradialytic hypotension with a focus on survival

Intradialytic hypotension (IDH), a common complication of ultrafiltration during hemodialysis therapy, is associated with high mortality and morbidity. IDH, defined as a nadir systolic blood pressure of less than 90 mm Hg on more than 30% of treatments, is a relevant definition and is correlated with mortality. Risk factors for IDH include patient demographics, anti-hypertensive medication use, larger interdialytic weight gain, and dialysis prescription features as dialysate sodium, high ultrafiltration rate, and dialysate temperature. A high frequency of IDH events carries a substantial death risk. An ultrafiltration rate >10 mL/h/kg, and even more so >13 mL/h/kg, is highly predictive of cardiovascular and all-cause mortality. Evidence suggests that IDH causes acute reversible segmental myocardial hypoperfusion and contractile dysfunction (myocardial stunning), which can result in long-term loss of myocardial contractility, leading to premature death. IDH also has negative end-organ effects on the brain and gut, contributing to mortality through stroke, and endotoxin translocation with associated inflammation and protein-energy wasting. Given strong association of IDH and dialysis mortality, a paradigm shift to its approach is urgently needed. Randomized controlled trials are required to prospectively test drugs and monitoring devices which may reduce IDH.

Hypertension in dialysis patients: a consensus document by the European Renal and Cardiovascular Medicine (EURECA-m) working group of the European Renal Association - European Dialysis and Transplant Association (ERA-EDTA) and the Hypertension and the Kidney working group of the European Society of Hypertension (ESH)

In patients with end-stage renal disease treated with hemodialysis or peritoneal dialysis, hypertension is very common and often poorly controlled. Blood pressure (BP) recordings obtained before or after hemodialysis display a J-shaped or U-shaped association with cardiovascular events and survival, but this most likely reflects the low accuracy of these measurements and the peculiar hemodynamic setting related with dialysis treatment. Elevated BP by home or ambulatory BP monitoring is clearly associated with shorter survival. Sodium and volume excess is the prominent mechanism of hypertension in dialysis patients, but other pathways, such as arterial stiffness, activation of the renin-angiotensin-aldosterone and sympathetic nervous systems, endothelial dysfunction, sleep apnea and the use of erythropoietin-stimulating agents may also be involved. Nonpharmacologic interventions targeting sodium and volume excess are fundamental for hypertension control in this population. If BP remains elevated after appropriate treatment of sodium-volume excess, the use of antihypertensive agents is necessary. Drug treatment in the dialysis population should take into consideration the patient's comorbidities and specific characteristics of each agent, such as dialysability. This document is an overview of the diagnosis, epidemiology, pathogenesis and treatment of hypertension in patients on dialysis, aiming to offer the renal physician practical recommendations based on current knowledge and expert opinion and to highlight areas for future research.

Short, frequent, 5-days-per-week, in-center hemodialysis versus 3-days-per week treatment: a randomized crossover pilot trial through the Midwest Pediatric Nephrology Consortium

BACKGROUND

No controlled trials in children with end-stage kidney disease have assessed the benefits of more frequently administered hemodialysis (HD).

METHODS

We conducted a multicenter, crossover pilot trial to determine if short, more frequent (5 days per week) in-center HD was feasible and associated with improvements in blood pressure compared with three conventional HD treatments per week. Because adult studies have not controlled for the weekly duration of dialysis, we fixed the total treatment time at 12 h a week of dialysis during two 3-month study periods; only frequency varied from 5 to 3 days per week between study periods.

RESULTS

Eight children (median age 16.7 years) consented at three children's hospitals. The prespecified primary composite outcome was a sustained 10% decrease in systolic blood pressure and/or a decrease in antihypertensive medications relative to each study period's baseline. Among the six patients completing both study periods, five (83.3%) experienced the primary outcome during HD performed 5 days per week but not 3 days per week; one of the six (16.7%) achieved that outcome during 3-day but not 5-day (p = 0.22) per week HD. During 5-day HD, all patients had significantly more treatments during which their pre-HD systolic (p = 0.01) or diastolic (p = 0.01) blood pressure was 10% lower than baseline.

CONCLUSIONS

We observed that more frequent HD sessions per week was feasible and associated with improved blood pressure control, but barriers to changing thrice-weekly standard of care include financial reimbursement and the time demands associated with more frequent treatments.

The effect of treatment time, dialysis frequency, and ultrafiltration rate on intradialytic hypotension

Dialysis treatment time, the frequency of dialysis treatments, and the rate of fluid ultrafiltration-each impacts the incidence of intradialytic hypotension. These factors influence blood pressure independently and together. The strongest evidence supports that rapid ultrafiltration increases the likelihood of intradialytic hypotension and that combined strategies leading to a reduction in ultrafiltration rate have the greatest impact on reducing intradialytic hypotension. A practical approach to avoiding the effects of ultrafiltration on systemic hemodynamics would be to set a maximum ultrafiltration rate needed to achieve the desired fluid removal and vary the duration of the treatment to achieve that target volume. Randomized, controlled clinical trials of such strategies are warranted.

Effects of weight-based ultrafiltration rate limits on intradialytic hypotension in hemodialysis

INTRODUCTION

High ultrafiltration (UF) rates can result in intradialytic hypotension and are associated with increased mortality. The effects of a weight-based UF rate limit on intradialytic hypotension and the potential for unwanted fluid weight gain and hospitalizations for volume overload are unknown.

METHODS

This retrospective cohort study examined 123 in-center hemodialysis patients at one facility who transitioned to 13 mL/kg/h maximum UF rates. Patients were studied for an 8 week UF rate limit exposure period and compared to the 8-week period immediately prior, during which the cohort served as its own historical control. The primary outcomes were frequency of intradialytic hypotension events and percentage of treatments with a hypotension event.

FINDINGS

The delivered UF rate was lower during the exposure compared to the baseline period (mean UF rate 7.90 ± 4.45 mL/kg/h vs. 8.92 ± 5.64 mL/kg/h; P = 0.0005). The risk of intradialytic hypotension was decreased during the exposure compared to baseline period (event rate per treatment 0.0569 vs. 0.0719, OR 0.78 [95% CI 0.62-1.00]; P = 0.0474), as was the risk of having a treatment with a hypotension event (percentage of treatments with event 5.2% vs. 6.8%, OR 0.75 [95% CI 0.58-0.96]; P = 0.0217). Subgroup analyses demonstrated that these findings were attributable to patients with high baseline UF rates. Statistically significant differences in all-cause or volume overload-related hospitalization were not observed during the exposure period.

DISCUSSION

A weight-based UF rate limit of 13 mL/kg/h was associated with a decrease in the rate of intradialytic hypotension events among in-center hemodialysis patients.

Hypertension in dialysis patients: a consensus document by the European Renal and Cardiovascular Medicine (EURECA-m) working group of the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) and the Hypertension and the Kidney working group of the European Society of Hypertension (ESH)

In patients with end-stage renal disease (ESRD) treated with haemodialysis or peritoneal dialysis, hypertension is common and often poorly controlled. Blood pressure (BP) recordings obtained before or after haemodialysis display a J- or U-shaped association with cardiovascular events and survival, but this most likely reflects the low accuracy of these measurements and the peculiar haemodynamic setting related to dialysis treatment. Elevated BP detected by home or ambulatory BP monitoring is clearly associated with shorter survival. Sodium and volume excess is the prominent mechanism of hypertension in dialysis patients, but other pathways, such as arterial stiffness, activation of the renin-angiotensin-aldosterone and sympathetic nervous systems, endothelial dysfunction, sleep apnoea and the use of erythropoietin-stimulating agents may also be involved. Non-pharmacologic interventions targeting sodium and volume excess are fundamental for hypertension control in this population. If BP remains elevated after appropriate treatment of sodium and volume excess, the use of antihypertensive agents is necessary. Drug treatment in the dialysis population should take into consideration the patient's comorbidities and specific characteristics of each agent, such as dialysability. This document is an overview of the diagnosis, epidemiology, pathogenesis and treatment of hypertension in patients on dialysis, aiming to offer the renal physician practical recommendations based on current knowledge and expert opinion and to highlight areas for future research.

Target weight achievement and ultrafiltration rate thresholds: potential patient implications

BACKGROUND

Higher ultrafiltration (UF) rates and extracellular hypo- and hypervolemia are associated with adverse outcomes among maintenance hemodialysis patients. The Centers for Medicare and Medicaid Services recently considered UF rate and target weight achievement measures for ESRD Quality Incentive Program inclusion. The dual measures were intended to promote balance between too aggressive and too conservative fluid removal. The National Quality Forum endorsed the UF rate measure but not the target weight measure. We examined the proposed target weight measure and quantified weight gains if UF rate thresholds were applied without treatment time (TT) extension or interdialytic weight gain (IDWG) reduction.

METHODS

Data were taken from the 2012 database of a large dialysis organization. Analyses considered 152,196 United States hemodialysis patients. We described monthly patient and dialysis facility target weight achievement patterns and examined differences in patient characteristics across target weight achievement status and differences in facilities across target weight measure scores. We computed the cumulative, theoretical 1-month fluid-related weight gain that would occur if UF rates were capped at 13 mL/h/kg without concurrent TT extension or IDWG reduction.

RESULTS

Target weight achievement patterns were stable over the year. Patients who did not achieve target weight (post-dialysis weight ≥ 1 kg above or below target weight) tended to be younger, black and dialyze via catheter, and had shorter dialysis vintage, greater body weight, higher UF rate and more missed treatments compared with patients who achieved target weight. Facilities had, on average, 27.1 ± 9.7% of patients with average post-dialysis weight ≥ 1 kg above or below the prescribed target weight. In adjusted analyses, facilities located in the midwest and south and facilities with higher proportions of black and Hispanic patients and higher proportions of patients with shorter TTs were more likely to have unfavorable facility target weight measure scores. Without TT extension or IDWG reduction, UF rate threshold (13 mL/h/kg) implementation led to an average theoretical 1-month, fluid-related weight gain of 1.4 ± 3.0 kg.

CONCLUSIONS

Target weight achievement patterns vary across clinical subgroups. Implementation of a maximum UF rate threshold without adequate attention to extracellular volume status may lead to fluid-related weight gain.

Higher Ultrafiltration Rate Is Associated with Longer Dialysis Recovery Time in Patients Undergoing Conventional Hemodialysis

BACKGROUND

Increased mortality and morbidity are reported in association with high ultrafiltration rate (UFR) and with long dialysis recovery time (DRT). We studied the association between UFR and DRT.

METHODS

This is a cross-sectional, observational study was conducted. Patients on thrice-weekly hemodialysis (HD) with self-reported DRT between August and December 2014 were included. We examined the association of 30-day average UFR with recovery time.

RESULTS

The total number of patients included in this study was 2,689. DRT in categories of immediate recovery, >0-≤2, >2-≤6, >6-≤12, and >12 h, were reported in 27, 28, 17, 9, and 20% of the patients respectively. In multivariable analysis, longer DRT was associated with female gender, non-black race, higher body weight, lower serum albumin, chronic heart failure, cerebrovascular disease, missed dialysis sessions, higher pre-dialysis systolic blood pressure, and larger UF volume. Compared to UFR of <10, UFR ≥13 mL/kg/h was associated with longer DRT, OR of 1.16 (95% CI 0.99-1.36), and 1.28 (95% CI 1.06-1.54) in the unadjusted and the adjusted analyses respectively. Intradialytic hypotension was also associated with longer DRT in the unadjusted (per 10% higher frequency, OR 1.04 [95% CI 1.01-1.07]) and adjusted analyses (OR 1.03 [95% CI 1.00-1.07]).

CONCLUSION

Long recovery time is common after HD. Rapid fluid removal is associated with longer DRT.

The Use of a Multidimensional Measure of Dialysis Adequacy-Moving beyond Small Solute Kinetics

Urea removal has become a key measure of the intensity of dialysis treatment for kidney failure. Small solute removal, exemplified by Kt/Vurea, has been broadly applied as a means to quantify the dose of thrice weekly hemodialysis. Yet, the reliance on small solute clearances alone as a measure of dialysis adequacy fails fully to quantify the intended clinical effects of dialysis therapy. This review aims to (1) understand the strengths and limitations of small solute kinetics as a surrogate marker of dialysis dose, and (2) present the prospect of a more comprehensive construct for dialysis dose, one that considers more broadly the goals of ESRD care to maximize both quality of life and survival. On behalf of the American Society of Nephrology Dialysis Advisory Group, we propose the need to ascertain the validity and utility of a multidimensional measure that moves beyond small solute kinetics alone to quantify optimal dialysis derived from both patient-reported and comprehensive clinical and dialysis-related measures.

Even a Moderate Fluid Removal Rate during Individualised Haemodialysis Session Times Is Associated with Decreased Patient Survival

Background: Several studies report that fluid removal rate (FRR) above 10-13 mL/h/kg is associated with increased mortality in haemodialysis (HD) patients. Aim: The aims of this study are to assess the influence of moderate FRR on survival in a cohort of prevalent dialysis patients with various dialysis session times and to challenge the FRR thresholds associated with increased mortality risk reported previously. Methods: Interdialytic weight gain (IDWG) and FRR (calculated from ultrafiltration [UF], target weight, and session time prescriptions) were studied in 190 prevalent dialysis patients (female: 42%, mean age: 69.5 years, median vintage: 40.2 months, diabetes: 34.7%, loop diuretic prescription: 5.8%) and averaged during the final quarter of 2010. Patient survival was analysed using Kaplan-Meier and Cox-multivariate analyses. Results: The median IDWG, median session time, and median FRR were 2.33 kg (-0.54-4.57), 5.0 h (3.9-8.0 h), 6.8 mL/h/kg (1.3-16.7), respectively, and FRR was ≥10 mL/h/kg in 11.6% of the patients. The Kaplan-Meier analysis showed decreased patient survival when the FRR was above the median (6.8 mL/h/kg; p = 0.012). The FRR was found to be independently associated with increased mortality (hazard ratio 1.15 [95% CI 1.02-1.29]; p = 0.027) using stepwise Cox proportional hazard regression analysis, including age, vintage, gender, body mass index (BMI), serum albumin level, β2-microglobulin level, cardiovascular and diabetes history, and session time. Online haemodiafiltration did not change this result. The role of residual renal function was unlikely because 74% of the patients had a vintage of >18 months, a minority (5.8%) were prescribed loop diuretics (a surrogate of significant urine output) and β2-microglobulin level was not different in patients who were below or above the FRR median. Conclusion: We concluded that the FRR threshold above which there is an increased mortality is lower than what has been reported (7.8 mL/h/kg). It raises the question of the hazard of fluid removal and intermittence of standard HD.

Treatment tolerance and patient-reported outcomes favor online hemodiafiltration compared to high-flux hemodialysis in the elderly

Large cohort studies suggest that high convective volumes associated with online hemodiafiltration may reduce the risk of mortality/morbidity compared to optimal high-flux hemodialysis. By contrast, intradialytic tolerance is not well studied. The aim of the FRENCHIE (French Convective versus Hemodialysis in Elderly) study was to compare high-flux hemodialysis and online hemodiafiltration in terms of intradialytic tolerance. In this prospective, open-label randomized controlled trial, 381 elderly chronic hemodialysis patients (over age 65) were randomly assigned in a one-to-one ratio to either high-flux hemodialysis or online hemodiafiltration. The primary outcome was intradialytic tolerance (day 30-day 120). Secondary outcomes included health-related quality of life, cardiovascular risk biomarkers, morbidity, and mortality. During the observational period for intradialytic tolerance, 85% and 84% of patients in high-flux hemodialysis and online hemodiafiltration arms, respectively, experienced at least one adverse event without significant difference between groups. As exploratory analysis, intradialytic tolerance was also studied, considering the sessions as a statistical unit according to treatment actually received. Over a total of 11,981 sessions, 2,935 were complicated by the occurrence of at least one adverse event, with a significantly lower occurrence in online hemodiafiltration with fewer episodes of intradialytic symptomatic hypotension and muscle cramps. By contrast, health-related quality of life, morbidity, and mortality were not different in both groups. An improvement in the control of metabolic bone disease biomarkers and β2-microglobulin level without change in serum albumin concentration was observed with online hemodiafiltration. Thus, overall outcomes favor online hemodiafiltration over high-flux hemodialysis in the elderly.

Sudden Cardiac Death Among Hemodialysis Patients

Hemodialysis patients carry a large burden of cardiovascular disease; most onerous is the high risk for sudden cardiac death. Defining sudden cardiac death among hemodialysis patients and understanding its pathogenesis are challenging, but inferences from the existing literature reveal differences between sudden cardiac death among hemodialysis patients and the general population. Vascular calcifications and left ventricular hypertrophy may play a role in the pathophysiology of sudden cardiac death, whereas traditional cardiovascular risk factors seem to have a more muted effect. Arrhythmic triggers also differ in this group as compared to the general population, with some arising uniquely from the hemodialysis procedure. Combined, these factors may alter the types of terminal arrhythmias that lead to sudden cardiac death among hemodialysis patients, having important implications for prevention strategies. This review highlights current knowledge on the epidemiology, pathophysiology, and risk factors for sudden cardiac death among hemodialysis patients. We then examine strategies for prevention, including the use of specific cardiac medications and device-based therapies such as implantable defibrillators. We also discuss dialysis-specific prevention strategies, including minimizing exposure to low potassium and calcium dialysate concentrations, extending dialysis treatment times or adding sessions to avoid rapid ultrafiltration, and lowering dialysate temperature.

Impact of rapid ultrafiltration rate on changes in the echocardiographic left atrial volume index in patients undergoing haemodialysis: a longitudinal observational study

OBJECTIVE

Optimal fluid management is essential when caring for a patient on haemodialysis (HD). However, if the fluid removal is too rapid, the resultant higher ultrafiltration rate (UFR) disadvantageously promotes haemodynamic instability and cardiac injury. We evaluated the effects of a rapid UFR on changes in the echocardiographic left atrial volume index (LAVI) over a period of time.

DESIGN

Longitudinal observational study.

SETTING AND PARTICIPANTS

A total of 124 new patients on HD.

INTERVENTIONS

Echocardiography was performed at baseline and repeated after 19.7 months (range 11.3-23.1 months). Changes in LAVI (ΔLAVI/year, mL/m²/year) were calculated. The UFR was expressed in mL/hour/kg, and we used the mean UFR over 30 days (∼12-13 treatments).

MAIN OUTCOME MEASURES

The 75th centile of the ΔLAVI/year distribution was regarded as a 'pathological' increment.

RESULTS

The mean interdialytic weight gain was 1.73±0.94 kg, and the UFR was 8.01±3.87 mL/hour/kg. The significant pathological increment point in ΔLAVI/year was 4.89 mL/m²/year. Correlation analysis showed that ΔLAVI/year was closely related to the baseline blood pressure, haemoglobin level, residual renal function and UFR. According to the receiver operating characteristics curve, the 'best' cut-off value of UFR for predicting the pathological increment was 10 mL/hour/kg, with an area under the curve of 0.712. In multivariate analysis, systolic blood pressure, a history of coronary artery disease, haemoglobin <10 g/dL and high UFR were significant predictors. An increase of 1 mL/hour/kg in the UFR was associated with a 22% higher risk of a worsening LAVI (OR 1.22, 95% CI 1.05 to 1.41).

CONCLUSIONS

An increased haemodynamic load could affect left atrial remodelling in incident patients on HD. Thus, close monitoring and optimal control of UFR are needed.

Comparison of multiple fluid status assessment methods in patients on chronic hemodialysis

PURPOSE

Control of hydration status is an important constituent of adequate and efficient hemodialysis (HD) treatment. Nevertheless, there are no precise clinical indices for early recognition of small changes in fluid status of patients undergoing chronic hemodialysis therapy. This study aimed to evaluate and compare the widely used and reliable method of indexed inferior vena cava diameter (IVCDi) with established and more recently available techniques (bioelectrical impedance analysis [BIA], continuous blood volume monitoring [Crit-line], and the B-line score [BLS] with lung ultrasonography) for estimating the hydration status of patients on HD.

METHODS

Fifty-three patients undergoing chronic HD thrice weekly were included in the study. Evaluation of hydration status methods (IVCDi, BLS, BIA, and Crit-line) was performed thrice weekly before and after HD. Receiver operating characteristic curve analysis was performed to evaluate the discriminative power of (methods) the BLS, BIA, and Crit-line for predicting over- and underhydration of patients, as determined by the reference method, IVCDi.

RESULTS

BLS showed the most promising results in predicting overhydration, as determined by IVCDi, compared with BIA and Crit-line and presented a sensitivity of 77% and specificity of 74%. The accuracy of the BLS was higher than that of BIA (0.81 vs. 0.71, p = 0.032) and Crit-line (0.61, p = 0.001). BLS also showed more promising results in predicting underhydration, as determined by IVCDi, than BIA and Crit-line and presented a sensitivity of 78% and a specificity of 73%. The accuracy of the BLS was higher than that of BIA (0.83 vs. 0.76, p = 0.035) and Crit-line (0.50, p < 0.001).

CONCLUSIONS

The BLS is a useful and easily performed technique that has recently become available for accurate evaluation of dry weight and fluid status in patients with end-stage renal disease undergoing chronic HD. This method might help recognize asymptomatic lung congestion in these patients.

Identification of volume overload hospitalizations among hemodialysis patients using administrative claims: a validation study

BACKGROUND

High rates of volume overload hospitalizations may indicate inadequate dialysis facility fluid management. Administrative claims databases are often used to study such outcomes, but these data are generated for billing purposes and may not capture clinical nuance. It is unknown if volume overload admissions can be correctly identified in administrative data and if a single claims-based definition for volume overload can be used across epidemiologic surveillance studies, observational studies of exposure-outcome associations and quality assessments. We conducted a validation study to assess the accuracy of claims-based definitions for volume overload hospitalizations among hemodialysis patients.

METHODS

Data were taken from a random sample of 315 adult hemodialysis patients admitted to University of North Carolina Hospitals from January 2010 through June 2013. Standardized chart reviews were conducted to clinically adjudicate the presence or absence of volume overload at hospital admission. Claims-based definitions were constructed from varying combinations of fluid-related ICD-9 discharge diagnosis codes including fluid overload, pulmonary edema, pleural effusion, and heart failure. Using clinically adjudicated volume overload hospitalizations as the reference standard, validity metrics and their 95 % confidence intervals (CIs) were estimated for each definition.

RESULTS

Of the 315 hospital admissions, 77 (24.4 %) were clinically adjudicated as volume overload hospitalizations. The prevalence of claims-identified volume overload admissions varied across definitions, ranging from 1.6 to 37.1 %. When definitions were constructed with discharge diagnosis codes present in any billing position, volume overload hospitalizations defined by fluid overload, pleural effusion or heart failure diagnosis codes had the highest sensitivity, 81.8 % (95 % CI: 71.4 %, 89.7 %). Volume overload hospitalizations defined by pulmonary edema diagnosis codes had the highest specificity, 98.3 % (95 % CI: 95.8 %, 99.5 %). Definitions constructed with discharge diagnosis codes present in any billing position (versus the primary position) captured more false positive events.

CONCLUSIONS

Prevalence and validity estimates of volume overload hospitalizations vary across claims-based definitions. A universal claims-based definition for volume overload hospitalizations may not apply to all clinical and research scenarios. Investigators and regulators need to consider the implications of misclassifying events when evaluating and monitoring hemodialysis patient volume overload admissions with administrative data. Claims-based definitions should be selected accordingly.

Ultrafiltration Rate and Mortality in Maintenance Hemodialysis Patients

BACKGROUND

Observational data have demonstrated an association between higher ultrafiltration rates and greater mortality among hemodialysis patients. Prior studies were small and did not consider potential differences in the association across body sizes and other related subgroups. No study has investigated ultrafiltration rates normalized to anthropometric measures beyond body weight. Also, potential methodological shortcomings in prior studies have led to questions about the veracity of the ultrafiltration rate-mortality association.

STUDY DESIGN

Retrospective cohort.

SETTING & PARTICIPANTS

118,394 hemodialysis patients dialyzing in a large dialysis organization, 2008 to 2012.

PREDICTORS

Mean 30-day ultrafiltration rates were dichotomized at 13 and 10mL/h/kg, separately and categorized using various cutoff points. Ultrafiltration rates normalized to body weight, body mass index, and body surface area were investigated.

OUTCOMES

All-cause mortality.

MEASUREMENTS

Multivariable survival models were used to estimate the association between ultrafiltration rate and all-cause mortality.

RESULTS

At baseline, 21,735 (18.4%) individuals had ultrafiltration rates > 13mL/h/kg and 48,529 (41.0%) had ultrafiltration rates > 10mL/h/kg. Median follow-up was 2.3 years, and the mortality rate was 15.3 deaths/100 patient-years. Compared with ultrafiltration rates ≤ 13mL/h/kg, ultrafiltration rates > 13mL/h/kg were associated with greater mortality (adjusted HR, 1.31; 95% CI, 1.28-1.34). Compared with ultrafiltration rates ≤ 10mL/h/kg, ultrafiltration rates > 10mL/h/kg were associated with greater mortality (adjusted HR, 1.22; 95% CI, 1.20-1.24). Findings were consistent across subgroups of sex, race, dialysis vintage, session duration, and body size. Higher ultrafiltration rates were associated with greater mortality when normalized to body weight, body mass index, and body surface area.

LIMITATIONS

Residual confounding cannot be excluded given the observational study design.

CONCLUSIONS

Regardless of the threshold implemented, higher ultrafiltration rate was associated with greater mortality in the overall study population and across key subgroups. Randomized controlled trials are needed to investigate whether ultrafiltration rate reduction improves clinical outcomes.

Incremental Hemodialysis: How I Do It

Incremental hemodialysis (incrHD) is not widely used nor is it well understood. In addition, and perhaps with more impact, governmental regulations in the United States and their consequential influences on dialysis provider organizations have made the practice of incrHD more difficult than traditional thrice weekly in-center HD. IncrHD is critically dependent on the amount of residual kidney function (RKF) as well as the individualized goals of end-stage renal disease (ESRD) management. RKF has to be assessed frequently and dialysis adjusted accordingly. Home HD lends itself to an incremental approach more so than in-center HD. This may be due to more experience of the provider, more knowledge of the therapy by the patient and family, the availability of dialysis platforms conducive to incrHD, and/or that its less onerous regulation by the government. I have had a long and successful experience performing incremental dialysis (both peritoneal and hemodialysis) and share here my practice strategies and approaches for incrHD.

Rapid ultrafiltration rates and outcomes among hemodialysis patients: re-examining the evidence base

PURPOSE OF REVIEW

This review critically summarizes the evidence linking ultrafiltration rates to adverse outcomes among hemodialysis patients and provides research recommendations to address knowledge gaps.

RECENT FINDINGS

Growing evidence suggests that fluid-related factors play important roles in hemodialysis patient outcomes. Ultrafiltration rate - the rate of fluid removal during hemodialysis - is one such factor. Existing observational data suggest a robust association between greater ultrafiltration rates and adverse cardiovascular outcomes, and such findings are supported by plausible physiologic rationale. Potential mechanistic pathways include ultrafiltration-related ischemia to the heart, brain, and gut, and volume overload-precipitated cardiac stress from reactive measures to ultrafiltration-induced hemodynamic instability. Inter-relationships among ultrafiltration rates and other fluid measures, such as interdialytic weight gain and chronic volume expansion, render the specific role of ultrafiltration rates in adverse outcomes difficult to study. Randomized trials must be conducted to confirm epidemiologic findings and examine the effect of ultrafiltration rate reduction on clinical and patient-centered outcomes.

SUMMARY

Compelling observational data demonstrate an association between more rapid ultrafiltration rates and adverse clinical outcomes. Before translating these findings into clinical practice, randomized trials are needed to verify observational data results and to identify effective strategies to mitigate ultrafiltration-related risk.

Ultrafiltration Rates and the Quality Incentive Program: Proposed Measure Definitions and Their Potential Dialysis Facility Implications

BACKGROUND AND OBJECTIVES

Rapid ultrafiltration rates are associated with adverse outcomes among patients on hemodialysis. The Centers for Medicare and Medicaid Services is considering an ultrafiltration rate quality measure for the ESRD Quality Incentive Program. Two measure developers proposed ultrafiltration rate measures with different selection criteria and specifications. We aimed to compare the proposed ultrafiltration rate measures and quantify dialysis facility operational burden if treatment times were extended to lower ultrafiltration rates.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data were taken from the 2012 database of a large dialysis organization. Analyses of the Centers for Medicare and Medicaid Services measure considered 148,950 patients on hemodialysis, and analyses of the Kidney Care Quality Alliance measure considered 151,937 patients. We described monthly patient and facility ultrafiltration rates and examined differences in patient characteristics across ultrafiltration rate thresholds and differences in facilities across ultrafiltration rate measure scores. We computed the additional treatment time required to lower ultrafiltration rates <13 ml/h per kilogram.

RESULTS

Ultrafiltration rates peaked in winter and nadired in summer. Patients with higher ultrafiltration rates were younger; more likely to be women, nonblack, Hispanic, and lighter in weight; and more likely to have histories of heart failure compared with patients with lower ultrafiltration rates. Facilities had, on average, 20.8%±10.3% (July) to 22.8%±10.6% (February) of patients with ultrafiltration rates >13 ml/h per kilogram by the Centers for Medicare and Medicaid Services monthly measure. Facilities had, on average, 15.8%±8.2% of patients with ultrafiltration rates ≥13 ml/h per kilogram by the Kidney Care Quality Alliance annual measure. Larger facilities (>100 patients) would require, on average, 33 additional treatment hours per week to lower all facility ultrafiltration rates <13 ml/h per kilogram when total treatment time is capped at 4 hours.

CONCLUSIONS

Ultrafiltration rates vary seasonally and across clinical subgroups. Extension of treatment time as a strategy to lower ultrafiltration rates may pose facility operational challenges. Prospective studies of ultrafiltration rate threshold implementation are needed.

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

BACKGROUND

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

STUDY DESIGN

A longitudinal cohort.

SETTING & PARTICIPANTS

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

PREDICTOR

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

OUTCOMES

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

RESULTS

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

LIMITATIONS

Potential selection bias and wide CIs.

CONCLUSIONS

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

Quantification of autonomic nervous activity by heart rate variability and approximate entropy in high ultrafiltration rate during hemodialysis

BACKGROUND

Few studies have focused on the imbalance of the autonomic nervous system in ultrafiltration rate (UFR) subjects without blood pressure variation during maintenance hemodialysis (HD), although the role of autonomic nervous system activation during HD has been proposed to be an important factor for the maintenance of blood pressure.

METHODS

Variations over time in autonomic nervous activity due to differences in UFR were evaluated by measuring heart rate variability (HRV) and approximate entropy (ApEn) in 35 HD patients without blood pressure variations during HD session. The subjects were divided into 3 groups, those with UFR <10 ml/h/kg; ≥10 ml/h/kg but ≤15 ml/h/kg; and >15 ml/h/kg, and Holter ECG was recorded continuously during HD session using frequency analysis of RR intervals. High frequency (HF) and low frequency (LF) spectral components are found to be representative of the parasympathetic nervous system and sympathovagal balance, respectively, with the ratio of LF to HF of HRV providing a measure of sympathetic nervous system.

RESULTS

In subjects with UFR >15 ml/h/kg, HF components were significantly lower, and LF/HF and ApEn values were significantly higher, in the latter half of an HD session than before starting HD.

CONCLUSION

Removing water from these subjects would promote sustained sympathetic nervous overactivity. These findings indicate that the UFR during HD needs to be set at ≤15 ml/h/kg.

Ultrafiltration Rate Thresholds in Maintenance Hemodialysis: An NKF-KDOQI Controversies Report

High hemodialysis ultrafiltration rate (UFR) is increasingly recognized as an important and modifiable risk factor for mortality among patients receiving maintenance hemodialysis. Recently, the Kidney Care Quality Alliance (KCQA) developed a UFR measure to assess dialysis unit care quality. The UFR measure was defined as UFR≥13mL/kg/h for patients with dialysis session length less than 240 minutes and was endorsed by the National Quality Forum as a quality measure in December 2015. Despite this, implementation of a UFR threshold remains controversial. In this NKF-KDOQI (National Kidney Foundation-Kidney Disease Outcomes Quality Initiative) Controversies Report, we discuss the concept of the UFR, which is governed by patients' interdialytic weight gain, body weight, and dialysis treatment time. We also examine the potential benefits and pitfalls of adopting a UFR threshold as a clinical performance measure and outline several aspects of UFR thresholds that require further research.

Hemodialysis-induced regional left ventricular systolic dysfunction

Introduction Hemodialysis (HD) patients are under observably elevated cardiovascular mortality. Cardiac dysfunction is closely related to death caused by cardiovascular diseases (CVD). In the general population, repetitive myocardial ischemia induced left ventricular (LV) dysfunction may progress to irreversible loss of contraction step by step, and finally lead to cardiac death. In HD patients, to remove water and solute accumulated from 48 or 72 hours of interdialysis period in a 4-hour HD session will induce myocardial ischemia. In this study, we evaluated the prevalence and potential risk factors associated with HD-induced LV systolic dysfunction and provide some evidences for clinical strategies. Methods We recruited 31 standard HD patients for this study from Fudan University Zhongshan hospital. Echocardiography was performed predialysis, at peak stress during HD (15 minutes prior to the end of dialysis), and 30 minutes after HD. Auto functional imaging (AFI) was used to assess the incidence and persistence of HD-induced regional wall motion abnormalities (RWMAs). Blood samples were drawn to measure biochemical variables. Findings Among totally 527 segments of 31 patients, 93.54% (29/31) patients and 51.40% (276/527) segments were diagnosed as RWMAs. Higher cTnT (0.060 ± 0.030 vs. 0.048 ± 0.015 ng/mL, P = 0.023), phosphate (2.07 ± 0.50 vs. 1.49 ± 0.96 mmol/L, P = 0.001), UFR (11.00 ± 3.89 vs. 8.30 ± 2.66 mL/Kg/h, P = 0.039) and lower albumin (37.83 ± 4.48 vs. 38.38 ± 2.53 g/L, P = 0.050) were found in patients with severe RWMAs (RWMAs in more than 50% segments). After univariate and multivariate analysis, interdialytic weight gain (IDWG) was found as independent risk factor of severe RWMAs (OR = 1.047, 95%CI 1.155-4.732, P = 0.038). Discussion LV systolic dysfunction induced by HD is prevalent in conventional HD patients and should be paid attention to. Patients would benefit from better weight control during interdialytic period to reduce ultrafiltration rate.

We Restrict CRRT to Only the Most Hemodynamically Unstable Patients

From the initial version of an extended renal replacement therapy, the initiative to provide safer, more efficient means for detoxification and volume removal in comparison with intermittent renal replacement therapies (IRRT) has been evaluated. As a result, the Kidney Disease Improving Global Outcomes guidelines for acute kidney injury recommend the preferential use of continuous renal replacement therapy (CRRT) in patients who are hemodynamically unstable or who suffer from intracranial hypertension. The choice of dialysis modality is also influenced by other factors including clinical expertise, and the availability of each treatment option in individual medical centers. In the scientific community, there is an ongoing debate regarding the choice of dialysis modality. On one side, the inability of recent studies to demonstrate any mortality or renal recovery benefit for CRRT, the need for patient immobilization, and prohibitive additional costs impede widespread adoption of the method.On the other side, the physiological advantages of CRRT in detoxification and volume removal and the identified flaws related to the comparative literature regarding CRRT and IRRT fuel this debate. Fluid overload is a recognized and yet clinically underappreciated factor that increases morbidity and mortality in the intensive care unit (ICU). Continuous renal replacement therapy has a distinct advantage over IRRT in achieving euvolemia and thus the potential for improving outcomes in all patients in the ICU setting in which extensive fluid administration is often obligatory. With this in mind, perhaps CRRT should not be restricted to only those patients in whom their hemodynamic status requires it. This article reviews the current literature and the myths that may influence the selection of one mode of therapy over the other among patients requiring renal replacement therapy in the ICU.