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

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.

Non-invasive Quantification of Fat Deposits in Skeletal Muscle Predicts Cardiovascular Outcome in Kidney Failure

Fat accumulation in skeletal muscle was recently established as a major risk factor for cardiovascular disease (CVD) in the general population, but its relevance for patients with kidney failure is unknown. Here we examined the potential association between muscle radiation attenuation (MRA), a non-invasive indicator of fat deposits in muscle, and cardiovascular events in patients with kidney failure treated with peritoneal dialysis (PD) and investigated dynamic changes and determinants of MRA in this population. We retrospectively assessed MRA on computed tomography images collected yearly in 101 incident patients with kidney failure starting PD between January 2006 and December 2015. After a median of 21 months on dialysis, 34 patients had 58 non-fatal cardiovascular events, and 22 patients had died. Baseline MRA was associated with cardiovascular events during time on dialysis, and patients with higher MRA (reflecting lower amounts of fat in muscle) showed a reduced incidence of CVD, independently of traditional risk factors (adjusted HR, 0.91; 95% CI, 0.86-0.97, P = 0.006). Multivariate regression analysis identified old age, female gender, visceral fat area, and low residual urine volume as independent determinants of MRA. As compared with reference values from a healthy population, patients with kidney failure had lower MRA (i.e., increased fat accumulation), independently of age, gender, and body-mass index. The subset of patients who underwent kidney transplantation showed a significant increase in MRA after restoration of kidney function. These observations expand the association between ectopic fat accumulation and CVD to the population on dialysis, and suggest that kidney failure is reversibly associated with fatty muscle infiltration.

Initiating renal replacement therapy through incremental haemodialysis: Protocol for a randomized multicentre clinical trial

Background

Thrice-weekly haemodialysis is the usual dose when starting renal replacement therapy; however, this schedule is no longer appropriate since it does not consider residual renal function. Several reports have suggested the potential benefit of beginning haemodialysis less frequently and incrementally increasing the dose as the residual renal function decreases. However, all the data published so far are from observational studies. Thus, this clinical trial avoids any potential selection bias and will assess the possible benefits that have been observed in observational studies.

Methods/design

This report describes the study protocol of a randomized prospective multi-centre open-label clinical trial to evaluate whether starting renal replacement therapy with twice-weekly haemodialysis sessions preserves residual renal function better than the standard thrice-weekly regimen. We also explore other clinical parameters, such as concentrations of uremic toxins, dialysis doses, control of anaemia, removal of medium-weight uremic toxins, nutritional status, quality of life, hospital admissions and mortality. Only incident haemodialysis patients who can maintain a urea clearance rate KrU ≥ 2.5 mL/min/1.73 m² are eligible. Patient recruitment began on 1 January 2017 and will last for 2 years or until the required sample size has been recruited to ensure the established statistical power has been reached. The minimum follow-up period will be 1 year. Anuric patients with acute renal failure and patients who return to haemodialysis after a kidney transplant failure are excluded. It has been calculated that 44 patients should be recruited into each group to achieve a power of 80% in a two-sided comparison of means with a usual significance level of 0.05. A time-to-event analysis will estimate the probability of kidney function survival in both groups using the Kaplan–Meier method. Survival curves will be compared with log-rank tests. This survival analysis will be complemented with a proportional hazard model to estimate the hazard ratio of kidney function survival adjusted for any confounding factors. Analyses will be carried out in accordance with the intention-to-treat principle.

Discussion

The incremental initiation of dialysis may preserve residual renal function better than the conventional treatment, with similar or higher survival rates, as reported by observational studies. To our knowledge, this is the first clinical trial to evaluate whether initiating renal replacement therapy with twice-weekly haemodialysis sessions preserves residual renal function better than beginning with the standard thrice-weekly regimen.

Trial registration

ClinicalTrials.gov, NCT03302546. Registered on 5 October 2017.

Relationship between residual kidney function and symptom burden in haemodialysis patients

BACKGROUND

Residual kidney function (RKF) has been associated with improved solute clearance and survival in haemodialysis (HD) patients. However, whether RKF impacts symptom burden in HD patients is unknown.

AIMS

To determine the prevalence of RKF in HD patients and to explore associations between higher levels of RKF with symptom burden, as well as clinical and biochemical parameters.

METHODS

This is a single-centre, retrospective, observational study. RKF was assessed as urea clearance (KRU) by interdialytic urine collection. Symptom burden was measured using the palliative care outcome scale renal questionnaire.

RESULTS

A total of 90 maintenance HD patients was recruited; 31.9% had KRU ≥1 mL/min/1.73 m² . Patients with KRU ≥1 mL/min/1.73 m² reported fewer symptoms (5.3 ± 3.5 vs 7.7 ± 3.8) (P = 0.011), including less shortness of breath (15% vs 55%) (P = 0.0013) and vomiting (0% vs 30%) (P = 0.0016). Higher RKF was associated with lower β₂ -microglobilin (P < 0.0001), and lower serum potassium (P = 0.02), but no difference in phosphate, haemoglobin, C-reactive protein or serum albumin.

CONCLUSION

Higher RKF was significantly associated with fewer symptoms, and lower serum β₂ -microglobulin and potassium, suggesting that strategies to preserve RKF may be beneficial.

Association of Mineral Bone Disorder With Decline in Residual Kidney Function in Incident Hemodialysis Patients

Abnormalities of mineral bone disorder (MBD) parameters have been suggested to be associated with poor renal outcome in predialysis patients. However, the impact of those parameters on decline in residual kidney function (RKF) is uncertain among incident hemodialysis (HD) patients. We performed a retrospective cohort study in 13,772 patients who initiated conventional HD during 2007 to 2011 and survived 6 months of dialysis. We examined the association of baseline serum phosphorus, calcium, intact parathyroid hormone (PTH), and alkaline phosphatase (ALP) with a decline in RKF. Decline in RKF was assessed by estimated slope of renal urea clearance (KRU) over 6 months from HD initiation. Our cohort had a mean ± SD age of 62 ± 15 years; 64% were men, 57% were white, 65% had diabetes, and 51% had hypertension. The median (interquartile range [IQR]) baseline KRU level was 3.4 (2.0, 5.2) mL/min/1.73 m² . The median (IQR) estimated 6-month KRU slope was -1.47 (-2.24, -0.63) mL/min/1.73 m² per 6 months. In linear regression models, higher phosphorus categories were associated with a steeper 6-month KRU slope compared with the reference category (phosphorus 4.0 to <4.5 mg/dL). Lower calcium and higher intact PTH and ALP categories were also associated with a steeper 6-month KRU slope compared with their respective reference groups (calcium 9.2 to <9.5 mg/dL; intact PTH 150 to <250 pg/mL; ALP <60 U/L). The increased number of parameter abnormalities had an additive effect on decline in RKF. Abnormalities of MBD parameters including higher phosphorus, intact PTH, ALP and lower calcium levels were independently associated with decline in RKF in incident HD patients. © 2019 American Society for Bone and Mineral Research. © 2019 American Society for Bone and Mineral Research.

Modified creatinine index and risk for long-term infection-related mortality in hemodialysis patients: ten-year outcomes of the Q-Cohort Study

Modified creatinine (Cr) index, calculated by age, sex, pre-dialysis serum Cr concentration, and Kt/V for urea, is an indicator of skeletal muscle mass in hemodialysis (HD) patients. It remains unknown whether the modified Cr index predicts infection-related mortality in this population. We investigated the association between the modified Cr index and infection-related mortality. A total of 3046 patients registered in the Q-Cohort Study, a multicenter, observational study of HD patients, were analyzed. Associations between sex-specific quartiles (Q1–Q4) of the modified Cr index and the risk for infection-related mortality were analyzed by Cox proportional hazard model. During a median follow-up of 8.8 years, 387 patients died of infection. The estimated risk for infection-related mortality was significantly higher in the lower quartiles (Q1, Q2, and Q3) than in the highest quartile (Q4) as the reference group (hazard ratios and 95% confidence intervals [CI]: Q1, 2.89 [1.70–5.06], Q2, 2.76 [1.72–4.62], and Q3, 1.79 [1.12–2.99]). The hazard ratio (95% CI) for a 1 mg/kg/day decrease in the modified Cr index was 1.18 (1.09–1.27, P < 0.01) for infection-related mortality. In conclusion, a lower modified Cr index is associated with an increased risk for long-term infection-related mortality in the HD population.

Cardiovascular risk factors in children on dialysis: an update

Cardiovascular disease (CVD) is a life-limiting comorbidity in patients with chronic kidney disease (CKD). In childhood, imaging studies have demonstrated early phenotypic characteristics including increases in left ventricular mass, carotid artery intima-media thickness, and pulse wave velocity, which occur even in young children with early stages of CKD. Vascular calcifications are the signature of an advanced phenotype and are mainly found in adolescents and young adults treated with dialysis. Association studies have provided valuable information regarding the significance of a multitude of risk factors in promoting CVD in children with CKD by using intermediate endpoints of measurements of surrogate parameters of CVD. Dialysis aggravates pre-existing risk factors and accelerates the progression of CVD with additional dialysis-related risk factors. Coronary artery calcifications in children and young adults with CKD accumulate in a time-dependent manner on dialysis. Identification of risk factors has led to improved understanding of principal mechanisms of CKD-induced damage to the cardiovascular system. Treatment strategies include assessment and monitoring of individual risk factor load, optimization of treatment of modifiable risk factors, and intensified hemodialysis if early transplantation is not possible.

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.

Narrative Review of Incremental Hemodialysis

The prescription of hemodialysis (HD) in patients with incident end-stage kidney disease (ESKD) is fundamentally empirical. The abrupt transition from nondialysis chronic kidney disease (CKD) to thrice-weekly in-center HD of much the same dialysis intensity as in those with prevalent ESKD underappreciates the progressive nature of kidney disease whereby the decline in renal function has been gradual and ongoing-including at the time of HD initiation. Adjuvant pharmacologic treatment (i.e., diuretics, acid buffers, potassium binders), coupled with residual kidney function (RKF), can complement an initial HD regimen of lower intensity. Barriers to less intensive HD in incident ESKD include risk of inadequate clearance of uremic toxins due to variable and unexpected loss of RKF, lack of patient adherence to assessments of RKF or adjustment of HD intensity, increased burden for all stakeholders in the dialysis units, and negative financial repercussions. A stepped dialysis regimen with scheduled transition from time-delineated twice-weekly HD to thrice-weekly HD could represent an effective and safe strategy to standardize incremental HD in patients with CKD transitioning to early-stage ESKD. Patients' adherence and survival as well as other clinical outcomes should be rigorously evaluated in clinical trials before large-scale implementation of different incremental schedules of HD. This review discusses potential benefits of and barriers to alternative dialysis regimens in patients with incident ESKD, with emphasis on twice-weekly HD with pharmacologic therapy, and summarizes in-progress clinical trials of incremental HD schedules.

Predicting Residual Function in Hemodialysis and Hemodiafiltration-A Population Kinetic, Decision Analytic Approach

In this study, we introduce a novel framework for the estimation of residual renal function (RRF), based on the population compartmental kinetic behavior of beta 2 microglobulin (B2M) and its dialytic removal. Using this model, we simulated a large cohort of patients with various levels of RRF receiving either conventional high-flux hemodialysis or on-line hemodiafiltration. These simulations were used to estimate a novel population kinetic (PK) equation for RRF (PK-RRF) that was validated in an external public dataset of real patients. We assessed the performance of the resulting equation(s) against their ability to estimate urea clearance using cross-validation. Our equations were derived entirely from computer simulations and advanced statistical modeling and had extremely high discrimination (Area Under the Curve, AUC 0.888–0.909) when applied to a human dataset of measurements of RRF. A clearance-based equation that utilized predialysis and postdialysis B2M measurements, patient weight, treatment duration and ultrafiltration had higher discrimination than an equation previously derived in humans. Furthermore, the derived equations appeared to have higher clinical usefulness as assessed by Decision Curve Analysis, potentially supporting decisions for individualizing dialysis prescriptions in patients with preserved RRF.

Higher serum phosphorus predicts residual renal function loss in male but not female incident peritoneal dialysis patients

BACKGROUND

Elevated serum phosphorus level is a risk factor for progression of chronic kidney disease in non-dialysis patients. However, the association of serum phosphorus level with residual renal function (RRF) loss among incident continuous ambulatory peritoneal dialysis (CAPD) patients remains unclear.

METHODS

We performed a retrospective analysis of prospectively collected cohort of 1245 incident CAPD patients from January 2006 to December 2015 and followed up until December 2017. Patients were stratified into tertiles according to baseline serum phosphorus levels. RRF loss was defined as residual glomerular filtration rate (mL/min/1.73 m²) reaching zero or estimated urine output less than 200 mL/day on two successive clinic visits. Propensity-score matched Cox's proportional hazards and competing risk models were performed to examine the association of serum phosphorus with RRF loss.

RESULTS

A total of 421 (33.82%) patients had loss of RRF over a median follow-up of 26.23 months. In the entire cohort, elevated serum phosphorus was associated with increased risk for RRF loss after adjustment. In the propensity-score matched cohort, patients in the 3rd tertile of serum phosphorus had a 51% higher risk of RRF loss than those in the combination of the 1st and 2nd tertiles. Furthermore, the association of serum phosphorus level with RRF loss differed by sex (interaction P = 0.018). The adjusted HRs per 1 mg/dL increase in serum phosphorus level of RRF loss were 1.32 (95% CI 1.15-1.50, P < 0.001) for male and 1.03 (95% CI 0.87-1.21, P = 0.750) for female, respectively. These findings persisted in competing risk analysis.

CONCLUSION

Higher serum phosphorus levels independently predicts RRF loss in men treated with CAPD.

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

Rationale & Objective

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

Study Design

Retrospective, predictive modeling and model validation.

Setting & Participants

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

Predictors

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

Outcomes

Residual kidney urea clearance.

Analytic Approach

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

Results

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

Limitations

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

Conclusions

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

Pro: The rationale for dietary therapy for patients with advanced chronic kidney disease

Dietary treatment offers many benefits to patients with advanced chronic kidney disease (CKD) who are approaching the need for renal replacement therapy. A large number of these benefits are independent of whether diets slow the rate of progression of CKD. These diets are low in protein and many minerals, and provide adequate energy for the CKD patient. The diets can reduce accumulation of potentially toxic metabolic products derived from protein and amino acid degradation, maintain a healthier balance of body water, sodium, potassium, phosphorus, calcium and other minerals, and prevent or improve protein-energy wasting. Such diets may enable patients to safely delay the onset of chronic dialysis therapy or kidney transplantation. Dietary therapy may also augment the effectiveness of infrequent or incremental dialysis by maintaining healthier metabolic and clinical status and may enable some end-stage renal disease patients to avoid the need for temporary placement of hemodialysis catheters while their arterial venous fistulae or grafts mature. The anxiety that many advanced CKD patients commonly experience with regard to starting dialysis may incentivize them to accept and adhere to dietary therapy.

Renal Perfusion during Hemodialysis: Intradialytic Blood Flow Decline and Effects of Dialysate Cooling

BACKGROUND

Residual renal function (RRF) confers survival in patients with ESRD but declines after initiating hemodialysis. Previous research shows that dialysate cooling reduces hemodialysis-induced circulatory stress and protects the brain and heart from ischemic injury. Whether hemodialysis-induced circulatory stress affects renal perfusion, and if it can be ameliorated with dialysate cooling to potentially reduce RRF loss, is unknown.

METHODS

We used renal computed tomography perfusion imaging to scan 29 patients undergoing continuous dialysis under standard (36.5°C dialysate temperature) conditions; we also scanned another 15 patients under both standard and cooled (35.0°C) conditions. Imaging was performed immediately before, 3 hours into, and 15 minutes after hemodialysis sessions. We used perfusion maps to quantify renal perfusion. To provide a reference to another organ vulnerable to hemodialysis-induced ischemic injury, we also used echocardiography to assess intradialytic myocardial stunning.

RESULTS

During standard hemodialysis, renal perfusion decreased 18.4% (P<0.005) and correlated with myocardial injury (r=-0.33; P<0.05). During sessions with dialysis cooling, patients experienced a 10.6% decrease in perfusion (not significantly different from the decline with standard hemodialysis), and ten of the 15 patients showed improved or no effect on myocardial stunning.

CONCLUSIONS

This study shows an acute decrease in renal perfusion during hemodialysis, a first step toward pathophysiologic characterization of hemodialysis-mediated RRF decline. Dialysate cooling ameliorated this decline but this effect did not reach statistical significance. Further study is needed to explore the potential of dialysate cooling as a therapeutic approach to slow RRF decline.

The effect of gender on survival for hemodialysis patients: Why don't women live longer than men?

Women in the general population have a survival advantage over men, but this advantage is not sustained in end-stage kidney disease (ESKD) patients treated by hemodialysis. To understand why gender may affect survival we need to understand confounders which may affect dialysis practices. The current paradigm is to prescribe hemodialysis to achieve a target dialyzer urea clearance adjusted to total body water volume (Kt/V_urea ). Estimated glomerular filtration calculated from serum creatinine is often used to determine when patients start dialysis; as creatinine generation rates are lower in women, this may potentially result in a lead time bias with male patients starting dialysis earlier than females. When hemodialysis dose is scaled to total body water (Kt/V_urea ) women receive shorter dialysis session times. Scaling dialysis for body surface area may be more appropriate since urea generation (a surrogate for uremic toxin production) depends upon resting energy expenditure (ie, cellular metabolism) which reflects internal organ sizes. Resting energy expenditure is proportionally greater for smaller people. Women are generally smaller than men and as such have smaller sized internal organs. However, when comparing individuals, then internal organ size is best adjusted for using body surface area, not body water. The shorter, resultant dialysis session also results in lower middle molecule clearances, increases fluid removal rates and the risk of intra-dialytic hypotension; the latter potentially results in earlier loss of residual renal function. Observational studies report that the association between survival and dialyzer Kt/V_urea is improved after adjustment for body surface area, or energy expenditure. These studies also demonstrated that the conventional prescription of hemodialysis based on current Kt/V_urea targets leads to less treatment delivered to women. These multiple consequences of the generally smaller size of women compared with men may account for the unexpectedly higher relative mortality for women. As such, prospective studies investigating alternative scaling parameters are required to confirm that increasing dialysis treatments for women improves survival.

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.

Uremic Toxin Concentrations are Related to Residual Kidney Function in the Pediatric Hemodialysis Population

Protein-bound uremic toxins (PBUTs) play a role in the multisystem disease that children on hemodialysis (HD) are facing, but little is known about their levels and protein binding (%PB). In this study, we evaluated the levels and %PB of six PBUTs cross-sectionally in a large pediatric HD cohort (n = 170) by comparing these with healthy and non-dialysis chronic kidney disease (CKD) stage 4-5 (n = 24) children. In parallel β2-microglobulin (β2M) and uric acid (UA) were evaluated. We then explored the impact of age and residual kidney function on uremic toxin levels and %PB using analysis of covariance and Spearman correlation coefficients (r_s). We found higher levels of β2M, p-cresyl glucuronide (pCG), hippuric acid (HA), indole acetic acid (IAA), and indoxyl sulfate (IxS) in the HD compared to the CKD4-5 group. In the HD group, a positive correlation between age and pCG, HA, IxS, and pCS levels was shown. Residual urine volume was negatively correlated with levels of β2M, pCG, HA, IAA, IxS, and CMPF (r_s -0.2 to -0.5). In addition, we found overall lower %PB of PBUTs in HD versus the CKD4-5 group, and showed an age-dependent increase in %PB of IAA, IxS, and pCS. Furhtermore, residual kidney function was overall positively correlated with %PB of PBUTs. In conclusion, residual kidney function and age contribute to PBUT levels and %PB in the pediatric HD population.

Incremental hemodialysis, a valuable option for the frail elderly patient

Management of older people on dialysis requires focus on the wider aspects of aging as well as dialysis. Recognition and assessment of frailty is vital in changing our approach in elderly patients. Current guidelines in dialysis have a limited evidence base across all age group, but particularly the elderly. We need to focus on new priorities of care when we design guidelines "for people not diseases". Patient-centered goal-directed therapy, arising from shared decision-making between physician and patient, should allow adaption of the dialysis regime. Hemodialysis (HD) in the older age group can be complicated by intradialytic hypotension, prolonged time to recovery, and access-related problems. There is increasing evidence relating to the harm associated with the delivery of standard thrice-weekly HD. Incremental HD has a lower burden of treatment. There appears to be no adverse clinical effects during the first years of dialysis in presence of a significant residual kidney function. The advantages of incremental HD might be particularly important for elderly patients with short life expectancy. There is a need for more research into specific topics such as the assessment of the course of frailty with progression of chronic kidney disease and after dialysis initiation, the choice of dialysis modality impacting on the trajectory of frailty, the timing of dialysis initiation impacting on frailty or on other outcomes. In conclusion, understanding each individual's goals of care in the context of his or her life experience is particularly important in the elderly, when overall life expectancy is relatively short, and life experience or quality of life may be the priority.

Precision Medicine in the Transition to Dialysis and Personalized Renal Replacement Therapy

Launched in 2016, the overarching goal of the Precision Medicine Initiative is to promote a personalized approach to disease management that takes into account an individual's unique underlying biology and genetics, lifestyle, and environment, in lieu of a one-size-fits-all model. The concept of precision medicine is pervasive across many areas of nephrology and has been particularly relevant to the care of advanced chronic kidney disease patients transitioning to end-stage kidney disease (ESKD). Given many uncertainties surrounding the optimal transition of incident ESKD patients to dialysis and transplantation, as well as the high mortality rates observed during this delicate transition period, there is a pressing urgency for implementing precision medicine in the management of this population. Although the traditional paradigm has been to commence incident hemodialysis patients on a 3 times/week treatment regimen, largely driven by adequacy targets, there has been growing recognition that alternative treatment regimens (ie, incremental hemodialysis) may be preferred among certain subpopulations when taking into consideration factors such as patients' residual kidney function, volume status fluctuations, symptoms, and preferences. In this review, we examine the origins of current practices in how dialysis is initiated among incident ESKD patients; incremental dialysis therapy as a dynamic and patient-centric approach that is tailored to patients' unique characteristics; recent data on the incremental hemodialysis regimen and outcomes; and future research directions using a precision nephrology approach to ESKD management with the potential to develop novel approaches, tools, and collaborative efforts to improve the health, well-being, and survival of this population.

How can we advance in renal replacement therapy techniques?

End-Stage Renal Disease (ESRD) is one of the major causes of morbidity and mortality worldwide. Although the incidence of ESRD is relatively stable, the prevalence of maintenance dialysis is increasing, and it is expected to reach a staggering 5439 million patients worldwide by 2030. Despite the great technological evolution that has taken place in recent years, most patients are still treated with in-centre haemodialysis and their prognosis remains far from desirable. Since 1980, there has been an increasing interest in the development of a portable device for renal replacement therapy (RRT), which ultimately led to the creation of the Wearable Artificial Kidney (WAK) and the Wearable Ultrafiltration (WUF) system. Portable RRT devices may be acceptable alternatives that deal with several unmet clinical needs of ESRD patients. So far, 3 important human studies with WAK and WUF have been carried out and, although these devices require considerable technological improvement, their safety and efficacy in solute clearance and fluid removal is undeniable. In this article, we review the evolution of the WAK and the WUF and the main clinical trials performed, highlighting some of their technical features. Some of the main possible clinical advantages that could be achieved with these devices, as well as some economic aspects, are also pointed out. In the future, all renal replacement therapy techniques should evolve to perfectly match the clinical and personal needs of each patient, allowing for an improved health-related quality of life.

Hyponatremia in the Dialysis Population

Sodium derangements are among the most frequently encountered electrolyte disorders in patients with end-stage renal disease. As dialysis patients are predisposed to hyponatremia via multiple pathways, assessment of extracellular volume status is an essential first step in disentangling potential etiologic factors. In addition, multiple large population-based studies indicate that proxies of malnutrition (e.g., low body mass index, serum albumin, and serum creatinine levels) and loss of residual kidney function are important determinants of hyponatremia in dialysis patients. Among hemodialysis and peritoneal dialysis patients, evidence suggests that incrementally lower sodium levels are associated with increasingly higher death risk, highlighting the long-term risk of hyponatremia. Whereas in conventional survival models incrementally lower serum sodium concentrations are associated with worse mortality in hemodialysis patients, studies that have examined repeated measures of predialysis sodium have demonstrated mixed associations of time-varying sodium with higher mortality risk (i.e., U-shaped vs. inverse linear relationships). Although the causality of the hyponatremia-mortality association in dialysis patients remains uncertain, there are several plausible pathways by which lower sodium levels may lead to higher death risk, including central nervous system toxicity, falls and fractures, infection-related complications, and impaired cardiac function. Areas of uncertainty ripe for future studies include the following: (i) mechanistic pathways by which lower serum sodium levels are linked with higher mortality in dialysis patients, (ii) whether correction of sodium derangements improves outcomes, (iii) the optimal sodium target, and (iv) the impact of age and other sociodemographic factors on hyponatremia-outcome associations.

IHDIP: a controlled randomized trial to assess the security and effectiveness of the incremental hemodialysis in incident patients

BACKGROUND

Most people who make the transition to renal replacement therapy (RRT) are treated with a fixed dose thrice-weekly hemodialysis réegimen, without considering their residual kidney function (RKF). Recent papers inform us that incremental hemodialysis is associated with preservation of RKF, whenever compared with conventional hemodialysis. The objective of the present controlled randomized trial (RCT) is to determine if start HD with one sessions per week (1-Wk/HD), it is associated with better patient survival and other safety parameters.

METHODS/DESIGN

IHDIP is a multicenter RCT experimental open trial. It is randomized in a 1:1 ratio and controlled through usual clinical practice, with a low intervention level and non-commercial. It includes 152 incident patients older than 18 years, with a RRF of ≥4 ml/min/1.73 m2, measured by renal clearance of urea (KrU). The intervention group includes 76 patients who will start with incremental HD (1-Wk/HD). The control group includes 76 patients who will start with thrice-weekly hemodialysis régimen. The primary outcome is assessing the survival rate, while the secondary outcomes are the morbidity rate, the clinical parameters, the quality of life and the efficiency.

DISCUSSION

This study will enable to know the number of sessions a patient should receive when starting HD, depending on his RRF. The potentially important clinical and financial implications of incremental hemodialysis warrant this RCT.

TRIAL REGISTRATION

U.S. National Institutes of Health, ClinicalTrials.gov . Number: NCT03239808 , completed 13/04/2017.

SPONSOR

Foundation for Training and Research of Health Professionals of Extremadura.

Health-related quality of life in peritoneal dialysis patients: A narrative review

Health-related quality of life (HRQOL) is an important aspect of patients´ health that should be an integral part of the evaluation of patient-centered outcomes, not least because HRQOL associates with patients´ morbidity and mortality. This applies also to chronic kidney disease patients, including those dependent on renal replacement therapies, the type of which may influence patients´ perception of HRQOL. Several studies have addressed HRQOL in chronic kidney disease patients undergoing renal replacement therapies, especially transplanted patients and hemodialysis patients, while publications concerning peritoneal dialysis (PD) patients are scarcer. This review describes some of the methods used to assess HRQOL, factors influencing HRQOL in PD patients, HRQOL in PD vs hemodialysis, and the relation between HRQOL and patient outcomes. We conclude that assessment of HRQOL-often neglected at present-should be included as a standard measure of patient-centered outcomes and when monitoring the quality and effectiveness of renal care including PD treatment.

Association of Continuation of Loop Diuretics at Hemodialysis Initiation with Clinical Outcomes

BACKGROUND AND OBJECTIVES

Loop diuretics are commonly used to manage nondialysis-dependent CKD. Despite benefits of augmented urine output, loop diuretics are often discontinued after dialysis initiation. Here, we assessed the association of the early decision to continue loop diuretics at hemodialysis start with clinical outcomes during the first year of dialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We considered all patients on in-center hemodialysis at a large dialysis organization (2006-2013) with Medicare Part A and D benefits who had an active supply of a loop diuretic at dialysis initiation (n=11,297). Active therapy was determined on the basis of whether loop diuretic prescription was refilled after dialysis initiation and within 30 days of exhaustion of prior supply. Patients were followed under an intention-to-treat paradigm for up to 12 months for rates of death, hospitalization, and intradialytic hypotension and mean monthly values of interdialytic weight gain, serum potassium, predialysis systolic BP, and ultrafiltration rates.

RESULTS

We identified 5219 patients who refilled a loop diuretic and 6078 eligible controls who did not. After adjustments for patient mix and clinical differences, continuation of loop diuretics was associated with lower hospitalization (adjusted incidence rate ratio, 0.93; 95% confidence interval, 0.89 to 0.98) and intradialytic hypotension (adjusted incidence rate ratio, 0.95; 95% confidence interval, 0.92 to 0.99) rates, no difference in death rate (adjusted hazard ratio, 0.92; 95% confidence interval, 0.84 to 1.01), and lower interdialytic weight gain (P=0.03).

CONCLUSIONS

Continuation of loop diuretics after hemodialysis initiation was associated with lower rates of hospitalization and intradialytic hypotension as well as lower interdialytic weight gain, but there was no difference in mortality over the first year of dialysis.

Individualized Hemodialysis Treatment: A Perspective on Residual Kidney Function and Precision Medicine in Nephrology

Background: Residual kidney function (RKF) is often expected to inevitably and rapidly decline among hemodialysis patients and, hence, has been inadvertently ignored in clinical practice. The importance of RKF has been revisited in some recent studies. Given that patients with end-stage renal disease now tend to initiate maintenance hemodialysis therapy with higher RKF levels, there seem to be important opportunities for incremental hemo­dialysis by individualizing the dose and frequency according to their RKF levels. This approach is realigned with precision medicine and patient-centeredness. Summary: In this article, we first review the available methods to estimate RKF among hemodialysis patients. We then discuss the importance of maintaining and monitoring RKF levels based on a variety of clinical aspects, including volume overload, blood pressure control, mineral and bone metabolism, nutrition, and patient survival. We also review several potential measures to protect RKF: the use of high-flux and biocompatible membranes, the use of ultrapure dialysate, the incorporation of hemodiafiltration, incremental hemodialysis, and a low-protein diet, as well as general care such as avoiding nephrotoxic events, maintaining appropriate blood pressure, and better control of mineral and bone disorder parameters. Key Message: Individualized hemodialysis regimens may maintain RKF, lead to a better quality of life without compromising long-term survival, and ensure precision medicine and patient-centeredness in nephrology practice.

Rationale and design of DiPPI: A randomized controlled trial to evaluate the safety and effectiveness of progressive hemodialysis in incident patients

INTRODUCTION

Progressive haemodialysis (HD) is a starting regime for renal replacement therapy (RRT) adapted to each patient's necessities. It is mainly conditioned by the residual renal function (RRF). The frequency of sessions with which patients start HD (one or two sessions per week), is lower than that for conventional HD (three times per week). Such frequency is increased (from one to two sessions, and from two to three sessions) as the RRF declines.

METHODOLOGY/DESIGN

IHDIP is a multicentre randomised experimental open trial. It is randomised in a 1:1 ratio and controlled through usual clinical practice, with a low intervention level and non-commercial. It includes 152 patients older than 18 years with chronic renal disease stage 5 and start HD as RRT, with an RRF of ≥4ml/min/1.73m², measured by renal clearance of urea (KrU). The intervention group includes 76 patients who will start with one session of HD per week (progressive HD). The control group includes 76 patients who will start with three sessions per week (conventional HD). The primary purpose is assessing the survival rate, while the secondary purposes are the morbidity rate (hospital admissions), the clinical parameters, the quality of life and the efficiency.

DISCUSSION

This study will enable us to know, with the highest level of scientific evidence, the number of sessions a patient should receive when starting the HD treatment, depending on his/her RRF.

TRIAL REGISTRATION

Registered at the U.S. National Institutes of Health, ClinicalTrials.gov under the number NCT03239808.

Peritoneal dialysis has optimal intradialytic hemodynamics and preserves residual renal function: Why isn't it better than hemodialysis?

Rates of cardiovascular mortality are disproportionately high in patients with end stage kidney disease receiving dialysis. However, it is now generally accepted that patient survival is broadly equivalent between the two most frequently used forms of dialysis, in-center hemodialysis (HD) and peritoneal dialysis (PD). This equivalent patient survival is notable when considering how specific aspects of HD have been shown to contribute to morbidity and mortality. These include more rapid loss of residual renal function (RRF), HD-induced myocardial and cerebral ischemia, and risk factors associated with the intermittent delivery of HD. Potential mechanisms specific to PD that may drive cardiovascular disease include the metabolic consequences of excessive absorption of glucose and glucose degradation products (GDPs), inadequate volume control, and high rates of hypokalemia. The aim of this review is to compare and contrast the different drivers of adverse outcomes between the dialysis modalities, as greater understanding of this may help in patient-centered decision-making when considering options for renal replacement therapy.

Prescribing Hemodialysis or Hemodiafiltration: When One Size Does Not Fit All the Proposal of a Personalized Approach Based on Comorbidity and Nutritional Status

There is no simple way to prescribe hemodialysis. Changes in the dialysis population, improvements in dialysis techniques, and different attitudes towards the initiation of dialysis have influenced treatment goals and, consequently, dialysis prescription. However, in clinical practice prescription of dialysis still often follows a "one size fits all" rule, and there is no agreed distinction between treatment goals for the younger, lower-risk population, and for older, high comorbidity patients. In the younger dialysis population, efficiency is our main goal, as assessed by the demonstrated close relationship between depuration (tested by kinetic adequacy) and survival. In the ageing dialysis population, tolerance is probably a better objective: "good dialysis" should allow the patient to attain a stable metabolic balance with minimal dialysis-related morbidity. We would like therefore to open the discussion on a personalized approach to dialysis prescription, focused on efficiency in younger patients and on tolerance in older ones, based on life expectancy, comorbidity, residual kidney function, and nutritional status, with particular attention placed on elderly, high-comorbidity populations, such as the ones presently treated in most European centers. Prescription of dialysis includes reaching decisions on the following elements: dialysis modality (hemodialysis (HD) or hemodiafiltration (HDF)); type of membrane (permeability, surface); and the frequency and duration of sessions. Blood and dialysate flow, anticoagulation, and reinfusion (in HDF) are also briefly discussed. The approach described in this concept paper was developed considering the following items: nutritional markers and integrated scores (albumin, pre-albumin, cholesterol; body size, Body Mass Index (BMI), Malnutrition Inflammation Score (MIS), and Subjective Global Assessment (SGA)); life expectancy (age, comorbidity (Charlson Index), and dialysis vintage); kinetic goals (Kt/V, normalized protein catabolic rate (n-PCR), calcium phosphate, parathyroid hormone (PTH), beta-2 microglobulin); technical aspects including vascular access (fistula versus catheter, degree of functionality); residual kidney function and weight gain; and dialysis tolerance (intradialytic hypotension, post-dialysis fatigue, and subjective evaluation of the effect of dialysis on quality of life). In the era of personalized medicine, we hope the approach described in this concept paper, which requires validation but has the merit of providing innovation, may be a first step towards raising attention on this issue and will be of help in guiding dialysis choices that exploit the extraordinary potential of the present dialysis "menu".

[Incremental haemodialysis]

The majority of incidental haemodialysis patients are systematically treated at the rate of three sessions per week, regardless of their level of residual kidney function. Incremental haemodialysis is a therapeutic strategy adapted to the residual kidney function level of each patient, to offer patients only the "dialysis dose" needed to supplement their residual kidney function, while ensuring that they achieve the objective of total clearance (renal+per-HD) recommended (weekly Standard Kt/V urea>2.3 volumes. Incremental haemodialysis therefore allows a lower dose and lower dialysis frequency in patients with residual kidney function. Incremental haemodialysis through better residual kidney function preservation could improve patient survival and also have other benefits in terms of quality of life, preservation of vascular access and in terms of decreased expenditure health. Some logistical hurdles make its safely prescription still difficult but software should soon be made available to practitioners for a simpler and more accurate daily management of this prescription.

Conventional dialysis in the elderly: How lenient should our guidelines be?

There has been a dramatic, worldwide expansion in life expectancy across the last century. This has resulted in a progressively more elderly and comorbid population. It is increasingly recognized that healthcare in this group needs to move to the concept of "adding life to years". Recognition and assessment of frailty is vital in changing our approach in elderly patients. Current guidelines in dialysis have a limited evidence base across all age groups, but particularly the elderly and serve them poorly. Moreover, the burden of guidelines for each comorbidity of the multimorbid patient is increasing and can be conflicting. Finally, there is increasing evidence relating to the harm associated with the delivery of conventional dialysis. In dialysis patients, frailty is the overwhelming determinant in relation to patient-specific outcomes rather than modality of treatment; therefore, the focus should be on promoting quality of life. We need to focus on new priorities of care when we design guidelines "for people not diseases". Patient-centered goal-directed therapy, arising from shared decision making between physician and patient, should allow adaption of the dialysis regime to maximize opportunities while minimizing treatment-related morbidity and concentrating on alleviating symptoms.

Predialysis Kidney Function and Its Rate of Decline Predict Mortality and Hospitalizations After Starting Dialysis

OBJECTIVE

To determine whether kidney function level and its rate of decline in the immediate predialysis period among veterans transitioning to end-stage renal disease (ESRD) predict postdialysis mortality and hospitalization.

PATIENTS AND METHODS

In 19,985 veterans transitioning to ESRD during the period October 1, 2007, to March 30, 2014, we examined kidney function and its slope over the final year of the pre-ESRD(prelude) period. Two categories of low vs high estimated glomerular filtration rate (eGFR, dichotomized at 10 mL/min/1.73 m²) and slow vs fast slope (dichotomized at -10 mL/min/1.73 m²/y) were combined into 4 groups. Their associations with 12-month post-ESRD all-cause and cardiovascular (CV) mortality and hospitalization rates were examined in adjusted models accounting for clinical characteristics and laboratory measurements at transition.

RESULTS

Patients, 66±11 years old, and 34% blacks, had a median (interquartile range) eGFR at transition and slope of 9.7 (7.1-13.3) mL/min/1.73 m² and -10.5 (-18.8 to -5.9) mL/min/1.73 m²/y, respectively. Patients with a low eGFR and slow slope had the lowest 12-month all-cause and CV mortality risks and hospitalization rate. Conversely, patients with high eGFR and fast slope had the highest risk of all-cause and CV mortality and hospitalization rate compared with patients with a low eGFR and slow slope. This relationship persisted in sensitivity analyses, including propensity scoring.

CONCLUSION

A kidney profile of a low eGFR and slow slope in the prelude period is associated with favorable early dialysis outcomes in veteran patients. Trials to examine a more conservative approach to dialysis are warranted.