Social Deprivation and Incidence of Pediatric Kidney Failure in France.

Introduction: Approximately 8 per million children and young adults aged < 20 years initiate kidney replacement therapy (KRT) per year in France. We hypothesize that social deprivation could be a determinant of childhood-onset kidney failure. The objective of this study was to estimate the incidence of pediatric KRT in France according to the level of social deprivation. Methods: All patients < 20 years who initiated KRT from 2010 to 2015 in metropolitan France were included. Data were collected from the comprehensive French registry of KRT French Renal Epidemiology and Information network (REIN). We used a validated ecological index to assess social deprivation, the 2011 French version of the European Deprivation Index (EDI). We estimated the age standardized incidence rates according to the quintiles of EDI using direct standardization and incidence rate ratio using Poisson regression. Results: We included 672 children with kidney failure (58.6% males, 30.7% with glomerular or vascular disease, 43.3% starting KRT between 11 and 17 years). 38.8% were from the most deprived areas (quintile 5 of EDI). The age standardized incidence rate increased with quintile of EDI, from 5.45 (95% confidence interval [CI] = 4.25-6.64) per million children per year in the least deprived quintile to 8.46 (95% CI = 7.41-9.51) in the most deprived quintile of EDI (incidence rates ratio Q5 vs. Q1 1.53-fold; 95% CI = 1.18-2.01). Conclusion: This study showed that even in a country with a universal health care system, there is a strong association between the incidence of pediatric KRT and social deprivation showing that social health inequalities appear from KRT initiation. This study highlights the need to look further into social inequalities in the earliest stage of chronic kidney disease (CKD).

Neonatal salt wasting syndrome: Aldosterone synthase deficiency caused by a new splicing variant in CYP11B2.

Aldosterone synthase deficiency (ASD) is a rare autosomal recessive disorder involving isolated aldosterone deficiency without any compromise of other adrenal hormones. This condition manifests mainly in the neonatal period and in infants as a salt wasting syndrome with vomiting and failure to thrive. Due to its potentially life-threatening effects, ASD requires a careful and early diagnosis based on appropriate hormonal investigations in order to initiate adequate management: rehydration as well as salt and fludrocortisone supplementation. Genetic analysis of the CYP11B2 gene will confirm ASD in most cases. We report the case of a newborn with a typical clinical presentation associated with some uncommon phenotypic features (hyperhidrosis, liver injury). Furthermore, our patient carries a new CYP11B2 splicing variant to be added to the approximately 60 pathogenic or likely pathogenic variants already reported.

Long-term Effects of Kidney Transplantation Compared With Dialysis on Intima-media Thickness in Children-Results From the 4C-T Study.

BACKGROUND: Children requiring kidney replacement therapy experience high burden of cardiovascular (CV) disease leading to increased mortality. Intima-media thickness (IMT) indicating atherosclerosis is a validated surrogate marker for future CV events. METHODS: We investigated the effect of different treatment modalities (dialysis, preemptive kidney transplantation (KTx), late KTx after dialysis) on IMT by multivariable linear mixed-effect modeling. Patients were enrolled in a prospective cohort study. RESULTS: A total of 261 analyzed children had a mean follow-up of 3 y. Children after preemptive and late KTx had lower levels of IMT when compared with dialysis. Using an interaction term, a significant progression of IMT over time was seen during dialysis (ß = 0.0053 mm/y, P   =  0.004). IMT before the start of therapy was the most influential determinant in all models. Low IMT was associated with maintenance steroid treatment after preemptive KTx. High IMT on dialysis was associated with higher systolic blood pressure, lower body mass index, lower serum albumin, and lower bicarbonate. CONCLUSIONS: IMT remained rather stable in children several years after KTx. In contrast, children on dialysis had higher IMT values, which increased over time. In these children, blood pressure control, calorie and protein intake, and acid-base homeostasis seem important. Taken together, children might profit from early transplantation to limit accumulation of CV risk.

Haemoglobin trajectories in chronic kidney disease and risk of major adverse cardiovascular events.

BACKGROUND: The trajectories of haemoglobin in patients with chronic kidney disease (CKD) have been poorly described. In such patients, we aimed to identify typical haemoglobin trajectory profiles and estimate their risks of major adverse cardiovascular events (MACE). METHODS: We used 5-year longitudinal data from the CKD-REIN cohort patients with moderate to severe CKD enrolled from 40 nationally representative nephrology clinics in France. A joint latent class model was used to estimate, in different classes of haemoglobin trajectory, the competing risks of (i) MACE + defined as the first event among cardiovascular death, non-fatal myocardial infarction, stroke or hospitalization for acute heart failure, (ii) initiation of kidney replacement therapy (KRT) and (iii) non-cardiovascular death. RESULTS: During the follow-up, we gathered 33 874 haemoglobin measurements from 3011 subjects (median, 10 per patient). We identified five distinct haemoglobin trajectory profiles. The predominant profile (n = 1885, 62.6%) showed an overall stable trajectory and low risks of events. The four other profiles had nonlinear declining trajectories: early strong decline (n = 257, 8.5%), late strong decline (n = 75, 2.5%), early moderate decline (n = 356, 11.8%) and late moderate decline (n = 438, 14.6%). The four profiles had different risks of MACE, while the risks of KRT and non-cardiovascular death consistently increased from the haemoglobin decline. CONCLUSION: In this study, we observed that two-thirds of patients had a stable haemoglobin trajectory and low risks of adverse events. The other third had a nonlinear trajectory declining at different rates, with increased risks of events. Better attention should be paid to dynamic changes of haemoglobin in CKD.

Decline in Left Ventricular Early Systolic Function with Worsening Kidney Function in Children with Chronic Kidney Disease: Insights from the 4C and HOT-KID Studies.

INTRODUCTION: Adults with childhood-onset chronic kidney disease (CKD) have an increased risk of cardiovascular disease. First-phase ejection fraction (EF1), a novel measure of early systolic function, may be a more sensitive marker of left ventricular dysfunction than other markers in children with CKD. OBJECTIVE: To examine whether EF1 is reduced in children with CKD. METHODS: Children from the 4C and HOT-KID studies were stratified according to estimated glomerular filtration rate (eGFR). The EF1 was calculated from the fraction of left ventricular (LV) volume ejected up to the time of peak aortic flow velocity. RESULTS: The EF1 was measured in children ages 10.9 ± 3.7 (mean ± SD) years, 312 with CKD and 63 healthy controls. The EF1 was lower, while overall ejection fraction was similar, in those with CKD compared with controls and decreased across stages of CKD (29.3% ± 3.7%, 23.5% ± 4.5%, 19.8% ± 4.0%, 18.5% ± 5.1%, and 16.7% ± 6.6% in controls, CKD 1, 2, 3, and ≥ 4, respectively, P < .001). The relationship of EF1 to eGFR persisted after adjustment for relevant confounders (P < .001). The effect size for association of measures of LV structure or function with eGFR (SD change per unit change in eGFR) was greater for EF1 (ß = 0.365, P < .001) than for other measures: LV mass index (ß = -0.311), relative wall thickness (ß = -0.223), E/e' (ß = -0.147), and e' (ß = 0.141) after adjustment for confounders in children with CKD. CONCLUSIONS: Children with CKD exhibit a marked and progressive decline in EF1 with falling eGFR. This suggests that EF1 is a more sensitive marker of LV dysfunction when compared to other structural or functional measures and that early LV systolic function is a key feature in the pathophysiology of cardiac dysfunction in CKD.

High Amino Acid Intake in Early Life Is Associated With Systolic but Not Diastolic Arterial Hypertension at 5 Years of Age in Children Born Very Preterm.

BACKGROUND: The life course of individuals born very premature is a topic of increasing concern. The association between high early amino acid intake and later high blood pressure (HBP) in preterm neonates is debated. METHODS AND RESULTS: In a national, prospective, population-based birth cohort, EPIPAGE-2 (Etude Epidémiologique sur Petits Ages Gestationnels), we assessed blood pressure at 5 years. Eligible infants were those born between 24 and 29 weeks of gestation. Infants were distributed in 2 groups of 717 infants matched on propensity score on whether or not they were exposed to high amino acid intake (>3.5 g/kg per day at day 7); 455 control term infants were also enrolled. A value ≥95th percentile of reference values for age and height defined systolic or diastolic HBP. Blood pressure at 5 years of age was assessed for 389 and 385 children in the exposed and nonexposed groups, respectively. Rates (in percent) of systolic and diastolic HBP were 18.0% (95% CI, 14.5%-22.2%), 13.3% (95% CI, 10.3%-17.0%), 8.5% (95% CI, 6.5%-11.1%), and 9.0% (95% CI, 6.6%-12.3%), 10.2% (95% CI, 7.5%-13.6%), and 5.4% (95% CI, 3.8%-7.6%) in exposed, nonexposed, and term-born groups, respectively. Exposure to high early amino acid intake and maximal serum creatinine (by 50 µmol/L) between day 3 and day 7 were 2 independent risk factors for systolic HBP (adjusted odds ratio [aOR], 1.60 [95% CI, 1.05-2.43] and aOR, 1.59 [95% CI, 1.12-2.26], respectively) but not for diastolic HBP (aOR, 0.84 [95% CI, 0.50-1.39] and aOR, 1.09 [95% CI, 0.71-1.67], respectively). After adjustment for 5-year weight Z score, the aOR between high early amino acid intake and systolic HBP was 1.50 [95% CI, 0.98-2.30]. CONCLUSIONS: These results suggest that mechanisms of childhood systolic HBP involve neonatal renal challenge by high amino acid intake or dysfunction.

Arteriovenous access creation and hazards of hospitalization and death in patients starting hemodialysis.

BACKGROUND: Recent evidence suggests overestimation of benefits associated with arteriovenous (AV) fistula versus graft in certain populations. We assessed hazards of all-cause and cause-specific hospitalization and death associated with AV access type in patients who started hemodialysis with a catheter in France, overall and by subgroups of age, sex, and comorbidities. METHODS: From the REIN Registry, we included patients who initiated hemodialysis with a catheter from 2010 through 2018, and identified first-created fistula or graft through the French national health-administrative database. We used joint frailty models to deal with recurrent hospitalizations and potential informative censoring by death, and inverse probability weighting to account for confounding. RESULTS: From the 18 800 patients included (mean age 68 ± 15 years, 35% women), 5% underwent AV graft creation first. Weighted hazard ratio (wHR) of all-cause hospitalization associated with graft was 1.08 (95% CI 1.02 to 1.15), that of vascular access-related hospitalization was 1.43 (95% CI 1.32 to 1.55), and those of cardiovascular- and infection-related hospitalizations were 1.14 (95% CI 1.03 to 1.26) and 1.11 (95% CI 0.97 to 1.28), respectively. Results were consistent for most subgroups, except that the highest hazard of all-cause, cardiovascular-, and infection- related hospitalizations with graft was blunted in patients with comorbidities (i.e. diabetes, wHR 1.01, 95% CI 0.93 -1.10; 1.10, 95% CI 0.96 to 1.26; and 0.94, 95% CI 0.78 to 1.12, respectively). CONCLUSIONS: In patients starting hemodialysis with a catheter, AV graft creation is associated with increased hazard of vascular access-related hospitalizations compared to fistula. This may not be the case for death or other causes of hospitalization.

Determinants of Kidney Failure in Primary Hyperoxaluria Type 1: Findings of the European Hyperoxaluria Consortium.

Introduction: Primary hyperoxaluria type 1 (PH1) has a highly heterogeneous disease course. Apart from the c.508G>A (p.Gly170Arg) AGXT variant, which imparts a relatively favorable outcome, little is known about determinants of kidney failure. Identifying these is crucial for disease management, especially in this era of new therapies. Methods: In this retrospective study of 932 patients with PH1 included in the OxalEurope registry, we analyzed genotype-phenotype correlations as well as the impact of nephrocalcinosis, urolithiasis, and urinary oxalate and glycolate excretion on the development of kidney failure, using survival and mixed model analyses. Results: The risk of developing kidney failure was the highest for 175 vitamin-B6 unresponsive ("null") homozygotes and lowest for 155 patients with c.508G>A and c.454T>A (p.Phe152Ile) variants, with a median age of onset of kidney failure of 7.8 and 31.8 years, respectively. Fifty patients with c.731T>C (p.Ile244Thr) homozygote variants had better kidney survival than null homozygotes (P = 0.003). Poor outcomes were found in patients with other potentially vitamin B6-responsive variants. Nephrocalcinosis increased the risk of kidney failure significantly (hazard ratio [HR] 3.17 [2.03-4.94], P < 0.001). Urinary oxalate and glycolate measurements were available in 620 and 579 twenty-four-hour urine collections from 117 and 87 patients, respectively. Urinary oxalate excretion, unlike glycolate, was higher in patients who subsequently developed kidney failure (P = 0.034). However, the 41% intraindividual variation of urinary oxalate resulted in wide confidence intervals. Conclusion: In conclusion, homozygosity for AGXT null variants and nephrocalcinosis were the strongest determinants for kidney failure in PH1.

REIN: a tool at the service of the paediatric patients / REIN : un outil au service des patients pédiatriques

On the occasion of the 20th anniversary of the REIN (French Renal Epidemiology and Information Network), a summary work on the contributions of the national French ESKD register was carried out. On the issue of paediatric CKD patients, the following key messages were retained. Paediatric stage 5 chronic kidney disease (CKD) has particularities that require to be analysed and taken into account because the mortality of these patients remains 30 times higher than that of children of the same age. The REIN registry enables illustrating the specificities of stage 5 CKD in the paediatric age-group in France and providing a set of indicators making it possible to describe the future of these patients as well as the choices made concerning the modalities of replacement therapy. As compared to other European countries, the incidence and prevalence of stage 5 CKD in France is in the middle range for children under 15 and 20 years old. Renal transplant is by far the leading treatment for stage 5 CKD in children and adolescents under 18 years of age in France, allowing to offer these patients the best possible life expectancy. Owing to the small volume of patients, only a nationwide registry can provide an unbiased view and enables analysing this population requiring a hyperspecialised treatment. The participation of French paediatric nephrologists in the REIN French registry also enables providing input to the European registry (ESPN/ERA www.espn-reg.org/index.jsp) and the international registry (IPNA https://ipna-registry.org) (Consulted on September 15th 2022) and thus the possibility of international studies, which are vital to be in line with an approach to improving practices.

À l'occasion des 20 ans du REIN (Réseau Epidémiologie et Information en Néphrologie), un travail de synthèse sur les apports du registre a été mené. Sur la question des patients pédiatriques, les messages clés suivants ont été retenus. La maladie rénale chronique (MRC) stade 5 pédiatrique a des particularités qui nécessitent d'être analysées et prises en compte car la mortalité de ces patients reste 30 fois supérieure à celle des enfants du même âge. Le registre REIN permet d'illustrer les spécificités de la MRC stade 5 à l'âge pédiatrique en France et de fournir un ensemble d'indicateurs permettant de décrire le devenir de ces patients ainsi que les choix faits concernant les modalités de traitement de suppléance. En comparaison à d'autres pays européens, l'incidence et la prévalence de la MRC stade 5 en France se situent dans les valeurs moyennes chez les enfants de moins de 15 et 20 ans. La transplantation rénale est de loin le premier traitement de la MRC stade 5 parmi les enfants et les adolescents de moins de 18 ans en France, permettant d'offrir à ces patients la meilleure espérance de vie possible. En raison du petit volume de patients, seul un registre à l'échelon national permet d'avoir une vision non biaisée et d'analyser cette population nécessitant une prise en charge hyperspécialisée. La participation des néphropédiatres français au registre français REIN permet aussi d'alimenter le registre européen (ESPN/ ERA www.espn-reg.org/index.jsp) et le registre international (IPNA https://ipna-registry.org) (Consulté le 15 septembre 2022) et ainsi la possibilité d'études internationales, indispensables pour s'inscrire dans une démarche d'amélioration des pratiques.

Stricter Blood Pressure Control Is Associated With Lower Left Ventricular Mass in Children After Kidney Transplantation: A Longitudinal Analysis of the 4C-T Study.

BACKGROUND: We assessed the effect of blood pressure (BP) control on left ventricular mass index (LVMI) and left ventricular hypertrophy (LVH). METHODS: Ninety-six patients (64 males) ≥9 months post-kidney transplantation from the 4C-T (Cardiovascular Comorbidity in Children with Chronic Kidney Disease and Transplantation) study were analyzed longitudinally (mean follow-up, 2.6±1.3 years). Cumulative systolic blood pressure (SBP)/diastolic BP exposure was calculated as a time-averaged area under the curve and categorized: ≤50th, 50th to ≤75th, 75th to ≤90th, and >90th percentile (pct). We performed adjusted linear and logistic mixed models for LVMI and LVH, respectively. RESULTS: At baseline, LVMI was 49.7±12.7g/m2.16 with 64% (n=61) kidney transplantation recipients displaying LVH. Compared with patients with cumulative SBP exposure >90th pct, patients with cumulative SBP of 50th to ≤75th showed a significant LVMI reduction of -5.24g/m2.16 (P=0.007). A similar tendency was seen for cumulative SBP≤50th (ß=-3.70 g/m2.16; P=0.067), but patients with cumulative SBP of 75th to ≤90th pct showed no reduction. A post hoc analysis in patients with cumulative SBP≤75th revealed that median SBP exposure was at 57.5th pct. For cumulative diastolic BP, a significant LVMI reduction was seen in all 3 categories ≤90th pct compared with patients >90th pct. Patients with cumulative SBP of ≤50th or 50th to ≤75th pct showed 79% or 83% lower odds of developing LVH, respectively. Patients with cumulative diastolic BP ≤50th showed a tendency of 82% lower odds for LVH (95% CI, 0.03-1.07). CONCLUSIONS: Stricter BP control led to regression of LVMI and LVH. Our data suggest a BP target below the 60th pct, which needs to be substantiated in a randomized controlled trial.

Efficacy and Safety of Eculizumab in Pediatric Patients Affected by Shiga Toxin-Related Hemolytic and Uremic Syndrome: A Randomized, Placebo-Controlled Trial.

SIGNIFICANCE STATEMENT: Shiga toxin-related hemolytic uremic syndrome (STEC-HUS) is a serious condition, characterized by multiorgan thrombotic microangiopathy, mainly affecting children. Renal involvement is severe, with approximately half of patients requiring dialysis. So far, no specific treatment has been proven efficient in STEC-HUS. The use of eculizumab, a monoclonal antibody inhibiting terminal complement complex, has demonstrated remarkable success in atypical hemolytic uremic syndrome, but its use in uncontrolled studies to treat STEC-HUS has yielded inconsistent results. In this Phase 3 randomized, placebo-controlled trial in 100 pediatric patients with STEC-HUS, the findings did not show efficacy of eculizumab during the acute phase of the disease. However, the results indicated a reduction of renal sequelae in eculizumab-treated patients at 1-year follow-up. Larger prospective studies would be needed to further explore eculizumab as a potential treatment. BACKGROUND: Shiga toxin-related hemolytic uremic syndrome (STEC-HUS) in children is a severe condition, resulting in approximately 50% of patients requiring RRT. Furthermore, at least 30% of survivors experience kidney sequelae. Recently, activation of the complement alternative pathway has been postulated as a factor in STEC-HUS pathophysiology, leading to compassionate use of eculizumab, a monoclonal antibody inhibiting the terminal complement complex, in affected patients. Given the lack of therapy for STEC-HUS, a controlled study of eculizumab efficacy in treating this condition is a priority. METHODS: We conducted a Phase 3 randomized trial of eculizumab in children with STEC-HUS. Patients were randomly assigned in a 1:1 ratio to receive either eculizumab or placebo during 4 weeks. Follow-up lasted for 1 year. The primary end point was RRT duration <48 hours after randomization. Secondary endpoints included hematologic and extrarenal involvement. RESULTS: Baseline characteristics were similar among the 100 patients who underwent randomization. The rate of RRT <48 hours did not differ significantly between the two groups (48% in the placebo versus 38% in the eculizumab group; P = 0.31) or in the course of ARF. The two groups also exhibited similar hematologic evolution and extrarenal manifestations of STEC-HUS. The proportion of patients experiencing renal sequelae at 1 year was lower in the eculizumab group than in the placebo group (43.48% and 64.44%, respectively, P = 0.04). No safety concern was reported. CONCLUSIONS: In pediatric patients with STEC-HUS, eculizumab treatment does not appear to be associated with improved renal outcome during acute phase of the disease but may reduce long-term kidney sequelae. CLINICAL TRIALS REGISTRATIONS: EUDRACT (2014-001169-28) ClinicalTrials.gov ( NCT02205541 ).

Outcome of children with IgA vasculitis with nephritis treated with steroids: a matched controlled study.

BACKGROUND: IgA vasculitis (IgAV) is the most common vasculitis in children. IgAV long-term prognosis depends on kidney involvement or IgA vasculitis with nephritis (IgAVN). To date, steroid treatment (oral steroids or methylprednisolone pulses) has not proven to be formally efficient. This study aimed to assess the role of steroids on IgAVN outcome. METHODS: All children with IgAVN diagnosed 2000-2019 in 14 French pediatric nephrology units with minimal follow-up of 6 months were retrospectively included. Outcomes of patients treated with steroids were compared with those of a control group of untreated patients matched for age, sex, proteinuria, eGFR, and histological features. The primary endpoint was IgAVN remission defined as urine protein-to-creatinine ratio < 20 mg/mmol without impaired eGFR one year after disease onset. RESULTS: A total of 359 patients with IgAVN were included with a median follow-up time of 249 days (range 43-809). One hundred eight (30%) patients received oral steroids alone, 207 (51%) patients received three methylprednisolone pulses followed by oral steroids, and 44 patients (12.5%) did not receive steroids. Thirty-two children treated with oral steroids alone were compared with 32 matched control patients who did not receive steroids. One year after disease onset, IgAVN remission proportion was not different between these two groups: 62% versus 68%, respectively. Ninety-three children treated with oral steroids alone were compared with 93 matched patients treated with three methylprednisolone pulses followed by oral corticosteroids. IgAVN remission proportion was not different between these two groups: 77% versus 73%, respectively. CONCLUSION: The benefit of oral steroids alone and methylprednisolone pulses could not be established based on this observational study. Randomized controlled trials are thus required to determine the efficacy of steroids in IgAVN. A higher resolution version of the Graphical abstract is available as Supplementary information.

Associations of longitudinal height and weight with clinical outcomes in pediatric kidney replacement therapy: results from the ESPN/ERA Registry.

BACKGROUND: Associations between anthropometric measures and patient outcomes in children are inconsistent and mainly based on data at kidney replacement therapy (KRT) initiation. We studied associations of height and body mass index (BMI) with access to kidney transplantation, graft failure, and death during childhood KRT. METHODS: We included patients < 20 years starting KRT in 33 European countries from 1995-2019 with height and weight data recorded to the ESPN/ERA Registry. We defined short stature as height standard deviation scores (SDS) < -1.88 and tall stature as height SDS > 1.88. Underweight, overweight and obesity were calculated using age and sex-specific BMI for height-age criteria. Associations with outcomes were assessed using multivariable Cox models with time-dependent covariates. RESULTS: We included 11,873 patients. Likelihood of transplantation was lower for short (aHR: 0.82, 95% CI: 0.78-0.86), tall (aHR: 0.65, 95% CI: 0.56-0.75), and underweight patients (aHR: 0.79, 95%CI: 0.71-0.87). Compared with normal height, patients with short and tall statures showed higher graft failure risk. All-cause mortality risk was higher in short (aHR: 2.30, 95% CI: 1.92-2.74), but not in tall stature. Underweight (aHR: 1.76, 95% CI: 1.38-2.23) and obese (aHR: 1.49, 95% CI: 1.11-1.99) patients showed higher all-cause mortality risk than normal weight subjects. CONCLUSIONS: Short and tall stature and being underweight were associated with a lower likelihood of receiving a kidney allograft. Mortality risk was higher among pediatric KRT patients with a short stature or those being underweight or obese. Our results highlight the need for careful nutritional management and multidisciplinary approach for these patients. A higher resolution version of the Graphical abstract is available as Supplementary information.

Disparities in treatment and outcome of kidney replacement therapy in children with comorbidities: an ESPN/ERA Registry study.

Background: Data on comorbidities in children on kidney replacement therapy (KRT) are scarce. Considering their high relevance for prognosis and treatment, this study aims to analyse the prevalence and implications of comorbidities in European children on KRT. Methods: We included data from patients <20 years of age when commencing KRT from 2007 to 2017 from 22 European countries within the European Society of Paediatric Nephrology/European Renal Association Registry. Differences between patients with and without comorbidities in access to kidney transplantation (KT) and patient and graft survival were estimated using Cox regression. Results: Comorbidities were present in 33% of the 4127 children commencing KRT and the prevalence has steadily increased by 5% annually since 2007. Comorbidities were most frequent in high-income countries (43% versus 24% in low-income countries and 33% in middle-income countries). Patients with comorbidities had a lower access to transplantation {adjusted hazard ratio [aHR] 0.67 [95% confidence interval (CI) 0.61-0.74]} and a higher risk of death [aHR 1.79 (95% CI 1.38-2.32)]. The increased mortality was only seen in dialysis patients [aHR 1.60 (95% CI 1.21-2.13)], and not after KT. For both outcomes, the impact of comorbidities was stronger in low-income countries. Graft survival was not affected by the presence of comorbidities [aHR for 5-year graft failure 1.18 (95% CI 0.84-1.65)]. Conclusions: Comorbidities have become more frequent in children on KRT and reduce their access to transplantation and survival, especially when remaining on dialysis. KT should be considered as an option in all paediatric KRT patients and efforts should be made to identify modifiable barriers to KT for children with comorbidities.

Urinary DKK3 as a biomarker for short-term kidney function decline in children with chronic kidney disease: an observational cohort study.

BACKGROUND: Childhood-onset chronic kidney disease is a progressive condition that can have a major effect on life expectancy and quality. We evaluated the usefulness of the kidney tubular cell stress marker urinary Dickkopf-related protein 3 (DKK3) in determining the short-term risk of chronic kidney disease progression in children and identifying those who will benefit from specific nephroprotective interventions. METHODS: In this observational cohort study, we assessed the association between urinary DKK3 and the combined kidney endpoint (ie, the composite of 50% reduction of the estimated glomerular filtration rate [eGFR] or progression to end-stage kidney disease) or the risk of kidney replacement therapy (ie, dialysis or transplantation), and the interaction of the combined kidney endpoint with intensified blood pressure reduction in the randomised controlled ESCAPE trial. Moreover, urinary DKK3 and eGFR were quantified in children aged 3-18 years with chronic kidney disease and urine samples available enrolled in the prospective multicentre ESCAPE (NCT00221845; derivation cohort) and 4C (NCT01046448; validation cohort) studies at baseline and at 6-monthly follow-up visits. Analyses were adjusted for age, sex, hypertension, systolic blood pressure SD score (SDS), BMI SDS, albuminuria, and eGFR. FINDINGS: 659 children were included in the analysis (231 from ESCAPE and 428 from 4C), with 1173 half-year blocks in ESCAPE and 2762 in 4C. In both cohorts, urinary DKK3 above the median (ie, >1689 pg/mg creatinine) was associated with significantly greater 6-month eGFR decline than with urinary DKK3 at or below the median (-5·6% [95% CI -8·6 to -2·7] vs 1·0% [-1·9 to 3·9], p<0·0001, in ESCAPE; -6·2% [-7·3 to -5·0] vs -1·5% [-2·9 to -0·1], p<0·0001, in 4C), independently of diagnosis, eGFR, and albuminuria. In ESCAPE, the beneficial effect of intensified blood pressure control was limited to children with urinary DKK3 higher than 1689 pg/mg creatinine, in terms of the combined kidney endpoint (HR 0·27 [95% CI 0·14 to 0·55], p=0·0003, number needed to treat 4·0 [95% CI 3·7 to 4·4] vs 250·0 [66·9 to ∞]) and the need for kidney replacement therapy (HR 0·33 [0·13 to 0·85], p=0·021, number needed to treat 6·7 [6·1 to 7·2] vs 31·0 [27·4 to 35·9]). In 4C, inhibition of the renin-angiotensin-aldosterone system resulted in significantly lower urinary DKK3 concentrations (least-squares mean 12 235 pg/mg creatinine [95% CI 10 036 to 14 433] in patients not on angiotensin-converting enzyme inhibitors or angiotensin 2 receptor blockers vs 6861 pg/mg creatinine [5616 to 8106] in those taking angiotensin-converting enzyme inhibitors or angiotensin 2 receptor blockers, p<0·0001). INTERPRETATION: Urinary DKK3 indicates short-term risk of declining kidney function in children with chronic kidney disease and might allow a personalised medicine approach by identifying those who benefit from pharmacological nephroprotection, such as intensified blood pressure lowering. FUNDING: None.

[Epidemiology of childhood chronic kidney diseases]. / Épidémiologie des maladies rénales chroniques en pédiatrie.

Major advances have been made in the management of children with chronic kidney disease (CKD) over the past 30 years. However, existing epidemiological data mainly relies on registries of chronic kidney replacement therapy. The incidence and prevalence of earlier stages of CKD remain largely unknown, but rare population-based studies suggest that the prevalence of all stages CKD may be as high as 1 % of the pediatric population. Congenital disorders including renal hypodysplasia and uropathy (CAKUT) and hereditary nephropathies account for one-half to two-thirds of childhood CKD cases in high-income countries, whereas acquired nephropathies predominate in developing countries. CKD progression is slower in children with congenital disorders than in those with glomerular nephropathy, and other risk factors for progression have also been identified. Children with CKD have poorer health-related quality of life when compared to healthy children. While survival of children with CKD has continuously improved over time, mortality remains 20 to 30 times higher than in the general pediatric population.

Title: Épidémiologie des maladies rénales chroniques en pédiatrie. Abstract: Au cours des trente dernières années, des progrès majeurs ont été réalisés dans la prise en charge des enfants souffrant d'une maladie rénale chronique (MRC). Cependant, les données épidémiologiques existantes proviennent essentiellement des registres de traitement de suppléance de l'insuffisance rénale terminale. L'incidence et la prévalence aux stades plus précoces de MRC restent donc mal connues, mais de rares études en population suggèrent que la prévalence de la MRC, tous stades confondus, pourrait concerner jusqu'à 1 % de la population pédiatrique. Les désordres congénitaux, incluant les hypodysplasies rénales et uropathies malformatives (CAKUT) et les néphropathies héréditaires, sont responsables de la moitié aux deux tiers des cas de MRC de l'enfant dans les pays industrialisés, alors que les néphropathies acquises prédominent dans les pays en développement. La progression de la MRC est plus lente chez les enfants avec une maladie congénitale que chez ceux ayant une néphropathie glomérulaire, et d'autres facteurs de risque de progression ont également été identifiés. Alors que la survie des enfants présentant une MRC s'est continuellement améliorée au cours du temps, la mortalité reste 20 à 30 fois supérieure à celle de la population générale pédiatrique.

Longitudinal uric acid has nonlinear association with kidney failure and mortality in chronic kidney disease.

We investigated the shape of the relationship between longitudinal uric acid (UA) and the hazard of kidney failure and death in chronic kidney disease (CKD) patients, and attempted to identify thresholds associated with increased hazards. We included CKD stage 3-5 patients from the CKD-REIN cohort with one serum UA measurement at cohort entry. We used cause-specific multivariate Cox models including a spline function of current values of UA (cUA), estimated from a separate linear mixed model. We followed 2781 patients (66% men, median age, 69 years) for a median of 3.2 years with a median of five longitudinal UA measures per patient. The hazard of kidney failure increased with increasing cUA, with a plateau between 6 and 10 mg/dl and a sharp increase above 11 mg/dl. The hazard of death had a U-shape relationship with cUA, with a hazard twice higher for 3 or 11 mg/dl, compared to 5 mg/dl. In CKD patients, our results indicate that UA above 10 mg/dl is a strong risk marker for kidney failure and death and that low UA levels below 5 mg/dl are associated with death before kidney failure.

Estimation of glomerular filtration rate in children: interest of FAS formula / Estimation du débit de filtration glomérulaire de l'enfant : intérêt de la formule FAS

The recommended equation to estimate the value of glomerular filtration rate (eGFR) among children is Schwartz equation updated in 2009. However, it is few frequently used because involves height, a factor rarely documented for laboratories, especially hospital laboratories. The FAS (Full Aged Spectrum) formula developed by a European group, allows to get away from this factor. We compared CKD-EPI (Chronic Kidney Disease-EPIdemiology collaboration) and FAS formulas to Schwartz equation to estimate GFR in children. We realized a retrospective study included 1.668 children between 2 and 14 years old, whose serum creatinine had been measured during their hospitalization stay. We showed that FAS formula is correlated to Schwartz (r = 0.88), with a mean underestimation of eGFR at 6.2% versus CKD-EPI which has a correlation coefficient equal to 0.45 and overestimates eGFR to approximatively 42.0% compared to Schwartz formula. Furthermore, concordance at 30% is 99% with FAS whereas it's only 35% with CKD-EPI. Thus, we recommend using the FAS formula to estimate GFR in children between 2 and 14 years old when their height is not available.

L'équation recommandée pour estimer le débit de filtration glomérulaire (DFG) chez l'enfant est la formule de Schwartz mise à jour en 2009. Cependant, celle-ci n'est pas toujours utilisée en routine, car elle fait intervenir la taille, un paramètre auquel les laboratoires, notamment hospitaliers, n'ont pas facilement accès. La formule FAS (Full Aged Spectrum), mise au point par un groupe européen, permet de s'affranchir de la taille de l'enfant. Nous avons comparé les résultats du DFG obtenus à partir des équations CKD-EPI (Chronic Kidney Disease-EPIdemiology collaboration) et FAS, aux valeurs obtenues avec la formule de Schwartz. Nous avons réalisé une étude rétrospective sur 1 668 enfants âgés entre 2 et 14 ans dont le dosage de la créatininémie avait été effectué durant l'hospitalisation. Nous avons montré que l'équation FAS est bien corrélée à celle de Schwartz (r = 0,88), avec une sous-estimation moyenne du DFG de 6,2 % versus CKD-EPI qui a un coefficient de corrélation égal à 0,45 et qui surestime le DFG d'environ 42 % par rapport à la formule de Schwartz. De plus, la concordance à 30 % est de 99 % pour FAS alors qu'elle n'est que de 35 % pour CKD-EPI. Ainsi, nous recommandons d'utiliser l'équation FAS pour estimer le DFG chez l'enfant entre 2 et 14 ans lorsque la taille n'est pas disponible.

Pediatric ANCA vasculitis: clinical presentation, treatment, and outcomes in a French retrospective study.

BACKGROUND: Pediatric ANCA vasculitis is a rare group of diseases with a scarcity of data in children. Annual incidence appeared to increase in the last several years, placing higher interest in the clinical and therapeutical outcomes of the disorder. Also, the growing use of rituximab questions the latest outcomes in these diseases. We therefore conducted a retrospective study to better understand the current characteristics, management, and the latest outcomes of the disorder. METHODS: We conducted a 9-year retrospective study of 46 children in 14 different centers across France to describe their clinical and laboratory presentations, therapeutic regimens, and kidney outcome. RESULTS: P-ANCA appeared to be a potential marker for higher relapse risk. Compared to adults, we found that ear-nose-throat presentations were frequent (45.7%) and more severe. Despite an evolution in the treatment management, kidney outcome remained poor with a substantial proportion of chronic kidney disease (54.8% at 1 year). Mortality stays low with 3 patients (6.5%) deceased at the end of our study. CONCLUSION: Clinical presentation was as previously described and time to diagnosis remains long. P-ANCA is a statistically significant marker for increased relapse risk. We observed a modification in the treatment regimens over the past several years with a growing use of rituximab and a decreasing use of cyclophosphamide. Despite these changes, kidney outcome remains poor and prospective studies should be conducted to assess the most appropriate therapeutic modality for each patient. A higher resolution version of the Graphical abstract is available as Supplementary information.