Diagnosis and management of primary hyperoxalurias: best practices.

The primary hyperoxalurias (PH 1, 2, and 3) are rare autosomal recessive disorders of glyoxylate metabolism resulting in hepatic overproduction of oxalate. Clinical presentations that should prompt consideration of PH include kidney stones, nephrocalcinosis, and kidney failure of unknown etiology, especially with echogenic kidneys on ultrasound. PH1 is the most common and severe of the primary hyperoxalurias with a high incidence of kidney failure as early as infancy. Until the recent availability of a novel RNA interference (RNAi) agent, PH care was largely supportive of eventual need for kidney/liver transplantation in PH1 and PH2. Together with the Oxalosis and Hyperoxaluria Foundation, the authors developed a diagnostic algorithm for PH1 and in this report outline best clinical practices related to its early diagnosis, supportive treatment, and long-term management, including the use of the novel RNAi. PH1-focused approaches to dialysis and kidney/liver transplantation for PH patients with progression to chronic kidney disease/kidney failure and systemic oxalosis are suggested. Therapeutic advances for this devastating disease heighten the importance of early diagnosis and informed treatment.

Clinical characteristics and favorable treatment responses of recurrent focal segmental glomerulosclerosis or steroid-resistant nephrotic syndrome in children after kidney transplantation.

BACKGROUND: Recurrence of focal segmental glomerulosclerosis (FSGS) or steroid-resistant nephrotic syndrome (SRNS) after kidney transplant leads to significant morbidity and potentially earlier allograft loss. To date however, reported rates, risk factors and treatment outcomes have varied widely. METHODS: We applied computational phenotypes to a multicenter aggregation of electronic health records data from 7 large pediatric health systems in the USA, to identify recurrence rates, risk factors, and treatment outcomes. We refined the data collection by chart review. RESULTS: From > 7 million patients, we compared children with primary FSGS/SRNS who received a kidney transplant between 2009 and 2020 and who either developed recurrence (n = 67/165; 40.6%) or did not (n = 98/165). Serum albumin level at time of transplant was significantly lower and recipient HLA DR7 presence was significantly higher in the recurrence group. By 36 months post-transplant, complete remission occurred in 58.2% and partial remission in 17.9%. Through 6 years post-transplant, no remission after recurrence was associated with an increased risk of allograft loss over time (p < 0.0001), but any remission showed similar allograft survival and function decline to those with no recurrence. Since treatments were used in non-random fashion, using spline curves and multivariable non-linear analyses, complete + partial remission chance was significantly higher with greater plasmapheresis sessions, CTLA4-Ig doses or LDL-apheresis sessions. Only treatment with anti-CD20, CTLA4-Ig agents, or LDL-apheresis sessions were associated with complete remission. Excluding 25 patients with mutations did not significantly change our results. CONCLUSIONS: Our contemporary high-risk cohort had higher favorable response rates than most prior reports, from combinations of agents.

Reverse phenotyping facilitates disease allele calling in exome sequencing of patients with CAKUT.

PURPOSE: Congenital anomalies of the kidneys and urinary tract (CAKUT) constitute the leading cause of chronic kidney disease in children. In total, 174 monogenic causes of isolated or syndromic CAKUT are known. However, syndromic features may be overlooked when the initial clinical diagnosis of CAKUT is made. We hypothesized that the yield of a molecular genetic diagnosis by exome sequencing (ES) can be increased by applying reverse phenotyping, by re-examining the case for signs/symptoms of the suspected clinical syndrome that results from the genetic variant detected by ES. METHODS: We conducted ES in an international cohort of 731 unrelated families with CAKUT. We evaluated ES data for variants in 174 genes, in which variants are known to cause isolated or syndromic CAKUT. In cases in which ES suggested a previously unreported syndromic phenotype, we conducted reverse phenotyping. RESULTS: In 83 of 731 (11.4%) families, we detected a likely CAKUT-causing genetic variant consistent with an isolated or syndromic CAKUT phenotype. In 19 of these 83 families (22.9%), reverse phenotyping yielded syndromic clinical findings, thereby strengthening the genotype-phenotype correlation. CONCLUSION: We conclude that employing reverse phenotyping in the evaluation of syndromic CAKUT genes by ES provides an important tool to facilitate molecular genetic diagnostics in CAKUT.

Treatment of post-transplant recurrent FSGS in children using plasmapheresis and augmentation of immunosuppression.

BACKGROUND: Up to 60% of pediatric renal transplant recipients with end-stage renal disease due to primary focal and segmental glomerulosclerosis (FSGS) may develop recurrent disease. Such recurrence is associated with poor prognosis if no remission is achieved. We report a single center experience with a protocol based on plasmapheresis and increased immunosuppression that resulted in a high long-lived remission rate. METHODS: This retrospective cohort study included consecutive pediatric renal transplant patients with recurrent FSGS treated with a standardized protocol using plasmapheresis and cyclophosphamide to supplement usual post-transplant immunosuppression with calcineurin inhibitors and steroids. Relapse was defined as urinary protein/creatinine ratio > 1.0 g/g and remission as < 0.5 g/g. RESULTS: Seventeen patients with FSGS recurrence post-transplant were treated. All had therapy resistant FSGS in native kidneys and had been on dialysis from 4 to 10 years. Of the 17, one died perioperatively from a pulmonary thromboembolism. Fifteen others achieved a complete remission within 3 months of treatment for FSGS recurrence. After a median follow-up period of 4 years, there were no recurrences of significant proteinuria. One patient achieved remission with rituximab. CONCLUSION: The addition of plasmapheresis and cyclophosphamide to a calcineurin- and steroid-based immunosuppression regime was highly successful in inducing high remission rates with recurrent FSGS. Prospective trials are needed to evaluate further the efficacy of increased immunosuppression along with plasmapheresis in this setting.

Continued reduction in peritonitis rates in pediatric dialysis centers: results of the Standardizing Care to Improve Outcomes in Pediatric End Stage Renal Disease (SCOPE) Collaborative.

BACKGROUND: In its first 3 years, the Standardizing Care to Improve Outcomes in Pediatric End Stage Renal Disease (SCOPE) Collaborative demonstrated a statistically significant increase in the likelihood of compliance with a standardized follow-up care bundle and a significant reduction in peritonitis. We sought to determine if compliance with care bundles and low peritonitis rates could be sustained in centers continuously participating for 84 months. METHODS: Centers that participated from collaborative launch through the 84-month study period and provided pre-launch peritonitis rates were included. Children on maintenance peritoneal dialysis were eligible for enrollment. Changes in bundle compliance were assessed using a logistic regression model or a generalized linear mixed model (GLMM). Changes in average annualized peritonitis rates over time were modeled using GLMMs. RESULTS: Nineteen centers contributed 1055 patients with 1268 catheters and 17,247 follow-up encounters. The likelihood of follow-up compliance increased significantly over the study period (OR 1.05 95% confidence interval (CI) 1.03, 1.07; p < 0.001). Centers achieved ≥ 80% follow-up bundle compliance by 28 months and maintained a mean compliance of 84% between 28 and 84 months post-launch. Average monthly peritonitis rates decreased from 0.53 (95% CI 0.37, 0.70) infections per patient-year pre-launch to 0.30 (95% CI 0.23, 0.43) at 84 months post-launch, p < 0.001. CONCLUSIONS: Centers participating in the SCOPE Collaborative for 84 months achieved and maintained a high level of compliance with a standardized follow-up care bundle and demonstrated a significant and continued reduction in average monthly peritonitis rates.

A prospective multi-center quality improvement initiative (NINJA) indicates a reduction in nephrotoxic acute kidney injury in hospitalized children.

Nephrotoxic medication (NTMx) exposure is a common cause of acute kidney injury (AKI) in hospitalized children. The Nephrotoxic Injury Negated by Just-in time Action (NINJA) program decreased NTMx associated AKI (NTMx-AKI) by 62% at one center. To further test the program, we incorporated NINJA across nine centers with the goal of reducing NTMx exposure and, consequently, AKI rates across these centers. NINJA screens all non-critically ill hospitalized patients for high NTMx exposure (over three medications on the same day or an intravenous aminoglycoside over three consecutive days), and then recommends obtaining a daily serum creatinine level in exposed patients for the duration of, and two days after, exposure ending. Additionally, substitution of equally efficacious but less nephrotoxic medications for exposed patients starting the day of exposure was recommended when possible. The main outcome was AKI as defined by the Kidney Disease Improving Global Outcomes (KDIGO) serum creatinine criteria (increase of 50% or 0.3 mg/dl over baseline). The primary outcome measure was AKI episodes per 1000 patient-days. Improvement was defined by statistical process control methodology and confirmed by Autoregressive Integrated Moving Average (ARIMA) modeling. Eight consecutive bi-weekly measure rates in the same direction from the established baseline qualified as special cause change for special process control. We observed a significant and sustained 23.8% decrease in NTMx-AKI rates by statistical process control analysis and by ARIMA modeling; similar to those of the pilot single center. Thus, we have successfully applied the NINJA program to multiple pediatric institutions yielding decreased AKI rates.

Early outcomes comparing induction with antithymocyte globulin vs alemtuzumab in two steroid-avoidance protocols in pediatric renal transplantation.

Steroid avoidance in pediatric kidney transplants was found effective with extended daclizumab induction. Upon discontinuation of daclizumab, lymphocyte-depleting agents became used, with little comparative data. We assessed outcomes in children undergoing low immunologic-risk deceased donor (DD) kidney transplants using induction with antithymocyte globulin (ATG) compared to alemtuzumab. We reviewed consecutive DD kidney transplants from January 2015 to September 2017 at two pediatric centers that used different lymphocyte-depleting agents in steroid-avoidance protocols: ATG (Center A) and alemtuzumab (Center B), with tacrolimus and MMF as maintenance immunosuppression. Anti-infective prophylaxis was based on center protocol. Over the first year post-tx, there were similar rates of infections. EBV and BK viremia were comparable though Center A manifested more low-grade CMV viremia (A 46% vs B 0%; P = .0009) at median onset 1.8 months, followed by early seroconversion. Reduction of immunosuppression did not differ between groups. DSA at 1 year was similar (A 8% vs 13%) with low rates of BPAR. Need for steroid-based conversion was low. There were no graft losses and no differences in median eGFR at 30, 90, 180, and 365 days. (a) 1-year graft outcomes are excellent in steroid-avoidance regimens using ATG or alemtuzumab induction; (b) conversion to steroid-based therapy is low; (c) alemtuzumab/high-dose MMF is associated with lower WBC and more GCSF use; (d) alemtuzumab/higher dose MMF results in more diarrhea and azathioprine conversion than ATG/lower dose MMF; (e) CMV viremia is seen more often with ATG use with infection prophylaxis reduction; however, seroconversion occurs promptly.

Effects of changes in adult erythropoietin dosing guidelines on erythropoietin dosing practices, anemia, and blood transfusion in children on hemodialysis: findings from North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS).

BACKGROUND: While adult hemodialysis (HD) patients have increased morbidity with higher target hemoglobin levels, similar findings have not been demonstrated in pediatric patients. We evaluated changes in transfusions, anemia frequency, and erythropoietin (epo) dosing among pediatric HD patients before, during, and after implementation of federal dialysis payment policies regarding epo dosing for adult HD patients. METHODS: This is a retrospective cohort study of pediatric HD patients enrolled in NAPRTCS. We evaluated need for transfusion, anemia, median hemoglobin, and median epo dose 6 months after starting HD in 3 eras: baseline (2003-2007), implementation (2008-2011), and post implementation (2012-2016). We used multivariate logistic regression models to evaluate potential differences in transfusion across the eras. RESULTS: Six months after dialysis initiation, 12.6% of patients required transfusion pre-implementation, 17.9% during implementation, and 15.5% post implementation. Anemia occurred in 17.4% of patients pre, 23.5% during, and 23.8% post implementation, with median hemoglobin levels of 11.9 g/dL pre, 11 g/dL during, and 11 g/dL post implementation. Epo use was high across all 3 eras, but epo dosing decreased during and post implementation, despite more anemia during these periods. Odds of transfusion in implementation era compared with pre-implementation was 1.75 (95% CI 1.11-2.77) and odds of transfusion in post implementation era compared with pre was 1.19 (95% CI 0.71-1.98), controlling for age, race, gender, and prior transplant status. CONCLUSIONS: During and following implementation of adult epo dosing guidelines, transfusion and anemia frequency increased in pediatric HD patients. Ideal target hemoglobin levels for pediatric dialysis patients warrant further study.

Using Electronic Health Record Data to Rapidly Identify Children with Glomerular Disease for Clinical Research.

BACKGROUND: The rarity of pediatric glomerular disease makes it difficult to identify sufficient numbers of participants for clinical trials. This leaves limited data to guide improvements in care for these patients. METHODS: The authors developed and tested an electronic health record (EHR) algorithm to identify children with glomerular disease. We used EHR data from 231 patients with glomerular disorders at a single center to develop a computerized algorithm comprising diagnosis, kidney biopsy, and transplant procedure codes. The algorithm was tested using PEDSnet, a national network of eight children's hospitals with data on >6.5 million children. Patients with three or more nephrologist encounters (n=55,560) not meeting the computable phenotype definition of glomerular disease were defined as nonglomerular cases. A reviewer blinded to case status used a standardized form to review random samples of cases (n=800) and nonglomerular cases (n=798). RESULTS: The final algorithm consisted of two or more diagnosis codes from a qualifying list or one diagnosis code and a pretransplant biopsy. Performance characteristics among the population with three or more nephrology encounters were sensitivity, 96% (95% CI, 94% to 97%); specificity, 93% (95% CI, 91% to 94%); positive predictive value (PPV), 89% (95% CI, 86% to 91%); negative predictive value, 97% (95% CI, 96% to 98%); and area under the receiver operating characteristics curve, 94% (95% CI, 93% to 95%). Requiring that the sum of nephrotic syndrome diagnosis codes exceed that of glomerulonephritis codes identified children with nephrotic syndrome or biopsy-based minimal change nephropathy, FSGS, or membranous nephropathy, with 94% sensitivity and 92% PPV. The algorithm identified 6657 children with glomerular disease across PEDSnet, ≥50% of whom were seen within 18 months. CONCLUSIONS: The authors developed an EHR-based algorithm and demonstrated that it had excellent classification accuracy across PEDSnet. This tool may enable faster identification of cohorts of pediatric patients with glomerular disease for observational or prospective studies.

Whole-Exome Sequencing Enables a Precision Medicine Approach for Kidney Transplant Recipients.

BACKGROUND: Whole-exome sequencing (WES) finds a CKD-related mutation in approximately 20% of patients presenting with CKD before 25 years of age. Although provision of a molecular diagnosis could have important implications for clinical management, evidence is lacking on the diagnostic yield and clinical utility of WES for pediatric renal transplant recipients. METHODS: To determine the diagnostic yield of WES in pediatric kidney transplant recipients, we recruited 104 patients who had received a transplant at Boston Children's Hospital from 2007 through 2017, performed WES, and analyzed results for likely deleterious variants in approximately 400 genes known to cause CKD. RESULTS: By WES, we identified a genetic cause of CKD in 34 out of 104 (32.7%) transplant recipients. The likelihood of detecting a molecular genetic diagnosis was highest for patients with urinary stone disease (three out of three individuals), followed by renal cystic ciliopathies (seven out of nine individuals), steroid-resistant nephrotic syndrome (nine out of 21 individuals), congenital anomalies of the kidney and urinary tract (ten out of 55 individuals), and chronic glomerulonephritis (one out of seven individuals). WES also yielded a molecular diagnosis for four out of nine individuals with ESRD of unknown etiology. The WES-related molecular genetic diagnosis had implications for clinical care for five patients. CONCLUSIONS: Nearly one third of pediatric renal transplant recipients had a genetic cause of their kidney disease identified by WES. Knowledge of this genetic information can help guide management of both transplant patients and potential living related donors.

Renal replacement therapy in the management of intoxications in children: recommendations from the Pediatric Continuous Renal Replacement Therapy (PCRRT) workgroup.

BACKGROUND: Intentional or unintentional ingestions among children and adolescents are common. There are a number of ingestions amenable to renal replacement therapy (RRT). METHODS: We systematically searched PubMed/Medline, Embase, and Cochrane databases for literature regarding drugs/intoxicants and treatment with RRT in pediatric populations. Two experts from the PCRRT (Pediatric Continuous Renal Replacement Therapy) workgroup assessed titles, abstracts, and full-text articles for extraction of data. The data from the literature search was shared with the PCRRT workgroup and two expert toxicologists, and expert panel recommendations were developed. RESULTS AND CONCLUSIONS: We have presented the recommendations concerning the use of RRTs for treatment of intoxications with toxic alcohols, lithium, vancomycin, theophylline, barbiturates, metformin, carbamazepine, methotrexate, phenytoin, acetaminophen, salicylates, valproic acid, and aminoglycosides.

Whole-Exome Sequencing Identifies Causative Mutations in Families with Congenital Anomalies of the Kidney and Urinary Tract.

BACKGROUND: Congenital anomalies of the kidney and urinary tract (CAKUT) are the most prevalent cause of kidney disease in the first three decades of life. Previous gene panel studies showed monogenic causation in up to 12% of patients with CAKUT. METHODS: We applied whole-exome sequencing to analyze the genotypes of individuals from 232 families with CAKUT, evaluating for mutations in single genes known to cause human CAKUT and genes known to cause CAKUT in mice. In consanguineous or multiplex families, we additionally performed a search for novel monogenic causes of CAKUT. RESULTS: In 29 families (13%), we detected a causative mutation in a known gene for isolated or syndromic CAKUT that sufficiently explained the patient's CAKUT phenotype. In three families (1%), we detected a mutation in a gene reported to cause a phenocopy of CAKUT. In 15 of 155 families with isolated CAKUT, we detected deleterious mutations in syndromic CAKUT genes. Our additional search for novel monogenic causes of CAKUT in consanguineous and multiplex families revealed a potential single, novel monogenic CAKUT gene in 19 of 232 families (8%). CONCLUSIONS: We identified monogenic mutations in a known human CAKUT gene or CAKUT phenocopy gene as the cause of disease in 14% of the CAKUT families in this study. Whole-exome sequencing provides an etiologic diagnosis in a high fraction of patients with CAKUT and will provide a new basis for the mechanistic understanding of CAKUT.

Whole exome sequencing frequently detects a monogenic cause in early onset nephrolithiasis and nephrocalcinosis.

The incidence of nephrolithiasis continues to rise. Previously, we showed that a monogenic cause could be detected in 11.4% of individuals with adult-onset nephrolithiasis or nephrocalcinosis and in 16.7-20.8% of individuals with onset before 18 years of age, using gene panel sequencing of 30 genes known to cause nephrolithiasis/nephrocalcinosis. To overcome the limitations of panel sequencing, we utilized whole exome sequencing in 51 families, who presented before age 25 years with at least one renal stone or with a renal ultrasound finding of nephrocalcinosis to identify the underlying molecular genetic cause of disease. In 15 of 51 families, we detected a monogenic causative mutation by whole exome sequencing. A mutation in seven recessive genes (AGXT, ATP6V1B1, CLDN16, CLDN19, GRHPR, SLC3A1, SLC12A1), in one dominant gene (SLC9A3R1), and in one gene (SLC34A1) with both recessive and dominant inheritance was detected. Seven of the 19 different mutations were not previously described as disease-causing. In one family, a causative mutation in one of 117 genes that may represent phenocopies of nephrolithiasis-causing genes was detected. In nine of 15 families, the genetic diagnosis may have specific implications for stone management and prevention. Several factors that correlated with the higher detection rate in our cohort were younger age at onset of nephrolithiasis/nephrocalcinosis, presence of multiple affected members in a family, and presence of consanguinity. Thus, we established whole exome sequencing as an efficient approach toward a molecular genetic diagnosis in individuals with nephrolithiasis/nephrocalcinosis who manifest before age 25 years.

Exit site and tunnel infections in children on chronic peritoneal dialysis: findings from the Standardizing Care to Improve Outcomes in Pediatric End Stage Renal Disease (SCOPE) Collaborative.

BACKGROUND: The Standardizing Care to Improve Outcomes in Pediatric End Stage Renal Disease (SCOPE) Collaborative is a quality improvement initiative to reduce dialysis-associated infections. The frequency of peritoneal dialysis (PD) catheter exit site infection (ESI) and variables influencing its development and end result are unclear. We sought to determine ESI rates, to elucidate the epidemiology, risk factors, and outcomes for ESI, and to assess for association between provider compliance with care bundles and ESI risk. METHODS: We reviewed demographic, dialysis and ESI data, and care bundle adherence and outcomes for SCOPE enrollees from October 2011 to September 2014. ESI involved only the exit site, only the subcutaneous catheter tunnel, or both. RESULTS: A total of 857 catheter insertions occurred in 734 children over 10,110 cumulative months of PD provided to these children. During this period 207 ESIs arose in 124 children or 0.25 ESIs per dialysis year. Median time to ESI was 392 days, with 69% of ESIs involving exit site only, 23% involving the tunnel only, and 8% involving both sites. Peritonitis developed in 6%. ESI incidence was associated with age (p = 0.003), being the lowest in children aged < 2 years and highest in those aged 6-12 years, and with no documented review of site care or an exit site score of > 0 at prior month's visit (p < 0.001). Gender, race, end stage renal disease etiology, exit site orientation, catheter cuff number or mobilization, and presence of G-tube, stoma, or vesicostomy were unassociated with ESI incidence. Of the ESIs reported, 71% resolved with treatment, 24% required hospitalization, and 9% required catheter removal, generally secondary to tunnel infection. CONCLUSIONS: Exit site infections occur at an annualized rate of 0.25, typically well into the dialysis course. Younger patient age and documented review of site care are associated with lower ESI rates. Although most ESIs resolve, hospitalization is frequent, and tunnel involvement/catheter loss complicate outcomes.

Analysis of 24 genes reveals a monogenic cause in 11.1% of cases with steroid-resistant nephrotic syndrome at a single center.

BACKGROUND: Steroid-resistant nephrotic syndrome (SRNS) is the second most frequent cause of end-stage renal disease (ESRD) among patients manifesting at under 25 years of age. We performed mutation analysis using a high-throughput PCR-based microfluidic technology in 24 single-gene causes of SRNS in a cohort of 72 families, who presented with SRNS before the age of 25 years. METHODS: Within an 18-month interval, we obtained DNA samples, pedigree information, and clinical information from 77 consecutive children with SRNS from 72 different families seen at Boston Children's Hospital (BCH). Mutation analysis was completed by combining high-throughput multiplex PCR with next-generation sequencing. We analyzed the sequences of 18 recessive and 6 dominant genes of SRNS in all 72 families for disease-causing variants. RESULTS: We identified the disease-causing mutation in 8 out of 72 (11.1%) families. Mutations were detected in the six genes: NPHS1 (2 out of 72), WT1 (2 out of 72), NPHS2, MYO1E, TRPC6, and INF2. Median age at onset was 4.1 years in patients without a mutation (range 0.5-18.8), and 3.2 years in those in whom the causative mutation was detected (range 0.1-14.3). Mutations in dominant genes presented with a median onset of 4.5 years (range 3.2-14.3). Mutations in recessive genes presented with a median onset of 0.5 years (range 0.1-3.2). CONCLUSION: Our molecular genetic diagnostic study identified underlying monogenic causes of steroid-resistant nephrotic syndrome in ~11% of patients with SRNS using a cost-effective technique. We delineated some of the therapeutic, diagnostic, and prognostic implications. Our study confirms that genetic testing is indicated in pediatric patients with SRNS.

Dialysis in Children and Adolescents: The Pediatric Nephrology Perspective.

The care of children with end-stage renal disease (ESRD) is highly specialized and often poorly understood by nonpediatric providers and facility/institution administrators. As such, this position paper has been created to offer provider, facility, and institutional guidance regarding the components of care necessary for children receiving dialysis. Key differences between adult and pediatric dialysis units are highlighted. Responsibilities and expectations of the members of the interdisciplinary dialysis team are outlined as they pertain specifically to the care of pediatric dialysis patients. Physical and staffing requirements of the dialysis facility are reviewed, again focusing on unique needs and challenges faced by the pediatric dialysis care team. Among these, vascular access options and proper planning of ESRD care are underscored. Pediatric quality-of-life metrics differ significantly from adult quality variables, and proper tools for assessment must be used. Endorsed by the Council of the American Society of Pediatric Nephrology (ASPN), this position paper serves as a reference tool for the provision of care to pediatric patients with ESRD.

Clinical outcomes and survival in pediatric patients initiating chronic dialysis: a report of the NAPRTCS registry.

BACKGROUND: The 2011 annual report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) registry comprises data on 6482 dialysis patients over the past 20 years of the registry. METHODS: The study compared clinical parameters and patient survival in the first 10 years of the registry (1992-2001) with the last decade of the registry (2002-2011). RESULTS: There was a significant increase in hemodialysis as the initiating dialysis modality in the most recent cohort (42% vs. 36%, p < 0.001). Patients in the later cohort were less likely to have a hemoglobin <10 g/dl [odds ratio (OR) 0.68; confidence interval (CI) 0.58-0.81; p < 0.001] and height z-score <2 standard deviations (SD) below average (OR 0.68, CI 0.59-0.78, p < 0.0001). They were also more likely to have a parathyroid hormone (PTH) level two times above the upper limits of normal (OR 1.39, CI 1.21-1.60, p < 0.0001). Although hypertension was common regardless of era, patients in the 2002-2011 group were less likely to have blood pressure >90th percentile (OR 1.39, CI 1.21-1.60, p < 0.0001), and a significant improvement in survival at 36 months after dialysis initiation was observed in the 2002-2011 cohort compared with the 1992-2001 cohort (95% vs. 90%, respectively). Cardiopulmonary causes were the most common cause of death in both cohorts. Young age, growth deficit, and black race were poor predictors of survival. CONCLUSIONS: The survival of pediatric patients on chronic dialysis has improved over two decades of dialysis registry data, specifically for children <1year.

Arteriovenous access monitoring with ultrasound dilution in a pediatric hemodialysis unit.

BACKGROUND: Permanent arteriovenous (AV) access is the preferred access for dialysis delivery in children and adolescents requiring chronic hemodialysis (HD). Ultrasound dilution (UD) monitoring of AV access flow is widely used in adult HD units for the early detection of stenosis but experience in pediatrics is limited. METHODS: We monitored all maintenance HD patients with AV access using a noninvasive screening algorithm based on UD access flow. We assessed the effectiveness of this algorithm by comparing it to fistulagrams and its impact on AV access-related morbidity. RESULTS: AV access thrombosis rates fell from 13.5 per 100 patient-months on HD during the baseline period to 3.5 per 100 patient-months on HD during the screening period (p < 0.04). The mean blood flow rate by UD measurement was lower in AV accesses that went on to thrombose compared to those without thrombosis (1,203 ml/min/1.73 m(2) vs. 1,683 ml/min/1.73 m(2), p < 0.001). When compared to fistulagrams, the screening algorithm was 94% sensitive and 77% specific in detecting hemodynamically significant stenosis, with positive and negative predictive values of 83 and 91% respectively. CONCLUSIONS: A noninvasive UD screening algorithm of AV access flow is very sensitive in detecting hemodynamically significant stenosis and can decrease AV access thrombosis rates.