Association of residual urine output with mortality, quality of life, and inflammation in incident hemodialysis patients: the Choices for Healthy Outcomes in Caring for End-Stage Renal Disease (CHOICE) Study

Focus on oliguria during renal replacement therapy

Oliguria is a clinical symptom characterized by decreased urine output, which can occur at any stage of acute kidney injury and also during renal replacement therapy. In some cases, oliguria may resolve with adjustment of blood purification dose or fluid management, while in others, it may suggest a need for further evaluation and intervention. It is important to determine the underlying cause of oliguria during renal replacement therapy and to develop an appropriate treatment plan. This review looks into the mechanisms of urine production to investigate the mechanism of oliguria during renal replacement therapy from two aspects: diminished glomerular filtration rate and tubular abnormalities. The above conditions all implying a renal oxygen supply-demand imbalance, which is the signal of worsening kidney injury. It also proposes a viable clinical pathway for the treatment and management of patients with acute kidney injury receiving renal replacement therapy.

The relationship between decline rate of residual renal function in the first year and mortality in peritoneal dialysis patients

INTRODUCTION

To assess the relationship between the rate of residual renal function (RRF) decline in the first year and all-cause and cardiovascular mortality in peritoneal dialysis (PD) patients.

METHODS

Incident PD patients were divided into two groups by the corresponding RRF decline value, when hazard ratio (HR) = 1 was found by the restricted cubic spline. The associations of rate of decline of RRF in the first year with mortality were evaluated.

RESULTS

Of 497 PD patients, 122 patients died. After adjusting for confounding factors, patients in fast-decline group had a significant increase risk of all-cause and cardiovascular mortality (HR: 1.97 and 2.09, respectively). Each 0.1-mL/min/1.73 m2 /month decrease in RRF in the first year of PD was associated with a 19% and 20% higher risk of all-cause and cardiovascular mortality, respectively.

CONCLUSIONS

Faster decline of RRF in the first year was independently associated with all-cause and cardiovascular mortality in PD patients.

A New Dosing Frontier: Retrospective Assessment of Effluent Flow Rates and Residual Renal Function Among Critically Ill Patients Receiving Continuous Renal Replacement Therapy

OBJECTIVES

In 2020, cefiderocol became the first Food and Drug Administration-approved medication with continuous renal replacement therapy (CRRT) dosing recommendations based on effluent flow rates (QE). We aimed to evaluate the magnitude and frequency of factors that may influence these recommendations, that is, QE intrapatient variability and residual renal function.

DESIGN

Retrospective observational cohort study.

SETTING

ICUs within Hartford Hospital (890-bed, acute-care hospital) in Connecticut from 2017 to 2023.

PATIENTS

Adult ICU patients receiving CRRT for greater than 72 hours.

MEASUREMENTS AND MAIN RESULTS

CRRT settings including QE and urine output (UOP) were extracted from the time of CRRT initiation (0 hr) and trends were assessed. To assess the impact on antibiotic dosing, cefiderocol doses were assigned to 0 hour, 24 hours, 48 hours, and 72 hours QE values per product label, and the proportion of antibiotic dose changes required as a result of changes in inpatient's QE was evaluated. Among the 380 ICU patients receiving CRRT for greater than 72 hours, the median (interquartile range) 0 hour QE was 2.96 (2.35-3.29) L/hr. Approximately 9 QE values were documented per patient per 24-hour window. QE changes of greater than 0.75 L/hr were observed in 21.6% of patients over the first 24 hours and in 7.9% (24-48 hr) and 5.8% (48-72 hr) of patients. Approximately 40% of patients had UOP greater than 500 mL at 24 hours post-CRRT initiation. Due to QE changes within 24 hours of CRRT initiation, a potential cefiderocol dose adjustment would have been warranted in 38% of patients (increase of 21.3%; decrease of 16.6%). QE changes were less common after 24 hours, warranting cefiderocol dose adjustments in less than 15% of patients.

CONCLUSIONS

Results highlight the temporal and variable dynamics of QE and prevalence of residual renal function. Data also demonstrate a risk of antibiotic under-dosing in the first 24 hours of CRRT initiation due to increases in QE. For antibiotics with QE-based dosing recommendations, empiric dose escalation may be warranted in the first 24 hours of CRRT initiation.

Risk Factors for Posttransplant Erythrocytosis: Parathyroid Hormone Paradox?

OBJECTIVES

Posttransplant erythrocytosis affects 8% to 26% of kidney transplant recipients. In this study, our aim was to define associations among hypercalcemia, persistent hyperparathyroidism, and posttransplant erythrocytosis. We also investigated the effects of biologic sex, age, and dialysis modality before transplant on posttransplant erythrocytosis development.

MATERIALS AND METHODS

We enrolled 247 patients [159 (64%) male and 88 (36%) female] who underwent kidney transplant between 2009 and 2018. All demographic and laboratory parameters were retrospectively analyzed as possible factors associated with posttransplant erythrocytosis.

RESULTS

Fifty-nine (24%) of total patients had posttransplant erythrocytosis. The median time to posttransplant erythrocytosis development was 16 months (range, 8-34 mo). Male sex, the use of peritoneal dialysis as maintenance renal replacement therapy before kidney transplant, and persistent hyperparathyroidism were defined as independent risk factors for posttransplant erythrocytosis development in our multivariate logistic regression analyses (odds ratio = 5.228, 3.963, and 4.109, respectively). In addition, high serum creatinine levels were associated with a lower incidence of posttransplant erythrocytosis (odds ratio = 0.253). Although significance did not remain after multivariate analysis, hypercalcemia was found to be significantly associated with posttransplant erythrocytosis in univariate analyses (odds ratio = 1.768). In subgroup analyses, where only male patients were evaluated, persistent hyperparathyroidism and peritoneal dialysis were found to be independent risk factors for posttransplant erythrocytosis development (odds ratio = 4.176 and 5.003).

CONCLUSIONS

Persistent hyperparathyroidism and hypercalcemia could precipitate development of posttransplant erythrocytosis. The preserved residue renal function may be associated with increased endogenous erythropoietin, which could lead to posttransplant erythrocytosis development.

Dialysis for older adults: why should the targets be different?

The number of patients aged > 75-years treated by dialysis continues to increase, particularly in developed countries. Haemodialysis is a well-established treatment with national and international clinical guidelines designed to provide patients with optimal treatment. However, these were developed when the dialysis population was younger, and less co-morbid. This change in patient demographics questions whether these guideline targets still apply to older patients. More patients now start dialysis with residual kidney function and could benefit from a less frequent dialysis schedule. Older patients have a lower thirst drive, so lower interdialytic gains, reduced appetite, muscle mass and physical activity would potentially allow starting dialysis with less frequent sessions a practical option. Similarly, patients with residual kidney function and lower metabolic activity may not need to meet current dialyser Kt/Vurea clearance targets to remain healthy. Instead, some elderly patients may be at risk of malnutrition and might need liberalisation of the low salt, potassium and phosphate dietary restrictions, or even additional supplements to ensure adequate protein intake. Although a fistula is the preferred vascular access, a forearm fistula may not be an option due to vascular disease, while a brachial fistula can potentially compromise cardiovascular reserve, so a dialysis catheter becomes the de facto access, especially in patients with limited life expectancy. Thus, clinical guideline targets designed for a younger less co-morbid dialysis population may not be equally applicable to the older patient initiating dialysis, and so a more individualised approach to dialysis prescription and vascular access is required.

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.

Association Between First Post-operative Day Urine Output Following Kidney Transplantation and Short-Term and Long-Term Outcomes: A Retrospective Cohort Study

Background

The relationship between post-operative urine output (UO) following kidney transplantation and long-term graft function has not been well described.

Objective

In this study, we examined the association between decreased UO on post-operative day 1 (POD1) and post-transplant outcomes.

Design

This is a retrospective cohort study.

Setting

Atlantic Canada.

Patients

Patients from the 4 Atlantic Canadian provinces (Nova Scotia, New Brunswick, Newfoundland, and Prince Edward Island) who received a live or deceased donor kidney transplant from 2006 through 2019 through the multiorgan transplant program at the Queen Elizabeth II Health Sciences Centre (QEII) hospital in Halifax, Nova Scotia.

Measurements

Using multivariable Cox proportional hazards models, we assessed the association of low POD1 UO (defined as ≤1000 mL) with death-censored graft loss (DCGL). In secondary analyses, we used adjusted logistic regression or Cox models as appropriate to assess the impact of UO on delayed graft function (DGF), prolonged length of stay (greater than the median for the entire cohort), and death.

Results

Of the 991 patients included, 151 (15.2%) had a UO ≤1000 mL on POD1. Low UO was independently associated with DCGL (hazard ratio [HR] = 4.00, 95% confidence interval [CI] = 95% CI = 1.55-10.32), DGF (odds ratio [OR] = 45.25, 95% CI = 23.00-89.02), and prolonged length of stay (OR = 5.06, 95% CI = 2.95-8.69), but not death (HR = 0.81, 95% CI = 0.31-2.09).

Limitations

This was a single-center, retrospective, observational study and therefore has inherent limitations of generalizability, data collection, and residual confounding.

Conclusions

Overall, reduced post-operative UO following kidney transplantation is associated with an increased risk of DCGL, DGF, and prolonged hospital length of stay.

Comparison of mortality according to baseline, first year, and mean albumin levels in peritoneal dialysis: a retrospective study

BACKGROUND

The relationship between hypoalbuminemia in peritoneal dialysis (PD) and mortality, risk of peritonitis, and decreased residual renal function (RRF) is known. However, we have not encountered a comprehensive study on which of the mean albumin values, at the beginning of peritoneal dialysis, in the first year, and during the peritoneal dialysis period, provide more predictive predictions regarding mortality, peritonitis risk, and RRF reduction.

METHODS

A total of 407 PD patients in whom PD was initiated and followed up and PD was terminated were included in the study. Albumin levels, peritonitis, and RRF at the beginning of PD and at 3-month periods during PD were recorded.

RESULTS

In the evaluation of the patients, there was a significant relationship between mean, first-year albumin values in RRF loss (p = 0.001, p = 0.006, respectively) and peritonitis (p < 0.001), but no significant correlation was found with baseline albumin values (p = 0.213, p = 0.137, respectively). In the comparison of mortality ROC analysis of PD patients, a significant correlation was found with mortality at baseline, first year, and mean albumin values (p < 0.001). However, in the multivariate Cox regression analysis, it was determined that there was a more significant relationship between first-year albumin and mean albumin values compared to baseline albumin values (HR 0.918 [95% CI 0.302-0.528] (p < 0.001)), (HR 1.161 [95% CI 0.229-0.429] (p < 0.001)), (HR 0.081 [95% CI 0.718-1.184] (p = 0.525)).

CONCLUSIONS

In conclusion, mean and first-year mean albumin levels provide more determinative predictions for mortality, risk of peritonitis, and maintenance of residual renal functions in peritoneal dialysis patients compared to baseline albumin.

Influencing factors for residual kidney function in incident peritoneal dialysis patients: a systematic review and meta-analysis

BACKGROUND

Residual kidney function (RKF) impacts patients' survival rate and quality of life when undergoing peritoneal dialysis (PD). This meta-analysis was conducted to systematically identify risk and protective factors associated with RKF decline and loss.

METHODS

We searched three English and one Chinese databases from inception to January 31, 2023, for cohort and cross-sectional studies exploring factors associated with RKF decline or loss. The random effects model was employed to aggregate risk estimates and 95% confidence intervals (CIs) from multivariate analysis. Sensitivity and subgroup analyses were performed to explore the heterogeneity among the studies.

RESULTS

Twenty-seven studies comprising 13549 individuals and 14 factors were included in the meta-analysis. Based on the meta-analysis results, risk factors involving male gender (hazard ratio (HR) 1.689, 95%CI 1.385-2.061), greater body mass index (BMI) (odds ratio (OR) 1.081, 95% confidence interval (CI) 1.029-1.135), higher systolic blood pressure (SBP) (HR 1.014, 95%CI 1.005-1.024), diabetes mellitus (DM) (HRRKF loss 1.873, 95%CI 1.475-2.378), DM (ORRKF decline 1.906, 95%CI 1.262-2.879), peritonitis (relative ratio (RR) 2.291, 95%CI 1.633-3.213), proteinuria (OR 1.223, 95%CI 1.117-1.338), and elevated serum phosphorus (RR 2.655, 95%CI 1.679-4.201) significantly contributed to the risk of RKF decline and loss in PD patients. Conversely, older age (HR 0.968, 95%CI 0.956-0.981), higher serum albumin (OR 0.834, 95%CI 0.720-0.966), weekly Kt/V urea (HR 0.414, 95%CI 0.248-0.690), baseline urine volume (UV) (HR 0.791, 95%CI 0.639-0.979), baseline RKF (HR 0.795, 95%CI 0.739-0.857) exhibited protective effects. However, diuretics use, automatic peritoneal dialysis (APD) modality and baseline RKF did not significantly impact RKF decline.

CONCLUSIONS

Patients with male gender, greater BMI, higher SBP, DM, peritonitis, proteinuria, and elevated serum phosphorus might have a higher risk of RKF decline and loss. In contrast, older age, higher serum albumin, weekly Kt/V urea, baseline UV, and baseline RKF might protect against RKF deterioration.

Benefits of Preserving Residual Urine Output in Patients Undergoing Maintenance Haemodialysis

Introduction

Chronic kidney disease is a widespread medical problem that leads to higher morbidity, mortality, and a decrease in the overall well-being of the general population. This is especially expressed in patients with end-stage renal disease (ESRD) undergoing maintenance haemodialysis. Several variables could be used to evaluate those patients' well-being and mortality risk. One of them is the presence of residual urine output.

Materials and Methods

The study was conducted on 485 patients treated with maintenance haemodialysis. After enrollment in the study, which consisted of medical history, physical examination, hydration assessment, and blood sampling, each patient was followed up for 24 months. We used residual urine output (RUO) as a measure of residual renal function (RRF). The entire cohort was divided into 4 subgroups based on the daily urinary output (<=100mL per day, >100mL to <=500mL, >500mL to <=1000mL and >1000mL).

Results

The data show that the mortality rate was significantly higher in groups with lower RUO, which was caused mainly by cardiovascular events. Also, patients with higher RUO achieved better sodium, potassium, calcium, and phosphate balance. They were also less prone to overhydration and had a better nutritional status. Preserved RRF also had a positive impact on markers of cardiovascular damage, such as NT-proBNP as well as TnT.

Conclusion

In conclusion, preserving residual urine output in ESRD patients undergoing maintenance haemodialysis is invaluable in reducing their morbidity and mortality rates and enhancing other favourable parameters of those patients.

Residual Kidney Function and Cause-Specific Mortality Among Incident Hemodialysis Patients

Introduction

The survival benefit of residual kidney function (RKF) in patients on hemodialysis is presumably due to enhanced fluid management and solute clearance. However, data are lacking on the association of renal urea clearance (CLurea) with specific causes of death.

Methods

We conducted a longitudinal cohort study of 39,623 adults initiating thrice-weekly in-center hemodialysis from 2007 to 2011 and had data on renal CLurea and urine volume. Multivariable cause-specific proportional hazards model was used to examine the associations between baseline RKF and cause-specific mortality, including sudden cardiac death (SCD), non-SCD cardiovascular death (CVD), and non-CVD. Restricted cubic splines were fitted for change in RKF over 6 months after initiating hemodialysis.

Results

Among 39,623 patients with data on baseline renal CLurea and urine volume, there was a significant trend toward a higher mortality risk across lower RKF levels, irrespective of cause of death in a case-mix adjustment model (Ptrend < 0.05). Adjustment for ultrafiltration rate (UFR) slightly attenuated the association between low renal CLurea and high cause-specific mortality, whereas adjustment for highest potassium did not have substantial effect. Among 12,169 patients with data on change in RKF, a 6-month decline in renal CLurea showed graded associations with SCD, non-SCD CVD, and non-CVD risk, whereas the graded associations between faster 6-month decline in urine output and higher death risk were clear only for SCD and non-CVD.

Conclusion

Lower RKF and loss of RKF were associated with higher cause-specific mortality among patients initiating thrice-weekly in-center hemodialysis.

A Review of Residual Kidney Function in Peritoneal Dialysis Patients

Residual kidney function (RKF) has been associated with better survival, less morbidity, and improved quality of life in peritoneal dialysis (PD) patients. Since higher peritoneal clearance does not lead to better outcomes, more emphasis should be put on preserving kidney function. Many other benefits have been reported, including better volume and blood pressure control, better nutritional status, lower rates of PD peritonitis, preserved erythropoietin and vitamin D production, middle molecule clearance, lower Left Ventricular Hypertrophy, and better serum phosphate level. The most practical method of assessing RKF is the mean of 24-h urinary urea and creatinine clearance. Incremental PD prescription is an ideal option to supplement RKF in PD patients, which also offers more flexibility to the patient and, possibly, improved adherence. Angiotensin converting enzyme inhibitors and angiotensin receptor blockers should be used when possible in PD patients to preserve RKF. Loop diuretics are underutilized in PD patients despite providing an additional means of maintaining fluid balance and reducing the need for higher glucose-containing PD solutions. In this paper, we outline the importance of RKF in PD patients and the different strategies for its preservation.

Relationship between Residual Urine Output and Type of Dialysis with FGF23 Levels

Several studies investigated the role of fibroblast growth factor 23 (FGF23) in the regulation of renal phosphate excretion in chronic kidney disease (CKD). However, patients with residual urine output (UO) seem to control their serum phosphorus levels better. Our aim was to determine whether FGF23 levels are influenced by dialysis modality and UO. We performed a cross-sectional study in hemodialysis (HD) and peritoneal dialysis (PD) patients. The C-terminal FGF23 (cFGF23) levels were determined in plasma with a two-site enzyme-linked immunosorbent assay. The UO collection referred to an mL/day measurement. All p values were two-sided, and the statistical significance was set at p < 0.05. We enrolled 133 patients (58 HD, 75 PD, UO 70%). The median cFGF23 was significantly higher in HD vs. PD patients (p = 0.0017) and not significantly higher in patients without UO (p = 0.12). We found a negative correlation between cFGF23 and the UO volume (p = 0.0250), but the correlation was not significant when considering the type of dialysis treatment. Phosphorus (ß = 0.21677; p = 0.0007), type of dialysis (ß = −0.68392; p = 0.0003), and creatinine (ß = 0.08130; p = 0.0133) were significant and independent predictors of cFGF23 levels. In conclusion, cFGF23 was significantly higher in HD than in PD patients. We found a significant negative correlation between cFGF23 and the residual UO volume, but the correlation was not significant considering the type of dialysis. Our study reveals that dialysis modality is an independent predictor of FGF23 levels. In particular, PD is associated with lower FGF23 levels than HD.

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

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

On the importance of the interplay of residual renal function with clinical outcomes in end-stage kidney disease

Chronic kidney disease (CKD) is one of the most important public health concerns of the century, and is associated with high rates of morbidity, mortality and social costs. CKD evolving towards end-stage kidney disease (ESKD) is on the rise resulting in a greater number of patients requiring peritoneal dialysis (PD) and hemodialysis (HD). The aim of this manuscript is to review the current literature on the interplay of residual renal function (RRF) with clinical outcomes in ESKD. The persistence of RRF is one of the most important predictors of decreased morbidity, mortality, and better quality of life in both PD and HD patients. RRF contributes to the well-being of ESKD patients through various mechanisms including higher clearance of solutes, maintenance of fluid balance, removal of uremic toxins and control of electrolytes. Furthermore, RRF has beneficial effects on inflammation, anemia, malnutrition, diabetes mellitus, obesity, changes in the microbiota, and cardiac diseases. Several strategies have been proposed to preserve RRF, such as blockade of the renin-angiotensin-aldosterone system, better blood pressure control, incremental PD and HD. Several clinical trials investigating the issue of preservation of RRF are ongoing. They are needed to broaden our understanding of the interplay of RRF with clinical outcomes in ESKD.

The efficacy and safety of Sacubitril/Valsartan on pulmonary hypertension in hemodialysis patients

Background

Pulmonary hypertension (PH) is a common complication of end-stage renal disease which is associated with adverse outcomes including all-cause mortality and cardiovascular events. Recent studies have demonstrated that Sacubitril/Valsartan (Sac/Val) as an enkephalinase inhibitor and angiotensin II receptor blocker could reduce pulmonary artery systolic pressure (PASP) and improve the prognosis of patients with heart failure. However, whether Sac/Val is effective in hemodialysis (HD) patients with PH is essentially unknown. In this retrospective study, we aimed to evaluate the efficacy and safety of Sac/Val in the treatment of PH in HD patients.

Methods

A total of 122 HD patients with PH were divided into Sac/Val group (n = 71) and ARBs group (n = 51) based on the treatment regimen. The PASP, other cardiac parameters measured by echocardiography, and cardiac biomarkers including N-terminal fragment of BNP (NT-proBNP) and cardiac troponin I (cTnI) were observed at baseline and 3 months after treatment.

Results

There were no significant differences in the baseline characteristics between the two groups. PASP decreased significantly from 45(38, 54) to 28(21, 40) mmHg in Sac/Val group (p &lt; 0.001). PASP reduced from 41(37, 51) to 34(27, 44) mmHg in ARBs group (p &lt; 0.001), and the decrease was more pronounced in the Sac/Val group (p &lt; 0.001). In addition, improvements in the right atrial diameter (RAD), left ventricular diameter (LVD), left ventricular posterior wall thickness (LVPWT), left atrial diameter (LAD), pulmonary artery diameter (PAD), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), left ventricular ejection fraction (LVEF), and fractional shortening (FS) were found in Sac/Val group (ps &lt; 0.05). After 3 months, LVD, LAD, LVEDV, LVESV, LVEF, SV, and PASP were significantly improved in Sac/Val group compared with ARBs group (ps &lt;0.05). Significant reduction in NT-proBNP [35,000 (15,000, 70,000) pg/ml vs. 7,042 (3,126, 29,060) pg/ml, p &lt; 0.001] and cTnI [0.056(0.031, 0.085) ng/ml vs. 0.036 (0.012, 0.056) ng/ml, p &lt; 0.001) were observed in Sac/Val group. No significant differences were observed in adverse events between the two groups (ps &gt; 0.05).

Conclusion

Sac/Val seems to be an efficacious regimen in PH with favorable safety and has huge prospects for treating PH in HD patients.

Urine volume as an estimator of residual renal clearance and urinary removal of solutes in patients undergoing peritoneal dialysis

In non-anuric patients undergoing peritoneal dialysis (PD), residual kidney function (RKF) is a main contributor to fluid and solute removal and an independent predictor of survival. We investigated if urine volume could be used to estimate renal clearances and removal of urea, creatinine, and phosphorus in PD patients. The observational, cross-sectional study included 93 non-anuric prevalent PD patients undergoing continuous ambulatory PD (CAPD; n = 34) or automated PD (APD; n = 59). Concentrations of urea, creatinine and phosphorus in serum and in 24-h collections of urine volume were measured to calculate weekly residual renal clearance (L/week) and removed solute mass (g/week). Median [interquartile range], 24-h urine output was 560 [330-950] mL and measured GFR (the mean of creatinine and urea clearances) was 3.24 [1.47-5.67] mL/min. For urea, creatinine and phosphorus, residual renal clearance was 20.60 [11.49-35.79], 43.02 [19.13-75.48] and 17.50 [8.34-33.58] L/week, respectively, with no significant differences between CAPD and APD. Urine volume correlated positively with removed solute masses (rho = 0.82, 0.67 and 0.74) and with weekly residual renal clearances (rho = 0.77, 0.62 and 0.72 for urea, creatinine, and phosphorus, respectively, all p < 0.001). Residual renal clearances and urinary mass removal rates for urea, creatinine, and phosphorus correlate strongly with 24-h urine volume suggesting that urine volume could serve as an estimator of typical values of residual solute removal indices in PD patients.

Patient-reported outcomes in a pilot clinical trial of twice-weekly hemodialysis start with adjuvant pharmacotherapy and transition to thrice-weekly hemodialysis vs conventional hemodialysis

Background

Physical and emotional symptoms are prevalent in patients with kidney-dysfunction requiring dialysis (KDRD) and the rigors of thrice-weekly hemodialysis (HD) may contribute to deteriorated health-related quality of life. Less intensive HD schedules might be associated with lower symptom and/or emotional burden.

Methods

The TWOPLUS Pilot study was an individually-randomized trial conducted at 14 dialysis units, with the primary goal to assess feasibility and safety. Patients with incident KDRD and residual kidney function were assigned to incremental HD start (twice-weekly HD for 6 weeks followed by thrice-weekly HD) vs conventional HD (thrice-weekly HD). In exploratory analyses, we compared the two treatment groups with respect to three patient-reported outcomes measures. We analyzed the change from baseline in the score on Dialysis Symptom Index (DSI, range 0–150), Generalized Anxiety Disorder-7 (GAD-7, range 0–21), and Patient Health Questionnaire-9 (PHQ-9, range 0–27) at 6 (n = 20 in each treatment group) and 12 weeks (n = 21); with lower scores denoting lower symptom burden. Analyses were adjusted for age, race, gender, baseline urine volume, diabetes mellitus, and malignancy. Participants’ views on the intervention were sought using a Patient Feedback Questionnaire (n = 14 in incremental and n = 15 in conventional group).

Results

The change from baseline to week 6 in estimated mean score (standard error; P value) in the incremental and conventional group was − 9.7 (4.8; P = 0.05) and − 13.8 (5.0; P = 0.009) for DSI; − 1.9 (1.0; P = 0.07) and − 1.5 (1.4; P = 0.31) for GAD-7; and − 2.5 (1.1; P = 0.03) and − 3.5 (1.5; P = 0.02) for PHQ-9, respectively. Corresponding changes from week 6 to week 12 were − 3.1 (3.2; P = 0.34) and − 2.4 (5.5; P = 0.67) in DSI score; 0.5 (0.6; P = 0.46) and 0.1 (0.6; P = 0.87) in GAD-7 score; and − 0.3 (0.6; P = 0.70) and − 0.5 (0.6; P = 0.47) in PHQ-9 score, respectively. Majority of respondents felt their healthcare was not jeopardized and expressed their motivation for study participation was to help advance the care of patients with KDRD.

Conclusions

This study suggests a possible mitigating effect of twice-weekly HD start on symptoms of anxiety and depression at transition from pre-dialysis to KDRD. Larger clinical trials are required to rigorously test clinically-matched incrementally-prescribed HD across diverse organizations and patient populations.

Trial registration

Registered at ClinicalTrials.gov with study identifier NCT03740048, registration date 14/11/2018.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02946-w.

Twice-Weekly Hemodialysis With Adjuvant Pharmacotherapy and Transition to Thrice-Weekly Hemodialysis: A Pilot Study

RATIONALE & OBJECTIVE

Thrice-weekly hemodialysis (HD) is the most common treatment modality for kidney failure in the United States. We conducted a pilot study to assess the feasibility and safety of incremental-start HD in patients beginning maintenance HD.

STUDY DESIGN

Pilot study.

SETTING & PARTICIPANTS

Adults with estimated glomerular filtration rate (eGFR) ≥5 mL/min/1.73 m² and urine volume ≥500 mL/d beginning maintenance HD at 14 outpatient dialysis units.

EXPOSURE

Randomized allocation (1:1 ratio) to twice-weekly HD and adjuvant pharmacologic therapy for 6 weeks followed by thrice-weekly HD (incremental HD group) or thrice-weekly HD (conventional HD group).

OUTCOME

The primary outcome was feasibility. Secondary outcomes included changes in urine volume and solute clearance.

RESULTS

Of 77 patients invited to participate, 51 consented to do so, representing 66% of eligible patients. We randomized 23 patients to the incremental HD group and 25 patients to the conventional HD group. Protocol-based loop diuretics, sodium bicarbonate, and patiromer were prescribed to 100%, 39%, and 17% of patients on twice-weekly HD, respectively. At a mean follow-up of 281.9 days, participant adherence was 96% to the HD schedule (22 of 23 and 24 of 25 in the incremental and conventional groups, respectively) and 100% in both groups to serial timed urine collection. The incidence rate ratio for all-cause hospitalization was 0.31 (95% CI, 0.08-1.17); and 7 deaths were recorded (1 in the incremental and 6 in the conventional group). At week 24, the incremental HD group had lower declines in urine volume (a difference of 51.0 [95% CI, -0.7 to 102.8] percentage points) and in the averaged urea and creatinine clearances (a difference of 57.9 [95% CI, -22.6 to 138.4] percentage points).

LIMITATIONS

Small sample size, time-limited twice-weekly HD.

CONCLUSIONS

It is feasible to enroll patients beginning maintenance HD into a randomized study of incremental-start HD with adjuvant pharmacotherapy who adhere to the study protocol during follow-up. Larger multicenter clinical trials are indicated to determine the efficacy and safety of incremental HD with longer twice-weekly HD periods.

FUNDING

Funding was provided by Vifor Inc.

TRIAL REGISTRATION

Registered at ClinicalTrials.gov, identifier NCT03740048.

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.

Physical Resilience Phenotype Trajectories in Incident Hemodialysis: Characterization and Mortality Risk Assessment

Introduction

Methods

Results

Conclusion

Incremental Hemodialysis: What We Know so Far

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

Efficacy of Roxadustat on anemia and residual renal function in patients new to peritoneal dialysis

Background

Both early correction of anemia and preserving residual renal function (RRF) are reported to improve patient survival. The aim of this study was to explore the efficacy and safety of Roxadustat for treatment of renal anemia in patients new to peritoneal dialysis (PD) and to assess its impact on RRF.

Methods

A retrospective analysis was performed on 60 initial peritoneal dialysis (PD) patients with renal anemia. Twenty-eight cases were treated with Roxadustat (Roxadustat group) and 32 with recombinant human erythropoietin (control group). Clinical characteristics, hemoglobin (Hb), C-reactive protein, blood lipids, iron metabolism, dialysis adequacy and RRF of the two groups were evaluated and adverse events were recorded. All patients were followed up for at least 40 weeks.

Results

After 40 weeks of treatment, mean Hb levels were significantly higher from baseline values in both groups, the mean Hb change in Roxadustat group was higher than control group (3.46 ± 1.59 g/dL vs. 2.28 ± 2.27 g/dL, p < 0.05). At 40 weeks, 92.9% patients met the target level of Hb in Roxadustat group and 84.4% in control group. Total iron binding was higher and ferritin was lower in Roxadustat group from baseline values and Roxadustat-induced Hb increases were independent of baseline C-reactive protein levels and history of rhuEPO administration. RRF decreased over time in both groups, the mean RRF change was lower in Roxadustat group than control group (1.15 ± 1.66 mL/min/1.73 m² vs. 2.31 ± 1.46 mL/min/1.73 m², p < 0.01). Compared with control group, patients in Roxadustat group had higher levels of total iron binding, 24 h urine volume, total weekly Ccr, and lower systolic pressure, ferritin, C-reactive protein, total cholesterol, LDL. No serious adverse reactions occurred in either group.

Conclusion

In patients new to PD, Roxadustat effectively and safely improved renal anemia and delay the decline of RRF.

The association between office blood pressure and fluid status using bioimpedance spectroscopy in stable continuous ambulatory peritoneal dialysis patients

Background

Hypertension is common in continuous ambulatory peritoneal dialysis (CAPD) patients. It remains to be determined the extent to which fluid overload contributes to uncontrolled blood pressure (BP) in this population. The aim was to determine the association between fluid status as measured using bioimpedance spectroscopy (BIS) and BP in CAPD patients.

Methods

A cross-sectional study was performed involving 50 stable CAPD patients at a single center in Cape Town, South Africa. All participants were known to have hypertension and were divided into two groups based on office BP measurements: an uncontrolled BP group (systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg) and a controlled BP group. Fluid status was determined using BIS (Body Composition Monitor®, Fresenius Medical Care, Bad Homburg, Germany).

Results

There was a statistically significant difference in overhydration (OH) between the uncontrolled BP group and the controlled BP group (3.0 ± 2.3 L vs. 1.4 ± 1.6 L, respectively, P = 0.01). The uncontrolled BP group was older (37.7 ± 9.5 years vs. 32.0 ± 8.0 years, P = 0.04) and had a shorter dialysis vintage (15 [IQR, 7–22] months vs. 31 [IQR, 12–39] months, P = 0.02). Significant correlations were found between OH and the extracellular water (ECW) (r = 0.557, P < 0.01) and ECW to total body water (TBW) ratio (r = 0.474, P < 0.01). Mixed ancestry, presence of residual kidney function, ECW, and ECW to TBW ratio were identified as predictors of OH on multivariable linear regression.

Conclusions

We found that stable CAPD patients with uncontrolled BP had higher OH compared to patients whose BP was controlled.

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.

Smoothing transition to dialysis to improve early outcomes after dialysis initiation among old and frail adults-a narrative review

The number of patients ≥65 years of age suffering from advanced chronic kidney disease and transitioning to end-stage kidney disease (ESKD) is increasing. However, elderly patients often have poor outcomes once haemodialysis is initiated, including high mortality within the first year as well as fast cognitive and functional decline and diminished quality of life. The question is how we can smooth this transition to ESKD in older patients who also exhibit much higher proportions of frailty when compared with community-dwelling non-dialysis older adults and who are generally more vulnerable to invasive treatment such as kidney replacement therapy. To avoid early death and poor quality of life, a carefully prepared smooth transition should precede the initiation of treatment. This involves pre-dialysis physical and educational care, as well as mental and psychosocial preparedness of the patient to enable an informed and shared decision about the individual choice of treatment modality. Communication between a healthcare professional and patient plays a pivotal role but can be challenging given the high rate of cognitive impairment in this particular population. In order to practise patient-centred care, adapting treatment tailored to the individual patient should include comprehensive conservative care. However, structured treatment pathways including multidisciplinary teams for such conservative care are still rare and may be difficult to establish outside of large cities. Generally, geriatric nephrology misses data on the comparative effectiveness of different treatment modalities in this population of old and very old age on which to base recommendations and decisions.

Dietary Potassium Intake and All-Cause Mortality in Adults Treated with Hemodialysis

BACKGROUND AND OBJECTIVES

Dietary potassium restriction in people receiving maintenance hemodialysis is standard practice and is recommended in guidelines, despite a lack of evidence. We aimed to assess the association between dietary potassium intake and mortality and whether hyperkalemia mediates this association.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A total of 8043 adults undergoing maintenance hemodialysis in Europe and South America were included in the DIETary intake, death and hospitalization in adults with end-stage kidney disease treated with HemoDialysis (DIET-HD) study. We measured baseline potassium intake from the Global Allergy and Asthma European Network food frequency questionnaire and performed time-to-event and mediation analyses.

RESULTS

The median potassium intake at baseline was 3.5 (interquartile range, 2.5-5.0) g/d. During a median follow-up of 4.0 years (25,890 person-years), we observed 2921 (36%) deaths. After adjusting for baseline characteristics, including cardiac disease and food groups, dietary potassium intake was not associated with all-cause mortality (per 1 g/d higher dietary potassium intake: hazard ratio, 1.00; 95% confidence interval [95% CI], 0.95 to 1.05). A mediation analysis showed no association of potassium intake with mortality, either through or independent of serum potassium (hazard ratio, 1.00; 95% CI, 1.00 to 1.00 and hazard ratio, 1.01; 95% CI, 0.96 to 1.06, respectively). Potassium intake was not significantly associated with serum levels (0.03; 95% CI, -0.01 to 0.07 mEq/L per 1 g/d higher dietary potassium intake) or the prevalence of hyperkalemia (≥6.0 mEq/L) at baseline (odds ratio, 1.11; 95% CI, 0.89 to 1.37 per 1 g/d higher dietary potassium intake). Hyperkalemia was associated with cardiovascular death (hazard ratio, 1.23; 95% CI, 1.03 to 1.48).

CONCLUSIONS

Higher dietary intake of potassium is not associated with hyperkalemia or death in patients treated with hemodialysis.

Benefits of Incremental Hemodialysis Seen in a Historical Cohort Study

Purpose

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

Patients and Methods

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

Results

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

Conclusion

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

YouTube as a platform for knowledge and awareness of peritoneal dialysis: A content analysis

BACKGROUND

One of the main barriers to choosing peritoneal dialysis (PD) is the lack of awareness and PD knowledge. There is an increasing trend in the use of the internet as a search tool for health-related information. This study aims to determine how useful YouTube videos are to get information about PD.

METHODS

YouTube videos were evaluated independently by two nephrologists. The videos' quality was assessed with DISCERN scoring system, global quality score (GQS) and the Journal of the American Medical Association (JAMA) scoring system. We determined the quartile (Q) of the videos as follows: most reliable top 25% videos Q1 and others Q2-4.

RESULTS

A total of 295 videos were evaluated. University or society-sourced videos made up 15% (n = 43) of all videos, and healthcare providers were the primary target audience compared to patients (p < 0.001). JAMA, GQS and DISCERN scores were significantly higher for the videos that were targeted healthcare providers compared to the patients (p < 0.001, for all). A total of 34% of the videos in Q1 were obtained from the university or society. Nevertheless, only 17% of the videos prepared for the patients were among the Q1. A small number of videos mentioned that PD maintains the residual kidney function (RKF) longer compared to haemodialysis.

CONCLUSIONS

Universities and societies should upload videos to provide easy-to-understand information on PD. Also, the important benefits of PD, like the preservation of RKF, should be further highlighted in these videos. It may increase the PD penetrance by increasing patients' awareness.

Protection of Residual Renal Function and Nutritional Treatment: First Step Strategy for Reduction of Uremic Toxins in End-Stage Kidney Disease Patients

The retention of uremic toxins and their pathological effects occurs in the advanced phases of chronic kidney disease (CKD), mainly in stage 5, when the implementation of conventional thrice-weekly hemodialysis is the prevalent and life-saving treatment. However, the start of hemodialysis is associated with both an acceleration of the loss of residual kidney function (RKF) and the shift to an increased intake of proteins, which are precursors of uremic toxins. In this phase, hemodialysis treatment is the only way to remove toxins from the body, but it can be largely inefficient in the case of high molecular weight and/or protein-bound molecules. Instead, even very low levels of RKF are crucial for uremic toxins excretion, which in most cases are protein-derived waste products generated by the intestinal microbiota. Protection of RKF can be obtained even in patients with end-stage kidney disease (ESKD) by a gradual and soft shift to kidney replacement therapy (KRT), for example by combining a once-a-week hemodialysis program with a low or very low-protein diet on the extra-dialysis days. This approach could represent a tailored strategy aimed at limiting the retention of both inorganic and organic toxins. In this paper, we discuss the combination of upstream (i.e., reduced production) and downstream (i.e., increased removal) strategies to reduce the concentration of uremic toxins in patients with ESKD during the transition phase from pure conservative management to full hemodialysis treatment.

Paraoxonase 1 concerning dyslipidaemia, cardiovascular diseases, and mortality in haemodialysis patients

Paraoxonase 1 (PON1) is known for preventing atherosclerosis through lipid-modifying features, antioxidant activity, anti-inflammatory, anti-apoptosis, anti-thrombosis, and anti-adhesion properties. Uremic patients requiring haemodialysis (HD) are especially prone to atherosclerosis and its complications. We analysed the PON1 gene (PON1) polymorphisms and serum PON1 (paraoxonase) activity concerning dyslipidaemia and related cardiovascular diseases and mortality to show how they associate under uremic conditions modified by maintenance HD treatment. The rs662 AA + AG (OR 1.76, 95%CI 1.10-2.80, P = 0.018), rs854560 TT (OR 1.48, 95%CI 1.04-2.11, P = 0.031), and rs854560 AT + TT (OR 1.28, 95%CI 1.01-1.63, P = 0.040) contributed to the prevalence of atherogenic dyslipidaemia diagnosed by the triglyceride (TG)/HDL-cholesterol ratio ≥ 3.8. The normalized serum PON1 activity positively correlated with atherogenic dyslipidaemia (ẞ 0.67 ± 0.25, P = 0.008). The PON1 rs854560 allele T was involved in the higher prevalence of ischemic cerebral stroke (OR 1.38, 1.02-1.85, P = 0.034). The PON1 rs705379 TT genotype contributed to cardiovascular (HR 1.27, 95% CI 1.03-1.57, P = 0.025) and cardiac (HR 1.34, 95% CI 1.05-1.71, P = 0.018) mortality. All P-values were obtained in multiple regression analyses, including clinical variables. Multifaceted associations of PON1 with dyslipidaemia, ischemic cerebral stroke, and cardiovascular mortality in HD patients provide arguments for the consideration of PON1 and its protein product as therapeutic targets in the prevention of atherosclerosis and its complications in uremic patients.

Complications and challenges of home hemodialysis: A historical review

Home hemodialysis (HHD) has evolved as a preferred and safe kidney replacement modality over the past six decades. Despite advances in technological aspects of HHD, potential complications still pose a challenge to health care givers, patients, and their families. In this narrative review, we describe vascular access and cannulation, anticoagulation, nutritional, residual kidney function, psychosocial, technique failure, and machine/procedural-related complications. Addressing these problems is essential for favorable patient outcomes.

Novel options for failing allograft in kidney transplanted patients to avoid or defer dialysis therapy

PURPOSE OF REVIEW

Despite improvement in short-term renal allograft survival in recent years, renal transplant recipients (RTR) have poorer long-term allograft outcomes. Allograft function slowly declines with periods of stable function similar to natural progression of chronic kidney disease in nontransplant population. Nearly all RTR transitions to failing renal allograft (FRG) period and require transition to dialysis. Conservative chronic kidney disease management before transition to end-stage renal disease is an increasingly important topic; however, there is limited data in RTR regarding how to delay dialysis initiation with conservative management.

RECENT FINDINGS

Since immunological and nonimmunological factors unique to RTR contribute to decline in allograft function, therapies to slow progression of FRG should take both sets of factors into account. Renal replacement therapy either incremental dialysis or rekidney transplantation should be explored. This required taking benefits and risks of continuing immunosuppressive medications into account when allograft nephrectomy may be necessary.

SUMMARY

FRG may benefit from various interventions to slow progression of worsening allograft function. Until there are stronger evidence to guide interventions to preserve renal function, extrapolating evidence from nontransplant patients and clinical judgment are necessary. The goal is to provide individualized care for conservative management of RTR with FRG.

Usefulness of ABPM and bioimpedance for the treatment and control of hypertension in patients on chronic haemodialysis

INTRODUCTION

Hypertension is very common in haemodialysis (HD) patients, and is associated with increased morbidity and mortality rates. The goals of our research were to: 1. Measure blood pressure (BP) during HD sessions; 2. Study BP in between HD sessions with 44-h Ambulatory Blood Pressure Monitoring (ABPM); 3. Evaluate changes in treatment after the ABPM; 4. Perform bioimpedance spectroscopy (BIS) on all patients and, in those hyper-hydrated or hypertensive according to ABPM, assess for changes in BP after adjusting the dry weight; 5. Identify factors associated with average systolic and diastolic BP measured by ABPM.

MATERIAL AND METHODS

Prospective observational study, which included 100 patients from our dialysis unit. We measured BP before and after the HD sessions for two weeks and then, mid-week, we attached the ABPM device to the patients for 44 h. Before starting the following dialysis session, we performed BIS. A second ABPM was performed on hyper-hydrated patients and patients hypertensive according to ABPM to evaluate changes in BP values.

RESULTS

According to the ABPM, 65% of patients had daytime BP > 135/85 mmHg, 90% night-time BP > 120/70 mmHg and 76% average BP > 130/80 mmHg; 11% had a dipper pattern, 51% non-dipper and 38% riser. The average systolic and diastolic BP readings were 4.7 mmHg (3.8%) and 1.1 mmHg (1.64%) higher on the second day. The dose of antihypertensive medication had to be lowered in 6% of patients, 9% had to stop taking it, 28% needed increased doses and 17% had to add a new drug. The pre-HD diastolic BP best matched the ABPM. After performing the bioimpedance and adjusting dry weight, there was a statistically significant decrease in all BP values. The univariate analysis showed that the average systolic BP was higher in patients with a high-calcium dialysis bath, more antihypertensive drugs and higher doses of EPO. The multivariate analysis showed significant association for EPO and number of drugs (p < 0.01). The average diastolic BP was higher in younger patients and patients with lower Charlson index, lower body mass index and less diuresis, those on higher doses of EPO and non-diabetics. The linear regression study showed age (p < 0.005), body mass index (p < 0.03) and EPO (p < 0.03) as significant variables.

CONCLUSIONS

Our study shows: 1. The variability of hypertension criteria according to use of BP values from during the HD session or ABPM; 2. The variability of BP in the interdialysis period; 3. That the pre-dialysis diastolic BP best corresponds with the ABPM. 4. That the use of both BIS and ABPM improves the control of BP; 5. That the dose of EPO is the most important factor associated with hypertension in our patients.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Contribution of 'clinically negligible' residual kidney function to clearance of uremic solutes

BACKGROUND

Residual kidney function (RKF) is thought to exert beneficial effects through clearance of uremic toxins. However, the level of native kidney function where clearance becomes negligible is not known.

METHODS

We aimed to assess whether levels of nonurea solutes differed among patients with 'clinically negligible' RKF compared with those with no RKF. The hemodialysis study excluded patients with urinary urea clearance >1.5 mL/min, below which RKF was considered to be 'clinically negligible'. We measured eight nonurea solutes from 1280 patients participating in this study and calculated the relative difference in solute levels among patients with and without RKF based on measured urinary urea clearance.

RESULTS

The mean age of the participants was 57 years and 57% were female. At baseline, 34% of the included participants had clinically negligible RKF (mean 0.7 ± 0.4 mL/min) and 66% had no RKF. Seven of the eight nonurea solute levels measured were significantly lower in patients with RKF than in those without RKF, ranging from -24% [95% confidence interval (CI) -31 to -16] for hippurate, -7% (-14 to -1) for trimethylamine-N-oxide and -4% (-6 to -1) for asymmetric dimethylarginine. The effect of RKF on plasma levels was comparable or more pronounced than that achieved with a 31% higher dialysis dose (spKt/Vurea 1.7 versus 1.3). Preserved RKF at 1-year follow-up was associated with a lower risk of cardiac death and first cardiovascular event.

CONCLUSIONS

Even at very low levels, RKF is not 'negligible', as it continues to provide nonurea solute clearance. Management of patients with RKF should consider these differences.

Evaluating dialysis adequacy: Origins, evolution, and future directions

The expansion and transformation over time of dialysis therapies have been inexorably linked to the concept of adequacy. While initially the goal of dialysis was simple survival of patients until their next treatment, this changed with the publication of the National Cooperative Dialysis Study. It brought about a focus on defining adequate dialysis through measurements of the removal of small solutes, in particular urea. This spurred significant improvements in patient outcomes by standardizing therapy and providing benchmarks for each center to achieve. Over time, however, further research has found this narrow definition of adequacy to be insufficient to encompass the complexities of dialysis therapies. Factors such as residual kidney function (RKF), nutritional and volume status, and cardiovascular control all contribute to the outcomes for dialysis patients. We propose that an optimal definition of adequacy should not only focus on one factor but rather the interconnection and contribution to our patient's individual specific goals and their overall quality of life.

A faster decline of residual kidney function and erythropoietin stimulating agent hyporesponsiveness in incident hemodialysis patients

INTRODUCTION

Erythropoietin stimulating agents (ESA) hyporesposiveness has been associated with increased mortality in hemodialysis (HD) patients. However, the impact of decline of residual kidney function (RKF) on ESA hyporesposiveness has not been adequately elucidated among patients receiving HD.

METHODS

The associations of RKF decline with erythropoietin resistance index (ERI; average weekly ESA dose [units])/post-dialysis body weight [kg]/hemoglobin [g/dL]) were retrospectively examined across four strata of annual change in RKF (residual renal urea clearance [KRU] < -3.0, -3.0 to <-1.5, -1.5 to <0, ≥0 mL/min/1.73 m² per year; urinary volume < -600, -600 to<-300, -300 to <0, ≥0 mL/day per year) using logistic regression models adjusted for clinical characteristics and laboratory variables in 5239 incident HD patients in a large US dialysis organization between 1 January 2007 and 31 December 2011.

FINDINGS

The median values of the annual change in KRU and urinary volume were -1.2 (interquartile range [IQR]: -2.8 to 0.1) mL/min/1.73 m² per year and -250 (IQR: -600 to 100) mL/day per year. A faster KRU decline in the first year of HD was associated with higher odds for ESA hyporesponsiveness: KRU decline of <-3.0, -3.0 to <-1.5, and -1.5 to <0/min/1.73 m² per year were associated with adjusted odds ratios (OR) of 2.07 (95% confidence interval [CI]: 1.66-2.58), 1.54 (95%CI: 1.28-1.85), and 1.26 (95%CI: 1.07-1.49), respectively (reference: ≥0 mL/min/1.73 m² per year). These associations were consistent across strata of baseline KRU, age, sex, race, diabetes, congestive heart failure, hemoglobin, and serum albumin. Sensitivity analyses using urinary volume as another index of RKF showed consistent associations.

DISCUSSION

A faster RKF decline during the first year of dialysis was associated with ESA hyporesponsiveness and low hemoglobin levels among incident HD patients.

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

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

Usefulness of ABPM and bioimpedance for the treatment and control of hypertension in patients on chronic haemodialysis

INTRODUCTION

Hypertension is very common in haemodialysis (HD) patients, and is associated with increased morbidity and mortality rates. The goals of our research were to: 1. Measure blood pressure (BP) during HD sessions; 2. Study BP in between HD sessions with 44-hour Ambulatory Blood Pressure Monitoring (ABPM); 3. Identify differences between the BP recorded during HD and with the ABPM; 4. Evaluate changes in treatment after the ABPM; 5. Perform bioimpedance spectroscopy (BIS) on all patients and, in those hyper-hydrated or hypertensive according to ABPM, assess for changes in BP after adjusting the dry weight; 6. Identify factors associated with average systolic and diastolic BP measured by ABPM.

MATERIAL AND METHODS

Prospective observational study, which included 100 patients from our dialysis unit. We measured BP before and after the HD sessions for two weeks and then, mid-week, we attached the ABPM device to the patients for 44 hours. Before starting the following dialysis session, we performed BIS. A second ABPM was performed on hyper-hydrated patients and patients hypertensive according to ABPM to evaluate changes in BP values.

RESULTS

According to the ABPM, 65% of patients had daytime BP > 135/85 mmHg, 90% night-time BP > 120/70 mmHg and 76% average BP > 130/80 mmHg; 11% had a dipper pattern, 51% non-dipper and 38% riser. The average systolic and diastolic BP readings were 4.7 mmHg (3.8%) and 1.1 mmHg (1.64%) higher on the second day. The dose of antihypertensive medication had to be lowered in 6% of patients, 9% had to stop taking it, 28% needed increased doses and 17% had to add a new drug. The pre-HD diastolic BP best matched the ABPM. After performing the bioimpedance and adjusting dry weight, there was a statistically significant decrease in all BP values. The univariate analysis showed that the average systolic BP was higher in patients with a high-calcium dialysis bath, more antihypertensive drugs and higher doses of EPO. The multivariate analysis showed significant association for EPO and number of drugs (p < 0.01). The average diastolic BP was higher in younger patients and patients with lower Charlson index, lower body mass index and less diuresis, those on higher doses of EPO and non-diabetics. The linear regression study showed age (p < 0.005), body mass index (p < 0.03) and EPO (p < 0.03) as significant variables.

CONCLUSIONS

Our study shows: 1. The variability of hypertension criteria according to use of BP values from during the HD session or ABPM; 2. The variability of BP in the interdialysis period; 3. That the pre-dialysis diastolic BP best corresponds with the ABPM. 4. That the use of both BIS and ABPM improves the control of BP; 5. That the dose of EPO is the most important factor associated with hypertension in our patients.

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

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

Residual Urine Output and Mortality in a Prospective Hemodialysis Cohort

Introduction

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

Methods

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

Results

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

Conclusion

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

Primary causes of kidney disease and mortality in dialysis-dependent children

BACKGROUND

Congenital anomalies of the kidney and urinary tract (CAKUT) is associated with a slower progression to end-stage renal disease (ESRD) in pre-dialysis patients. However, little is known about the associated mortality risks after transitioning to dialysis.

METHODS

This retrospective cohort study included 0-21 year-old incident dialysis patients from the United States Renal Data System starting dialysis between 1995 and 2016. We examined the association of CAKUT vs. non-CAKUT with all-cause mortality, using Cox regression adjusted for case mix variables. We also examined the mortality risk associated with 14 non-CAKUT vs. CAKUT ESRD etiologies and under stratification by estimated glomerular filtration rate (eGFR).

RESULTS

Among 25,761 patients, the median (interquartile range) age was 17 (11-19) years, and 4780 (19%) had CAKUT. CAKUT was associated with lower mortality, with an adjusted hazard ratio (aHR) of 0.72 (95%CI, 0.64-0.81) (reference: non-CAKUT). In age-stratified analyses, CAKUT vs. non-CAKUT aHRs (95%CI) were 0.66 (0.54-0.80), 0.56 (0.39-0.80), 0.66 (0.50-0.86), and 0.97 (0.80-1.18) among patients < 6, 6-< 13, 13-< 18, and ≥ 18 years at dialysis initiation, respectively. Among non-CAKUT ESRD etiologies, the risk of mortality associated with primary glomerulonephritis (aHR, 0.93; 95%CI 0.80-1.09) and focal segmental glomerulosclerosis (aHR, 0.89; 95%CI, 0.75-1.04) were comparable or slightly lower compared to CAKUT, whereas most other primary causes were associated with higher mortality risk. While the CAKUT group had lower mortality risk compared to the non-CAKUT group patients with eGFR ≥5 mL/min/1.73m², CAKUT was associated with higher mortality in patients with eGFR < 5 mL/min/1.73 m².

CONCLUSIONS

CAKUT is associated with lower mortality among children < 18 years old, but showed comparable mortality with non-CAKUT among patients ≥ 18 years old. ESRD etiology should be considered in risk assessment for children initiating dialysis.

Initiating haemodialysis twice-weekly as part of an incremental programme may protect residual kidney function

BACKGROUND

Initiating twice-weekly haemodialysis (2×HD) in patients who retain significant residual kidney function (RKF) may have benefits. We aimed to determine differences between patients initiated on twice- and thrice-weekly regimes, with respect to loss of kidney function, survival and other safety parameters.

METHODS

We conducted a single-centre retrospective study of patients initiating dialysis with a residual urea clearance (KRU) of ≥3 mL/min, over a 20-year period. Patients who had 2×HD for ≥3 months during the 12 months following initiation of 2×HD were identified for comparison with those dialysed thrice-weekly (3×HD).

RESULTS

The 2×HD group consisted of 154 patients, and the 3×HD group 411 patients. The 2×HD patients were younger (59 ± 15 versus 62 ± 15 years: P = 0.014) and weighed less (70 ± 16 versus 80 ± 18 kg: P < 0.001). More were females (34% versus 27%: P = 0.004). Fewer had diabetes (25% versus 34%: P = 0.04) and peripheral vascular disease (PVD) (13% versus 23%: P = 0.008). Baseline KRU was similar in both groups (5.3 ± 2.4 for 2 × HD versus 5.1 ± 2.8 mL/min for 3 × HD: P = 0.507). In a mixed effects model correcting for between-group differences in comorbidities and demographics, 3×HD was associated with increased rate of loss of KRU and separation of KRU. In separate mixed effects models, group (2×HD versus 3×HD) was not associated with differences in serum potassium or phosphate, and the groups did not differ with respect to total standard Kt/V. Survival, adjusted for age, gender, weight, baseline KRU and comorbidity (prevalence of diabetes, cardiac disease, PVD and malignancy) was greater in the 2×HD group (hazard ratio 0.755: P = 0.044). In sub-analyses, the survival benefit was confined to women, and those of less than median bodyweight.

CONCLUSION

2×HD initiation as part of an incremental programme with regular monthly monitoring of KRU was safe and associated with a reduced rate of loss of RKF early after dialysis initiation and improved survival. Randomized controlled trials of this approach are indicated.

Protein-Bound Uremic Toxins in Hemodialysis Patients Relate to Residual Kidney Function, Are Not Influenced by Convective Transport, and Do Not Relate to Outcome

Protein-bound uremic toxins (PBUTs) are predominantly excreted by renal tubular secretion and hardly removed by traditional hemodialysis (HD). Accumulation of PBUTs is proposed to contribute to the increased morbidity and mortality of patients with end-stage kidney disease (ESKD). Preserved PBUT excretion in patients with residual kidney function (RKF) and/or increased PBUT clearance with improved dialysis techniques might improve the prognosis of patients with ESKD. The aims of this study are to explore determinants of PBUTs in HD patients, and investigate whether hemodiafiltration (HDF) lowers PBUT plasma concentrations, and whether PBUTs are related to the outcome. Predialysis total plasma concentrations of kynurenine, kynurenic acid, indoxyl sulfate, indole-3-acetic acid, p-cresyl sulfate, p-cresyl glucuronide, and hippuric acid were measured by UHPLC-MS at baseline and after 6 months of follow-up in the first 80 patients participating in the CONvective TRAnsport Study (CONTRAST), a randomized controlled trial that compared the effects of online HDF versus low-flux HD on all-cause mortality and new cardiovascular events. RKF was inversely related to kynurenic acid (p < 0.001), indoxyl sulfate (p = 0.001), indole-3-acetic acid (p = 0.024), p-cresyl glucuronide (p = 0.004) and hippuric acid (p < 0.001) plasma concentrations. Only indoxyl sulfate decreased by 8.0% (−15.3 to 34.6) in patients treated with HDF and increased by 11.9% (−15.4 to 31.9) in HD patients after 6 months of follow-up (HDF vs. HD: p = 0.045). No independent associations were found between PBUT plasma concentrations and either risk of all-cause mortality or new cardiovascular events. In summary, in the current population, RKF is an important determinant of PBUT plasma concentrations in HD patients. The addition of convective transport did not consistently decrease PBUT plasma concentrations and no relation was found between PBUTs and cardiovascular endpoints.

Association of Tubular Solute Clearance with Symptom Burden in Incident Peritoneal Dialysis

BACKGROUND AND OBJECTIVES

Residual kidney function is important to the health and wellbeing of patients with ESKD. We tested whether the kidney clearances of proximal tubular secretory solutes are associated with burden of uremic and heart failure symptoms among patients on peritoneal dialysis with residual kidney function.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We enrolled 29 patients on incident peritoneal dialysis with residual urine output >250 ml daily. We used targeted liquid chromatography-mass spectrometry to quantify plasma, 24-hour urine, and peritoneal dialysate concentrations of ten tubular secretory solutes. We calculated the kidney and peritoneal dialysis clearances of each secretory solute, creatinine, and urea, and we estimated a composite kidney and peritoneal secretion score. We assessed for uremic symptoms using the Dialysis Symptom Index and heart failure-related symptoms using the Kansas City Cardiomyopathy Questionnaire. We used linear regression to determine associations of composite secretory solute clearances and GFR_urea+Cr with Dialysis Symptom Index symptom score and Kansas City Cardiomyopathy Questionnaire summary score.

RESULTS

Mean residual kidney clearances of creatinine and urea were 8±5 and 9±6 ml/min per 1.73 m², respectively, and mean GFR_urea+Cr was 8±5 ml/min per 1.73 m². The residual kidney clearances of most secretory solutes were considerably higher than creatinine and urea clearance, and also, they were higher than their respective peritoneal dialysis clearances. After adjustments for age and sex, each SD higher composite kidney secretion score was associated with an 11-point lower Dialysis Symptom Index score (95% confidence interval, -20 to -1; P=0.03) and a 12-point higher Kansas City Cardiomyopathy Questionnaire score (95% confidence interval, 0.5- to 23-point higher score; P=0.04). Composite peritoneal dialysis secretion score was not associated with either symptom assessment.

CONCLUSIONS

Residual kidney clearances of secretory solutes are higher than peritoneal dialysis clearances. Kidney clearances of secretory solutes are associated with patient-reported uremic and heart failure-related symptoms.