Determinants of eGFR at start of renal replacement therapy in paediatric patients

Timing and Modality of Kidney Replacement Therapy in Children and Adolescents

Introduction

The choice and timing of kidney replacement therapy (KRT) is influenced by clinical factors, laboratory features, feasibility issues, family preferences, and clinicians' attitudes. We analyzed the factors associated with KRT modality and timing in a multicenter, multinational prospective pediatric cohort study.

Methods

A total of 695 pediatric patients with chronic kidney disease (CKD) enrolled into the Cardiovascular Comorbidity in Children with CKD (4C) study at age 6 to 17 years with estimated glomerular filtration rate (eGFR) of 10 to 60 ml/min per 1.73 m2 were investigated. Competing risk regression was performed to identify factors associated with initiation of dialysis or preemptive transplantation (Tx), including primary renal diagnosis, demographics, anthropometrics, and laboratory parameters.

Results

During the 8-year observation period, 342 patients (49%) started KRT. Of these, 200 patients started dialysis, whereas 142 patients underwent preemptive Tx. A lower eGFR at enrolment (Hazard ratio [HR]: 0.76 [95% confidence interval: 0.74-0.78]), a steeper eGFR slope (HR: 0.90 [0.85-0.95], and a higher systolic blood pressure SD score (SDS) (HR: 2.07 [1.49-2.87]) increased the likelihood of KRT initiation. Patients with glomerulopathies were more likely to start dialysis than children with congenital anomalies of the kidneys and urinary tracts (CAKUT) (HR: 3.81 [2.52-5.76]). Lower body mass index (BMI) SDS (HR: 0.73 [0.6-0.89]) and lower hemoglobin (HR: 0.8 [0.72-0.9]) were associated with higher likelihood of dialysis. A significant center effect was observed, accounting for 6.8% (dialysis) to 8.7% (preemptive Tx) of explained variation.

Conclusion

The timing and choice of KRT in pediatric patients is influenced by the rate of kidney function loss, the underlying kidney disease, nutritional status, blood pressure, anemia and center-specific factors.

Development of an adaptive clinical web-based prediction tool for kidney replacement therapy in children with chronic kidney disease

Clinicians need improved prediction models to estimate time to kidney replacement therapy (KRT) for children with chronic kidney disease (CKD). Here, we aimed to develop and validate a prediction tool based on common clinical variables for time to KRT in children using statistical learning methods and design a corresponding online calculator for clinical use. Among 890 children with CKD in the Chronic Kidney Disease in Children (CKiD) study, 172 variables related to sociodemographics, kidney/cardiovascular health, and therapy use, including longitudinal changes over one year were evaluated as candidate predictors in a random survival forest for time to KRT. An elementary model was specified with diagnosis, estimated glomerular filtration rate and proteinuria as predictors and then random survival forest identified nine additional candidate predictors for further evaluation. Best subset selection using these nine additional candidate predictors yielded an enriched model additionally based on blood pressure, change in estimated glomerular filtration rate over one year, anemia, albumin, chloride and bicarbonate. Four additional partially enriched models were constructed for clinical situations with incomplete data. Models performed well in cross-validation, and the elementary model was then externally validated using data from a European pediatric CKD cohort. A corresponding user-friendly online tool was developed for clinicians. Thus, our clinical prediction tool for time to KRT in children was developed in a large, representative pediatric CKD cohort with an exhaustive evaluation of potential predictors and supervised statistical learning methods. While our models performed well internally and externally, further external validation of enriched models is needed.

Barriers to pre-emptive kidney transplantation in New Zealand children

AIM

Pre-emptive kidney transplantation (PKT) is generally considered the optimal treatment for kidney failure as it minimises dialysis-associated morbidity and mortality and is associated with improved allograft survival. This study aimed to determine rates of paediatric PKT in New Zealand, identify barriers to PKT and consider potential interventions to influence future rates of pre-emptive transplantation.

METHODS

Children commencing kidney replacement therapy between 2005 and 2017 in New Zealand were included. Descriptive analysis considered those referred late (referral <3 months prior to kidney replacement therapy initiation) or early based on referral timing to paediatric nephrology. Additional analysis compared characteristics of children receiving dialysis versus pre-emptive transplant as their first mode of kidney replacement therapy.

RESULTS

PKT occurred in 15 of 90 children (17%). One-third of all patients were referred late. No late referrals received a pre-emptive transplant. Pre-emptively transplanted children were referred younger (median age 0.49 years), lived in less deprived areas, were more likely to have congenital anomalies of the kidney and urinary tract and none were Māori or Pasifika ethnicity.

CONCLUSIONS

Late referral, higher deprivation levels and Māori and Pasifika ethnicity confer a greater risk of not receiving pre-emptive transplantation. Improved education amongst health professionals about recognition of paediatric chronic kidney disease and the importance of timely referral to paediatric nephrology is recommended to reduce rates of late referral. A modified approach including enhanced culturally appropriate support for those diagnosed with chronic kidney disease during transplant evaluation should be pursued to improve equity.

Preemptive Kidney Transplantation is Associated With Transplantation Outcomes in Children: Results From the French Kidney Replacement Therapy Registry

BACKGROUND

Kidney transplantation (KT) is the optimal treatment for children with end-stage kidney disease (ESKD). The aim of this study was to evaluate the impact of PKT and of pretransplant dialysis duration on graft survival among French pediatric kidney transplant recipients.

METHODS

We analyzed all first pediatric kidney-only transplantations performed in France between 1993 and 2012. A Cox multivariable model was used to investigate the association of PKT and pretransplant dialysis time with the hazard of graft failure defined as death, return to dialysis or retransplant, whichever occurred first.

RESULTS

1911 patients were included, of which 380 (19.8%) received a PKT. Median time of follow-up was 7.0 years. PKT was associated with a 55% reduction of the hazard of graft failure at any time after KT compared to patients transplanted after dialysis (HR 0.45; 95%CI 0.33-0.62), after adjustment for recipient sex and age, primary kidney disease, donor age and type (living or deceased donor), number of HLA mismatches, cold ischemia time and year of transplantation. A reduction of the hazard of graft failure was found in PKT whatever the compared duration of dialysis, even when less than 6 months and whatever the dialysis modality. Results were similar in multiple sensitivity analyses.

CONCLUSIONS

In France, PKT among pediatric patients is associated with a better graft survival when compared to KT after dialysis, even when less than 6 months. Based on these findings, we suggest that PKT should be considered as the treatment of choice for children with ESKD.

The incidence of and risk factors for late presentation of childhood chronic kidney disease: A systematic review and meta-analysis

BACKGROUND

When detected early, inexpensive measures can slow chronic kidney disease progression to kidney failure which, for children, confers significant morbidity and impacts growth and development. Our objective was to determine the incidence of late presentation of childhood chronic kidney disease and its associated risk factors.

METHODS

We searched MEDLINE, Embase, PubMed, Web of Science, Cochrane Library and CINAHL, grey literature and registry websites for observational data describing children <21 years presenting to nephrology services, with reference to late presentation (or synonyms thereof). Independent second review of eligibility, data extraction, and risk of bias was undertaken. Meta-analysis was used to generate pooled proportions for late presentation by definition and investigate risk factors. Meta-regression was undertaken to explore heterogeneity.

RESULTS

Forty-five sources containing data from 30 countries were included, comprising 19,339 children. Most studies (37, n = 15,772) described children first presenting in kidney failure as a proportion of the chronic kidney disease population (mean proportion 0.43, 95% CI 0.34-0.54). Using this definition, the median incidence was 2.1 (IQR 0.9-3.9) per million age-related population. Risk associations included non-congenital disease and older age. Studies of hospitalised patients, or from low- or middle-income countries, that had older study populations than high-income countries, had higher proportions of late presentation.

CONCLUSIONS

Late presentation is a global problem among children with chronic kidney disease, with higher proportions seen in studies of hospitalised children or from low/middle-income countries. Children presenting late are older and more likely to have non-congenital kidney disease than timely presenting children. A consensus definition is important to further our understanding and local populations should identify modifiable barriers beyond age and disease to improve access to care.

Setting reasonable objectives for improving preemptive kidney transplantation rates in children

BACKGROUND

This study aims to develop a method to estimate the potential of preemptive kidney transplantation (PKT) by identifying patients who were transplanted after a dialysis period (non-preemptive kidney transplantation (NPKT)) despite being medically suitable for PKT.

METHODS

All children (< 18 years old) starting kidney replacement therapy (KRT) in France, between 2010 and 2016 and transplanted before December 31, 2017, were included. A propensity score (PS) of receiving PKT was estimated by multivariate logistic regression based on recipient medical characteristics. Healthcare use during the 24 months prior to KRT initiation was extracted from the French National Health Insurance database, and a pre-KRT follow-up of more than 18 months was considered sufficient to allow preemptive transplantation.

RESULTS

Among 643 patients who started KRT, 149 (23.2%) were preemptively transplanted. Using PS stratification, among 391 NPKT patients, we identified 145 patients (37%) suitable for PKT, according to clinical characteristics. Mean age was 12.3 years, 67% were males, and 56% had urological abnormalities. Among those 145 patients, we identified 79 NPKT patients who started on dialysis despite early referral to a nephrologist (more than 18 months prior to KRT initiation).

CONCLUSIONS

This method estimates a potential of 228 (149 + 79) PKT (35%) among pediatric patients in France. A similar method could be used in adults or in other countries. Estimation of the rate of patients with CKD stage 5 medically suitable for PKT will be of interest for health policy makers when setting up objectives for improvement in preemptive kidney transplant access.

Growth Patterns After Kidney Transplantation in European Children Over the Past 25 Years: An ESPN/ERA-EDTA Registry Study

BACKGROUND

Improved management of growth impairment might have resulted in less growth retardation after pediatric kidney transplantation (KT) over time. We aimed to analyze recent longitudinal growth data after KT in comparison to previous eras, its determinants, and the association with transplant outcome in a large cohort of transplanted children using data from the European Society for Paediatric Nephrology/European Renal Association and European Dialysis and Transplant Association Registry.

METHODS

A total of 3492 patients transplanted before 18 years from 1990 to 2012 were included. Height SD scores (SDS) were calculated using recent national or European growth charts. We used generalized equation models to estimate the prevalence of growth deficit and linear mixed models to calculate adjusted mean height SDS.

RESULTS

Mean adjusted height post-KT was -1.77 SDS. Height SDS was within normal range in 55%, whereas 28% showed moderate, and 17% severe growth deficit. Girls were significantly shorter than boys, but catch-up growth by 5 years post-KT was observed in both boys and girls. Children <6 years were shortest at KT and showed the greatest increase in height, whereas there was no catch-up growth in children transplanted >12.

CONCLUSIONS

Catch-up growth post-KT remains limited, height SDS did not improve over time, resulting in short stature in nearly half of transplanted children in Europe.

Factors influencing the timing of initiation of renal replacement therapy and choice of modality in children with end-stage kidney disease

BACKGROUND

Decision-making in pediatric end-stage renal disease (ESRD) is a complex process for patients, families, and physicians. We evaluated the factors influencing the timing of initiation of renal replacement therapy (RRT) and choice of modality in children with ESRD.

METHODS

We retrospectively reviewed the RRT decision-making process for all children up to 19 years of age with ESRD, who underwent RRT over an 11-year period (2004 to 2014), at a Canadian pediatric tertiary care center. RRT modalities included peritoneal dialysis (PD), hemodialysis (HD), pre-emptive kidney transplant (PKT), and continuous renal replacement therapy (CRRT).

RESULTS

Ninety-two patients progressed to ESRD. RRT was started electively for 58 patients, and urgently for 34 patients. For elective patients, modalities included PD (34%), HD (19%), and PKT (47%). The glomerular filtration rate at initiation of RRT was higher in patients who underwent PKT as opposed to dialysis (11.7 vs. 9.1 ml/min/1.73m²). Medical and quality of life factors, including fatigue and poor concentration, influenced the timing of initiation of elective RRT. Medical factors were primarily important in urgent RRT, including oligoanuria and metabolic disturbances. Medical factors, patient/family preference, and contextual factors such as location of residence influenced choice of modality.

CONCLUSIONS

Our study found that the decision-making process in ESRD is multifactorial and involves not only medical factors, but also assessment of social factors, quality of life, and patient/family preference. Bettering our understanding of this decision-making process will positively impact patients and families through more informed decision-making.

Association between timing of dialysis initiation and clinical outcomes in the paediatric population: an ESPN/ERA-EDTA registry study

BACKGROUND

There is no consensus regarding the timing of dialysis therapy initiation for end-stage kidney disease (ESKD) in children. As studies investigating the association between timing of dialysis initiation and clinical outcomes are lacking, we aimed to study this relationship in a cohort of European children who started maintenance dialysis treatment.

METHODS

We used data on 2963 children from 21 different countries included in the European Society of Pediatric Nephrology/European Renal Association-European Dialysis and Transplant Association Registry who started renal replacement therapy before 18 years of age between 2000 and 2014. We compared two groups according to the estimated glomerular filtration rate (eGFR) at start: eGFR ≥8 mL/min/1.73 m2 (early starters) and eGFR <8 mL/min/1.73 m2 (late starters). The primary outcomes were patient survival and access to transplantation. Secondary outcomes were growth and cardiovascular risk factors. Sensitivity analyses were performed to account for selection- and lead time-bias.

RESULTS

The median eGFR at the start of dialysis was 6.1 for late versus 10.5 mL/min/1.73 m2 for early starters. Early starters were older [median: 11.0, interquartile range (IQR): 5.7-14.5 versus 9.4, IQR: 2.6-14.1 years]. There were no differences observed between the two groups in mortality and access to transplantation at 1, 2 and 5 years of follow-up. One-year evolution of height standard deviation scores was similar among the groups, whereas hypertension was more prevalent among late initiators. Sensitivity analyses resulted in similar findings.

CONCLUSIONS

We found no evidence for a clinically relevant benefit of early start of dialysis in children with ESKD. Presence of cardiovascular risk factors, such as high blood pressure, should be taken into account when deciding to initiate or postpone dialysis in children with ESKD, as this affects the survival.

Clinical characteristics at the renal replacement therapy initiation of Japanese pediatric patients: a nationwide cross-sectional study

BACKGROUND

Although there is debate regarding the timing of initiation of renal replacement therapy (RRT) in adults with end-stage renal disease, there is a paucity of reliable epidemiological data on pediatric patients. The present study was performed to investigate current practice in Japan with regard to the timing of initiation of RRT in children based on estimated glomerular filtration rate (eGFR).

METHODS

A total of 649 pediatric patients < 20 years old with eGFR at the initiation of RRT between 1 January 2006 and 31 December 2013 were included in the study. Baseline eGFR was calculated for each patient using the Schwartz formula.

RESULTS

eGFR at the start of RRT was 12.1 mL/min/1.73 m² [interquartile range (IQR) 8.4-16.3]. A total of 209 children (32.2%) had high eGFR (eGFR > 15 mL/min/1.73 m²) at the initiation of RRT. Initiation of RRT was more likely in those undergoing preemptive transplantation (PEKT) with high eGFR [odds ratio (OR) 4.16; 95% confidence interval (CI) 1.95-8.90, P < 0.001]. There were 31 deaths of various causes during follow-up, with infections representing the leading causes of death.

CONCLUSIONS

The median eGFR at the initiation of RRT in children showed a wide range of variation. Further studies are needed to investigate the impact of the decision regarding when to initiate RRT in individual pediatric patients.

Estimated GFR at Dialysis Initiation and Mortality in Children and Adolescents

RATIONALE & OBJECTIVE

The association of estimated glomerular filtration rate (eGFR) at dialysis therapy initiation with mortality among adult dialysis patients has been greatly debated, with some studies showing no benefit from early dialysis therapy initiation. However, this association has not been well investigated in pediatric dialysis patients. The objective of this study was to evaluate the mortality risk associated with eGFR at dialysis therapy initiation in children and adolescents with kidney failure.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

9,963 incident dialysis patients aged 1 to 17 years in the US Renal Data System registry (1995-2016).

PREDICTOR

eGFRs at dialysis therapy initiation calculated using the pediatric-specific bedside Schwartz equation (<5, 5-<7, 7-<9, 9-<12, and ≥12mL/min/1.73m²).

OUTCOME

Time to all-cause death.

ANALYTICAL APPROACH

Cox proportional hazards regression adjusted for case-mix variables, height, body mass index, hemoglobin level, and serum albumin level.

RESULTS

Median eGFR was 7.8 (IQR, 5.6-10.5) mL/min/1.73m² and median age was 13 (IQR, 9-16) years. 696 deaths were observed during the median follow-up of 1.4 (IQR, 0.7-2.7) years, and overall crude mortality rate was 31 per 1,000 patient-years. There appeared to be a trend toward higher mortality risk across higher eGFRs at dialysis therapy initiation. Compared with eGFRs of 7 to <9mL/min/1.73m², eGFRs <5 and ≥12mL/min/1.73m² were associated with lower and higher mortality, with adjusted HRs of 0.57 (95% CI, 0.43-0.74) and 1.31 (95% CI, 1.05-1.65), respectively. In age-stratified analysis, there were consistent relationships among patients 6 years and older while the eGFR-mortality association was attenuated among patients younger than 6 years (P_interaction = 0.002).

LIMITATIONS

Possible errors in eGFRs due to methods for serum creatinine measurement. Unmeasured confounders related to eGFR at dialysis therapy initiation.

CONCLUSIONS

Higher eGFR at dialysis therapy initiation was associated with higher mortality risk. Further studies of eGFR at initiation are needed in pediatric dialysis patients, especially among those younger than 6 years.

Effect of the timing of dialysis initiation on left ventricular hypertrophy and ınflammation in pediatric patients

BACKGROUND

The optimal time for dialysis initiation in adults and children with chronic kidney disease remains unclear. The aim of this study was to evaluate the impact of dialysis timing on different outcome parameters, in particular left ventricular (LV) morphology and inflammation, in pediatric patients receiving peritoneal dialysis and hemodialysis.

METHODS

The medical records of pediatric dialysis patients who were followed-up in nine pediatric nephrology centers in Turkey between 2008 and 2013 were retrospectively reviewed. In addition to demographic data, we retrieved anthropometric measurements, data on dialysis treatment modalities, routine biochemical parameters, complete blood count, serum ferritin, parathormone, C-reactive protein (CRP), and albumin levels, as well as echocardiographic data and hospitalization records. The patients were divided into two groups based on their estimated glomerular filtration rate (eGFR) levels at dialysis initiation, namely, an early-start group, characterized by an eGFR of >10 ml/min/1.73 m², and a late-start group, with an eGFR of < 7 ml/min/1.73 m². The collected data were compared between these groups.

RESULTS

A total of 245 pediatric dialysis patients (mean age ± standard deviation 12.3 ± 5.1 years, range 0.5-21 years) were enrolled in this study. Echocardiographic data were available for 137 patients, and the mean LV mass index (LVMI) was 58 ± 31 (range 21-215) g/m^2.7. The LVMI was 75 ± 30 g/m^2.7(n = 81) and 34 ± 6 g/m^2.7(n = 56) in patients with or without LV hypertrophy (LVH) (p < 0.001). Early-start (eGFR >10 ml/min/1.73 m²) versus late-start dialysis (eGFR < 7 ml/min/1.73 m²) groups did not significantly differ in LVMI and LVH status (p > 0.05) nor in number of hospitalizations. Serum albumin levels were significantly higher in the early-dialysis group compared with the late-dialysis group (3.3 ± 0.7 vs. 3.1 ± 0.7 g/dl, respectively; p < 0.05). The early-start group had relatively higher time-averaged albumin levels (3.2 ± 0.5 vs. 3.1 ± 0.5 g/dl; p = > 0.05) and relatively lower CRP levels (3.64 ± 2.00 vs. 4.37 ± 3.28 mg/L, p > 0.05) than the late-start group, but these differences did not reach statistical significance.

CONCLUSION

Although early dialysis initiation did not have a significant effect on important clinical outcome parameters, including LVH, inflammatory state, and hospitalization, in our pediatric dialysis patients, this area of study deserves further attention.

Variation in estimated glomerular filtration rate at dialysis initiation in children

BACKGROUND

Data guiding the timing of dialysis initiation in children are limited. We sought to determine current practice and secular trends in Canada with respect to the timing of dialysis initiation in children based on estimated glomerular filtration rate (eGFR).

METHODS

This observational study included incident chronic dialysis patients aged ≤21 years identified from the Canadian Organ Replacement Register who started dialysis in Canada between January 2001 and December 2010 at any of the nine participating Canadian centers (n = 583). Youth were categorized utilizing CKiD Schwartz eGFR into ≥10.5 (higher) or <10.5 ml/min/1.73 m² (lower) eGFR groups. Differences at dialysis initiation by facility and region were examined, and secular trends were determined.

RESULTS

Median eGFR at dialysis initiation was 8.1 (interquartile range 5.4-11.0) ml/min/1.73 m². Overall, 29 % of the patients started dialysis with an eGFR of ≥10.5 ml/min/1.73 m². The proportion of children starting with higher eGFR increased from 27.3 % in 2001 to 35.4 % in 2010 (p = 0.04) and differed by treatment facility (12-70 %; p = 0.0001). Factors associated with higher eGFR at dialysis initiation in the adjusted regression model were female sex [odds ratio (OR) 1.48; 95 % confidence interval (CI) 1.02-2.14], genetic cause of end-stage kidney disease (OR 2.77; 95 % CI 1.37-5.58) and living ≥50 km from treatment facility (OR 1.47; 95 % CI 1.01-2.14).

CONCLUSIONS

One-third of the children were found to have initiated dialysis with an eGFR ≥10.5 ml/min/1.73 m², however significant practice variation exists with respect to timing of dialysis initiation by treatment facility. More data is required to evaluate the clinical implications of this practice variation.

Lessons learned from the ESPN/ERA-EDTA Registry

End-stage renal disease (ESRD) in children is a medically challenging condition. Due to its rarity and special features, methodologically sound collaborative studies are required. In 2007, a new European registry of pediatric renal replacement therapy (RRT), the ESPN/ERA-EDTA Registry, was launched. In recent years, the Registry has provided comprehensive data on incidence, prevalence, patient characteristics, RRT modalities, and mortality in pediatric ESRD, along with relevant insights into cardiovascular risk, anemia, nutrition and growth, transplantation outcomes, and rare diseases. In this review, we describe the study design and structure underlying the ESPN/ERA-EDTA Registry, summarize the major research findings from more than 20 publications, and discuss current limitations and the future challenges to overcome.

Perceptions of pediatric nephrologists regarding timing of dialysis initiation in children in Canada

BACKGROUND

Significant practice variation exists in Canada with respect to timing of dialysis initiation in children. In the absence of evidence to guide practice, physicians' perceptions may significantly influence decision-making.

OBJECTIVE

The objectives of this study are to (1) evaluate Canadian pediatric nephrologists' perceptions regarding dialysis initiation in children with chronic kidney disease (CKD) and (2) determine the factors guiding practice that may contribute to practice variation across Canada.

DESIGN

This study was a cross-sectional online survey.

SETTING

This study was done in academic pediatric nephrology centers in Canada.

PARTICIPANTS

The participants of this study are pediatric nephrologists.

MEASUREMENTS AND METHODS

An anonymous web-based survey was administered to pediatric nephrologists in Canada to evaluate perspectives and practice patterns regarding timing of dialysis initiation. We also explored the importance of estimated glomerular filtration rate (eGFR) vs. symptoms and the role of patient and provider factors influencing decisions.

RESULTS

Thirty-five nephrologists (59 %) completed the survey. Most respondents care for advanced CKD patients in a multidisciplinary clinic (86 %) and no centers have a formal policy on timing of dialysis initiation. Seventy-five percent of centers follow <20 stage 4-5 CKD patients, and 9 % follow >30 patients. Discussions about dialysis initiation are generally informal (75 %) and the decision to start is made by the nephrologist (37 %) or a team (57 %). Fifty percent agreed GFR was important when deciding when to initiate dialysis, 41 % were neutral, and 9 % disagreed. Variability exists in the threshold that nephrologists considered early (vs. late) dialysis initiation: >20 (21 %), >15 (38 %), >12 (26 %), and >10 ml/min/1.73 m(2) (12 %). Practitioners however typically start dialysis in asymptomatic patients at eGFRs of 7-9 (9 %), 10-11 (41 %), 12-14 (38 %), and 15-19 (6 %) ml/min/1.73 m(2). Patient factors important in the decision to start dialysis for >90 % of nephrologists were fatigue, >10 % weight loss, nausea, increasing missed school, and awaiting a pre-emptive transplant. Age was only a factor for 56 %.

LIMITATIONS

This study has a 59 % response rate.

CONCLUSIONS

Variability exists in Canada regarding the importance and threshold of eGFR guiding the decision as to when to start dialysis in children, whereas patient symptoms are almost universally important to pediatric nephrologists' decision-making. Additional studies evaluating outcomes of children starting dialysis earlier vs. later are needed to standardize decision-making and care for children with kidney failure.

Early Requirement for RRT in Children at Presentation in the United Kingdom: Association with Transplantation and Survival

BACKGROUND AND OBJECTIVES

We evaluated rates and factors associating with late referral (LR) and describe association of LR with access to renal transplantation and patient survival in children in the United Kingdom. Early requirement of RRT within 90 days of presentation to a pediatric nephrologist was classed as a LR, and those >90 days as an early referral (ER).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We included patients who commenced RRT, aged ≥3 months and <16 years, from 1996 to 2012.

RESULTS

Of 1603 patients, 25.5% (n=408) were LR, of which 75% commenced RRT in <30 days following presentation. Those with LR were more likely to be older at presentation, female, and black. The primary renal disease in LR was more likely to be glomerular disease (odds ratio [OR], 1.6; 95% confidence interval [95% CI], 1.12 to 2.29), renal malignancy and associated diseases (OR, 4.11; 95% CI, 1.57 to 10.72), tubulo-interstitial diseases (OR, 2.37; 95% CI, 1.49 to 3.78), or an uncertain renal etiology (OR, 5.75; 95% CI, 3.1 to 10.65). Significant differences in rates of transplantation between LR and ER remained up to 1-year following commencement of dialysis (21% versus 61%, P<0.001) but with no differences for donor source (33.3% and 35.3% living donor in LR and ER respectively, P=0.55). The median (interquartile range) follow-up time was 4.8 years (2.9-7.6). There were 55 deaths with no statistically significant difference in survival in the LR group compared with the ER group (hazard ratio, 1.30; 95% CI, 0.7 to 2.3; P=0.40).

CONCLUSIONS

We found that 25% of children starting RRT in the United Kingdom receive a LR to pediatric renal services, with little change observed over the past two decades. Those with LR are unable to benefit from pre-emptive transplantation and require longer periods of dialysis before transplantation. There is an urgent need to understand causes of avoidable LR and develop strategies to improve kidney awareness more widely among health care professionals looking after children.

Demographics of paediatric renal replacement therapy in Europe: a report of the ESPN/ERA-EDTA registry

BACKGROUND

The ESPN/ERA-EDTA Registry collects data on European children with end-stage renal disease receiving renal replacement therapy (RRT) who are listed on national and regional renal registries in Europe. In this paper we report on the analysis of demographic data collected from 2009 to 2011.

METHODS

Data on primary renal disease, incidence, prevalence, 4-year survival, transplantation rate and causes of death in paediatric patients receiving RRT were extracted from the ESPN/ERA-EDTA Registry for 37 European countries.

RESULTS

The incidence of RRT in paediatric patients in Europe during the study period was 5.5 cases per million age-related population (pmarp) in patients aged 0-14 years and varied markedly between countries (interquartile range 3.4-7.0 years). The prevalence of RRT was 27.9 pmarp and increased with age, with 67 % of prevalent patients living with a functioning graft. The probability of receiving a transplant within 4 years was 76.9 % and was lowest in patients aged 0-4 years (68.9 %). Mortality in paediatric patients treated with RRT was 55-fold higher than that of the general EU paediatric population. Overall survival at 4 years was 93.7 %, with the poorest survival in patients aged 0-4 years and in patients starting on dialysis. Infections (19.9 %) were the primary cause of death in European paediatric RRT patients.

CONCLUSION

Considerable variation exists in the current demographics of children treated with RRT across Europe.

Adult height in patients with advanced CKD requiring renal replacement therapy during childhood

BACKGROUND AND OBJECTIVES

Growth and final height are of major concern in children with ESRD. This study sought to describe the distribution of adult height of patients who started renal replacement therapy (RRT) during childhood and to identify determinants of final height in a large cohort of RRT children.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A total of 1612 patients from 20 European countries who started RRT before 19 years of age and reached final height between 1990 and 2011 were included. Linear regression analyses were performed to calculate adjusted mean final height SD score (SDS) and to investigate its potential determinants.

RESULTS

The median final height SDS was -1.65 (median of 168 cm in boys and 155 cm in girls). Fifty-five percent of patients attained an adult height within the normal range. Adjusted for age at start of RRT and primary renal diseases, final height increased significantly over time from -2.06 SDS in children who reached adulthood in 1990-1995 to -1.33 SDS among those reaching adulthood in 2006-2011. Older age at start of RRT, more recent period of start of RRT, cumulative percentage time on a functioning graft, and greater height SDS at initiation of RRT were independently associated with a higher final height SDS. Patients with congenital anomalies of the kidney and urinary tract and metabolic disorders had a lower final height than those with other primary renal diseases.

CONCLUSIONS

Although final height remains suboptimal in children with ESRD, it has consistently improved over time.

Disparities in policies, practices and rates of pediatric kidney transplantation in Europe

We aimed to provide an overview of kidney allocation policies related to children and pediatric kidney transplantation (KTx) practices and rates in Europe, and to study factors associated with KTx rates. A survey was distributed among renal registry representatives in 38 European countries. Additional data were obtained from the ESPN/ERA-EDTA and ERA-EDTA registries. Thirty-two countries (84%) responded. The median incidence rate of pediatric KTx was 5.7 (range 0-13.5) per million children (pmc). A median proportion of 17% (interquartile range 2-29) of KTx was performed preemptively, while the median proportion of living donor KTx was 43% (interquartile range 10-52). The median percentage of children on renal replacement therapy (RRT) with a functioning graft was 62%. The level of pediatric prioritization was associated with a decreased waiting time for deceased donor KTx, an increased pediatric KTx rate, and a lower proportion of living donor KTx. The rates of pediatric KTx, distribution of donor source and time on waiting list vary considerably between European countries. The lack of harmonization in kidney allocation to children raises medical and ethical issues. Harmonization of pediatric allocation policies should be prioritized.

Causes and outcome of late referral of children who develop end-stage kidney disease

AIMS

This study aims to characterise the timing of referral to a paediatric nephrology unit of children who develop end-stage kidney disease (ESKD). This study also aims to determine whether late referral (LR) influences outcomes and to explore factors that may lead to LR.

METHODS

A retrospective case review of all incident patients with ESKD who received renal replacement therapy (RRT) at a single paediatric centre. Time between referral to a paediatric nephrologist and commencement of RRT, demographic and clinical data were collated. Estimated glomerular filtration rate (eGFR) at referral was calculated using height and creatinine. LR was defined as having an eGFR ≤ 30 mL/min/1.73 m(2) when first seen by a paediatric nephrologist.

RESULTS

RRT was initiated for 74 patients < 18 years of age between 1988 and 2010. The median age at referral was 2.0 years (birth-15.9 years) and age at RRT was 10.0 years (6 days-17.4 years). Children referred before age 1 year (41%) had a more prolonged course before ESKD. Median (interquartile range) eGFR at referral of children > 1 year was 27.2 (9.0-52.0) mL/min/1.73 m(2) . Twenty-two (55%) of these children were referred late (LR) with an eGFR ≤ 30 mL/min/1.73 m(2) . LR patients were more likely to have glomerulonephritis or haemolytic uraemic syndrome and to live in a remote or outer regional area. LR patients had higher urea, lower haemoglobin and were more likely to receive haemodialysis via a vascular catheter.

CONCLUSIONS

A significant proportion of children who develop ESKD are referred late to nephrology units with potentially preventable complications. Aetiology of renal disease and geographic isolation contribute to LR.

Epidemiology of chronic kidney disease in children

In the past 30 years there have been major improvements in the care of children with chronic kidney disease (CKD). However, most of the available epidemiological data stem from end-stage renal disease (ESRD) registries and information on the earlier stages of pediatric CKD is still limited. The median reported incidence of renal replacement therapy (RRT) in children aged 0-19 years across the world in 2008 was 9 (range: 4-18) [corrected] per million of the age-related population). [corrected] The prevalence of RRT in 2008 ranged from 18 to 100 per million of the age-related population. Congenital disorders, including congenital anomalies of the kidney and urinary tract (CAKUT) and hereditary nephropathies, are responsible for about two thirds of all cases of CKD in developed countries, while acquired causes predominate in developing countries. Children with congenital disorders experience a slower progression of CKD than those with glomerulonephritis, resulting in a lower proportion of CAKUT in the ESRD population compared with less advanced stages of CKD. Most children with ESRD start on dialysis and then receive a transplant. While the survival rate of children with ERSD has improved, it remains about 30 times lower than that of healthy peers. Children now mainly die of cardiovascular causes and infection rather than from renal failure.

Characteristics and outcomes of children with primary oxalosis requiring renal replacement therapy

BACKGROUND AND OBJECTIVES

Primary hyperoxaluria (PH) as a cause of ESRD in children is believed to have poor outcomes. Data on management and outcomes of these children remain scarce.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study included patients aged <19 years who started renal replacement therapy (RRT) between 1979 and 2009 from 31 countries providing data to a large European registry.

RESULTS

Of 9247 incident patients receiving RRT, 100 patients had PH. PH children were significantly younger than non-PH children at the start of RRT. The median age at RRT of PH children decreased from 9.8 years in 1979-1989 to 1.5 years in 2000-2009. Survival was 86%, 79%, and 76% among PH patients at 1, 3, and 5 years after the start of RRT, compared with 97%, 94%, and 92% in non-PH patients, resulting in a three-fold increased risk of death over non-PH patients. PH and non-PH patient survival improved over time. Sixty-eight PH children received a first kidney (n=13) or liver-kidney transplantation (n=55). Although the comparison was hampered by the lower number of kidney transplantations primarily derived from the earlier era of RRT, kidney graft survival in PH patients was 82%, 79%, and 76% at 1, 3, and 5 years for liver-kidney transplantation and 46%, 28%, and 14% at 1, 3, and 5 years for kidney transplantation alone, compared with 95%, 90%, and 85% in non-PH patients.

CONCLUSIONS

The outcomes of PH children with ESRD are still poorer than in non-PH children but have substantially improved over time.

Characteristics and outcomes of children with primary oxalosis requiring renal replacement therapy

BACKGROUND AND OBJECTIVES

Primary hyperoxaluria (PH) as a cause of ESRD in children is believed to have poor outcomes. Data on management and outcomes of these children remain scarce.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study included patients aged <19 years who started renal replacement therapy (RRT) between 1979 and 2009 from 31 countries providing data to a large European registry.

RESULTS

Of 9247 incident patients receiving RRT, 100 patients had PH. PH children were significantly younger than non-PH children at the start of RRT. The median age at RRT of PH children decreased from 9.8 years in 1979-1989 to 1.5 years in 2000-2009. Survival was 86%, 79%, and 76% among PH patients at 1, 3, and 5 years after the start of RRT, compared with 97%, 94%, and 92% in non-PH patients, resulting in a three-fold increased risk of death over non-PH patients. PH and non-PH patient survival improved over time. Sixty-eight PH children received a first kidney (n=13) or liver-kidney transplantation (n=55). Although the comparison was hampered by the lower number of kidney transplantations primarily derived from the earlier era of RRT, kidney graft survival in PH patients was 82%, 79%, and 76% at 1, 3, and 5 years for liver-kidney transplantation and 46%, 28%, and 14% at 1, 3, and 5 years for kidney transplantation alone, compared with 95%, 90%, and 85% in non-PH patients.

CONCLUSIONS

The outcomes of PH children with ESRD are still poorer than in non-PH children but have substantially improved over time.

The effect of timing of the first kidney transplantation on survival in children initiating renal replacement therapy

BACKGROUND

Controversy exists concerning the timing of the first kidney transplantation for children who need to start renal replacement therapy (RRT). Our aim was to estimate the effect of timing of the first transplantation on patient survival in children, for the first time also taking into account the mortality on dialysis before transplantation.

METHODS

We included 2091 patients who started RRT between the age of 3 and 18 years in the period 1988-2007, from 13 European renal registries. A multistate model was used to simulate patient survival assuming (i) pre-emptive transplantation, (ii) transplantation after 1 or 2 years on dialysis and (iii) remaining on dialysis.

RESULTS

Over the 20-year period, the highest 8-year survival probabilities were achieved in children transplanted pre-emptively {living donor (LD): 95.9% [95% confidence interval (CI): 93.1-98.8], deceased donor (DD): 95.3% (95% CI: 90.9-99.9)} rather than after 2 years of dialysis [LD: 94.2% (95% CI: 91.6-96.8), DD: 93.4% (95% CI: 91.0-95.9)], although these differences were not statistically significant.

CONCLUSIONS

Even after taking mortality on dialysis into account, the potentially negative effect of postponing transplantation for 1 or 2 years was relatively small and not statistically significant. Therefore, if pre-emptive transplantation is not possible, starting RRT with a short period of dialysis and receiving a transplant thereafter seems an acceptable alternative from the perspective of patient survival.