Estimated GFR at Dialysis Initiation and Mortality in Children and Adolescents

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.

SETD2 deficiency promotes renal fibrosis through the TGF-β/Smad signalling pathway in the absence of VHL

BACKGROUND

Renal fibrosis is the final development pathway and the most common pathological manifestation of chronic kidney disease. Epigenetic alteration is a significant intrinsic factor contributing to the development of renal fibrosis. SET domain-containing 2 (SETD2) is the sole histone H3K36 trimethyltransferase, catalysing H3K36 trimethylation. There is evidence that SETD2-mediated epigenetic alterations are implicated in many diseases. However, it is unclear what role SETD2 plays in the development of renal fibrosis.

METHODS

Kidney tissues from mice as well as HK2 cells were used as research subjects. Clinical databases of patients with renal fibrosis were analysed to investigate whether SETD2 expression is reduced in the occurrence of renal fibrosis. SETD2 and Von Hippel-Lindau (VHL) double-knockout mice were used to further investigate the role of SETD2 in renal fibrosis. Renal tubular epithelial cells isolated from mice were used for RNA sequencing and chromatin immunoprecipitation sequencing to search for molecular signalling pathways and key molecules leading to renal fibrosis in mice. Molecular and cell biology experiments were conducted to analyse and validate the role of SETD2 in the development of renal fibrosis. Finally, rescue experiments were performed to determine the molecular mechanism of SETD2 deficiency in the development of renal fibrosis.

RESULTS

SETD2 deficiency leads to severe renal fibrosis in VHL-deficient mice. Mechanically, SETD2 maintains the transcriptional level of Smad7, a negative feedback factor of the transforming growth factor-β (TGF-β)/Smad signalling pathway, thereby preventing the activation of the TGF-β/Smad signalling pathway. Deletion of SETD2 leads to reduced Smad7 expression, which results in activation of the TGF-β/Smad signalling pathway and ultimately renal fibrosis in the absence of VHL.

CONCLUSIONS

Our findings reveal the role of SETD2-mediated H3K36me3 of Smad7 in regulating the TGF-β/Smad signalling pathway in renal fibrogenesis and provide an innovative insight into SETD2 as a potential therapeutic target for the treatment of renal fibrosis.

Urgent Implantation of Peritoneal Dialysis Catheter in Chronic Kidney Disease and Acute Kidney Injury-A Review

Acute kidney injury (AKI) and sudden exacerbation of chronic kidney disease (CKD) frequently necessitate urgent kidney replacement therapy (UKRT). Peritoneal dialysis (PD) is recognized as a viable modality for managing such patients. Urgent-start peritoneal dialysis (USPD) may be associated with an increased number of complications and is rarely utilized. This review examines recent literature investigating the clinical outcomes of USPD in CKD and AKI. Relevant research was identified through searches of the MEDLINE (PubMed), Scopus, Web of Science, and Google Scholar databases using MeSH terms and relevant keywords. Included studies focused on the emergency use of peritoneal dialysis in CKD or AKI and reported treatment outcomes. While no official recommendations exist for catheter implantation in USPD, the impact of the technique itself on outcomes was found to be less significant compared with the post-implantation factors. USPD represents a safe and effective treatment modality for AKI, although complications such as catheter malfunctions, leakage, and peritonitis were observed. Furthermore, USPD demonstrated efficacy in managing CKD, although it was associated with a higher incidence of complications compared to conventional-start peritoneal dialysis. Despite its cost-effectiveness, PD requires greater technical expertise from medical professionals. Close supervision and pre-planning for catheter insertion are essential for CKD patients. Whenever feasible, an urgent start should be avoided. Nevertheless, in emergency scenarios, USPD does remain a safe and efficient approach.

Timing of Kidney Replacement Therapy among Children and Young Adults

BACKGROUND

No randomized trials exist to guide the timing of the initiation of KRT in children. We sought to define trends and predictors of the eGFR at initiation of KRT, center-related clinical practice variation, and any association with patient survival.

METHODS

Children and young adults (1-25 years) commencing KRT (dialysis or kidney transplantation) between 1995 and 2018 were included using data from the Australia and New Zealand Dialysis and Transplant Registry. The associations between eGFR on commencing KRT and covariates were estimated using quantile regression. Cox regression was used to estimate the association between eGFR and patient survival. Logistic regression, categorizing eGFR about a value of 10 ml/min per 1.73 m 2 , was used in conjunction with a random effect by center to quantify clinical practice variation.

RESULTS

Overall, 2274 participants were included. The median eGFR at KRT initiation increased from 7 to 9 ml/min per 1.73 m 2 over the study period and the 90th centile from 11 to 17 ml/min per 1.73 m 2 . The effect of era on median eGFR was modified by modality, with a greater increase among those receiving a preemptive kidney transplant (1.0 ml/min per 1.73 m 2 per 5 years; 95% confidence interval [CI], 0.6 to 1.5) or peritoneal dialysis (0.7 ml/min per 1.73 m 2 per 5 years; 95% CI, 0.4 to 0.9) compared with hemodialysis (0.1 ml/min per 1.73 m 2 per 5 years; 95% CI, -0.1 to 0.3). There were 252 deaths (median follow-up 8.5 years, interquartile range 3.7-14.2) and no association between eGFR and survival (hazard ratio, 1.01 per ml/min per 1.73 m 2 ; 95% CI, 0.98 to 1.04). Center variation explained 6% of the total variance in the odds of initiating KRT earlier. This rose to over 10% when comparing pediatric centers alone.

CONCLUSIONS

Children and young adults progressively commenced KRT earlier. This change was more pronounced for children starting peritoneal dialysis or receiving a preemptive kidney transplant. Earlier initiation of KRT was not associated with any difference in patient survival. A substantial proportion of clinical practice variation was due to center variation alone.

PODCAST

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Cancer Mortality in People Receiving Dialysis for Kidney Failure: An Australian and New Zealand Cohort Study, 1980-2013

RATIONALE & OBJECTIVE

Cancer is a significant cause of morbidity in the population with kidney failure; however, cancer mortality in people undergoing dialysis has not been well described. We sought to compare cancer mortality in people on dialysis for kidney failure with cancer mortality in the general population.

STUDY DESIGN

A retrospective cohort study using linked health-administrative and dialysis registry data.

SETTING & PARTICIPANTS

All people receiving dialysis represented in the Australian and New Zealand Dialysis and Transplantation Registry, 1980-2013.

EXPOSURE

Dialysis; hemodialysis (HD) and peritoneal dialysis (PD).

OUTCOME

Death and underlying cause of death ascertained using health administrative data and classified using International Classification of Diseases, Tenth Revision, Australian Modification (ICD-10-AM) codes.

ANALYTICAL APPROACH

Indirect standardization on age at death, sex, year, and country to estimate standardized mortality ratios (SMR).

RESULTS

Over 269,598 person years of observation, 34,100 deaths occurred among 59,648 people on dialysis, including 3,677 cancer deaths. The relative risk of all-site cancer death in dialysis was twice (SMR, 2.4 [95% CI, 2.33-2.49]) that of the general population and highest for oral and pharynx cancers (SMR, 24.3 [95% CI, 18.0-31.5]) and multiple myeloma (SMR, 22.5 [95% CI, 20.3-23.9]). Women on dialysis had a significantly higher risk of all-site cancer mortality (SMR, 2.7 [95% CI, 2.59-2.89]) compared with men (SMR, 2.3 [95% CI, 2.17-2.36]) (P < 0.001). People on HD (SMR, 2.2 [95% CI, 2.11-2.30]) experienced greater excess deaths from all-site cancer compared with people on PD (SMR, 1.3 [95% CI, 1.23-1.44]). Excess deaths have gradually decreased over time for all-site, multiple myeloma, and kidney cancers (P < 0.001) but have not kept up with improvements in the general population. By contrast, among people receiving dialysis, excess deaths increased for colorectal and lung cancers (P < 0.001).

LIMITATIONS

Confirmation of cancer diagnoses and population incidence data were not available; inability to exclude pre-existing cancers.

CONCLUSIONS

People on dialysis experience excess all-site and site-specific cancer mortality compared with the general population. Mortality differs by modality type, age, and sex. Understanding the role of kidney failure and other morbidities in the treatment of cancer is important for shared decision-making regarding cancer treatments and identifying potential approaches to improve outcomes.

Epidemiology of pediatric chronic kidney disease/kidney failure: learning from registries and cohort studies

Although the concept of chronic kidney disease (CKD) in children is similar to that in adults, pediatric CKD has some peculiarities, and there is less evidence and many factors that are not clearly understood. The past decade has witnessed several additional registry and cohort studies of pediatric CKD and kidney failure. The most common underlying disease in pediatric CKD and kidney failure is congenital anomalies of the kidney and urinary tract (CAKUT), which is one of the major characteristics of CKD in children. The incidence/prevalence of CKD in children varies worldwide. Hypertension and proteinuria are independent risk factors for CKD progression; other factors that may affect CKD progression are primary disease, age, sex, racial/genetic factors, urological problems, low birth weight, and social background. Many studies based on registry data revealed that the risk factors for mortality among children with kidney failure who are receiving kidney replacement therapy are younger age, female sex, non-White race, non-CAKUT etiologies, anemia, hypoalbuminemia, and high estimated glomerular filtration rate at dialysis initiation. The evidence has contributed to clinical practice. The results of these registry-based studies are expected to lead to new improvements in pediatric CKD care.

Structural brain abnormalities in children and young adults with severe chronic kidney disease

BACKGROUND

The pathophysiology of neurological dysfunction in severe chronic kidney disease (CKD) in children and young adults is largely unknown. We aimed to investigate brain volumes and white matter integrity in this population and explore brain structure under different treatment modalities.

METHODS

This cross-sectional study includes 24 patients with severe CKD (eGFR < 30) aged 8-30 years (median = 18.5, range = 9.1-30.5) on different therapy modalities (pre-dialysis, n = 7; dialysis, n = 7; transplanted, n = 10) and 21 healthy controls matched for age, sex, and parental educational level. Neuroimaging targeted brain volume using volumetric analysis on T1 scans and white matter integrity with tract-based spatial statistics and voxel-wise regression on diffusion tensor imaging (DTI) data.

RESULTS

CKD patients had lower white matter integrity in a widespread cluster of primarily distal white matter tracts compared to healthy controls. Furthermore, CKD patients had smaller volume of the nucleus accumbens relative to healthy controls, while no evidence was found for abnormal volumes of gray and white matter or other subcortical structures. Longer time since successful transplantation was related to lower white matter integrity. Exploratory analyses comparing treatment subgroups suggest lower white matter integrity and smaller volume of the nucleus accumbens in dialysis and transplanted patients relative to healthy controls.

CONCLUSIONS

Young CKD patients seem at risk for widespread disruption of white matter integrity and to some extent smaller subcortical volume (i.e., nucleus accumbens). Especially patients on dialysis therapy and patients who received a kidney transplant may be at risk for disruption of white matter integrity and smaller volume of the nucleus accumbens.

Association of early initiation of dialysis with all-cause and cardiovascular mortality: A propensity score weighted analysis of the United States Renal Data System

BACKGROUND

Early initiation of maintenance hemodialysis has been associated with excess mortality in some studies, but the effects on cardiovascular (CV) mortality has not been studied. Moreover, whether the increased mortality is due to co-morbidities or early initiation of dialysis is unclear. We used a propensity score weighted analysis of the United States Renal Data System (USRDS) to examine how the estimated glomerular filtration rate (eGFR) at initiation of dialysis affects total and CV mortality.

METHODS

Association between tertiles of eGFR at initiation of hemodialysis and all-cause and CV mortality were assessed in 676,196 adult patients who initiated hemodialysis between 2006 and 2014, using inverse probability of treatment weighting (IPTW) weighted multivariable regression models.

RESULTS

The intermediate (eGFR 8.7 to <13.0 mL/min) and early start groups (eGFR ≥13.0 mL/min) had a 42% and 93% increased all-cause mortality, respectively compared to late (eGFR < 8.7), start group (unadjusted hazard ratio (HR) = 1.42; 95% CI, 1.41-1.43 and HR = 1.93; 95%CI, 1.91-1.94, respectively). This association was attenuated but remained significant in propensity weighted multivariable analysis (adjusted HR = 1.13; 95%CI, 1.12-1.14 for intermediate and HR = 1.37; 95%CI, 1.36-1.39, for early start, respectively). The CV mortality was similarly increased (adjusted HR = 1.08; 95%CI, 1.07-1.10 and HR = 1.23; 95%CI, 1.21-1.24, for intermediate and early start, respectively). In patients with cystic kidney disease, all-cause mortality was increased with early start, but there were no differences in CV mortality between groups.

CONCLUSIONS

Early initiation of dialysis is associated with increased all-cause and CV mortality. Our observations support delaying hemodialysis according to the eGFR values.

Early initiation of PD therapy in elderly patients is associated with increased risk of death

Background

The effect of early initiation of dialysis on outcomes of patients with end-stage renal disease (ESRD) remains controversial. We conducted this study to investigate the association between the timing of peritoneal dialysis (PD) initiation and mortality in different age groups.

Methods

In this single-centre cohort study, incident patients receiving PD from 1 January 2006 to 31 December 2016 were enrolled. Patients were categorized into three groups according to the estimated glomerular filtration rate (eGFR) at the initiation of PD, with early, mid and late initiation of PD defined as eGFR ≥7.5, 5–7.5 and <5 mL/min/1.73 m², respectively.

Results

A total of 2133 incident patients receiving PD were enrolled with a mean age of 47.1 years, 59.6% male and 25.3% with diabetes, of whom 1803 were young (age <65 years) and 330 were elderly (age ≥65 years). After multivariable adjustment, the overall and cardiovascular (CV) mortality risks for young patients receiving PD were not significantly different between these three groups. However, for elderly patients, early initiation of PD therapy was associated with increased risks of all-cause {hazard ratio [HR} 1.54 [95% confidence interval (CI) 1.06–2.25]} and CV [HR 2.07 (95% CI 1.24–3.48)] mortality compared with late initiation of PD, while no significant difference was observed in overall or CV mortality between the mid- and late-start groups.

Conclusions

No significant difference in mortality risk was found among the three levels of eGFR at PD therapy initiation in young patients, while early initiation of PD was associated with a higher risk of overall and CV mortality among elderly patients.

Should we abandon GFR in the decision to initiate chronic dialysis?

The best time to start chronic dialysis during the course of CKD stage 5 is controversial. The first randomised control trial of dialysis initiation either in early or late CKD stage 5 in adults (IDEAL study), and 3 studies from the two largest paediatric registries, the U.S. Renal Data System (USRDS) and the European Society of Paediatric Nephrology (ESPN) Registry, have now provided us with evidence to guide us in this important decision-making process. The message 'no benefit from early start of dialysis' is the conclusion from all four studies. However, what are the limitations of these studies? Can GFR be assessed at CKD stages 4 and 5? What are the factors used to assess the benefit of early or late start? These issues are discussed in this review.

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.

Controlling Nutritional Status (CONUT) score as immune-nutritional predictor of outcomes in patients undergoing peritoneal dialysis

BACKGROUND & AIMS

The Controlling Nutritional Status (CONUT) score was designed to assess the immune-nutritional status in patients. The aim of this study was to investigate the prognostic value of the CONUT score at the commencement of peritoneal dialysis (PD) for all-cause mortality, cardiovascular disease (CVD), and technique failure.

METHODS

This is a STROBE-compliant, retrospective, observational, single center study. A total of 252 patients with end stage renal disease initially undergoing PD were enrolled in the study. Baseline data were collected from The Third Affiliated Hospital of Soochow University Peritoneal Dialysis database. The primary outcome during follow-up was all-cause mortality. The secondary outcomes were CVD and technique failure. Univariate and multivariate Cox regression analyses were performed to estimate the association between confounding factors and outcomes. The area under the curve represented the test discriminative power of CONUT score and relevant clinical parameters. The Kaplan-Meier curve was used to compare the outcomes of the patients according to the cut-off CONUT score.

RESULTS

During a median follow-up period of 1.9 years, 35 patients (13.9%) died, 38 (15.1%) experienced CVD events, 58 (23.0%) experienced technique failure. The high CONUT group (CONUT score > 3) had significantly higher all-cause mortality (p = 0.02), CVD prevalence (p < 0.01), and technique failure rates (p < 0.01) than the low CONUT group (CONUT score ≤ 3). The CONUT score was an independent predictor of all-cause mortality (hazard ratio [HR]: 1.565; 95% CI: 1.305-1.876; p < 0.001), CVD (HR: 1.346; 95% CI: 1.136-1.594; p = 0.001), and technique failure (HR: 1.144; 95% CI: 1.006-1.302; p = 0.041).

CONCLUSION

The CONUT score is a straightforward and inexpensive indicator to evaluate the immune-nutritional status; it could be a reliable prognostic marker of all-cause mortality, CVD, and technique failure risk in patients undergoing PD.

Higher eGFR at Dialysis Initiation Is Not Associated with a Survival Benefit in Children

BACKGROUND

Study findings suggest that initiating dialysis at a higher eGFR level in adults with ESRD does not improve survival. It is less clear whether starting dialysis at a higher eGFR is associated with a survival benefit in children with CKD.

METHODS

To investigate this issue, we performed a retrospective cohort study of pediatric patients aged 1-18 years who, according to the US Renal Data System, started dialysis between 1995 and 2015. The primary predictor was eGFR at the time of dialysis initiation, categorized as higher (eGFR>10 ml/min per 1.73 m²) versus lower eGFR (eGFR≤10 ml/min per 1.73 m²).

RESULTS

Of 15,170 children, 4327 (29%) had a higher eGFR (median eGFR, 12.8 ml/min per 1.73 m²) at dialysis initiation. Compared with children with a lower eGFR (median eGFR, 6.5 ml/min per 1.73 m²), those with a higher eGFR at dialysis initiation were more often white, girls, underweight or obese, and more likely to have GN as the cause of ESRD. The risk of death was 1.36 times higher (95% confidence interval, 1.24 to 1.50) among children with a higher (versus lower) eGFR at dialysis initiation. The association between timing of dialysis and survival differed by treatment modality-hemodialysis versus peritoneal dialysis (P<0.001 for interaction)-and was stronger among children initially treated with hemodialysis (hazard ratio, 1.56, 95% confidence interval, 1.39 to 1.75; versus hazard ratio, 1.07, 95% confidence interval, 0.91 to 1.25; respectively).

CONCLUSIONS

In children with ESRD, a higher eGFR at dialysis initiation is associated with lower survival, particularly among children whose initial treatment modality is hemodialysis.