North American Pediatric Renal Trials And Collaborative Studies Research Articles

Clinical Outcomes in Children on Maintenance Dialysis: A Report of the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) Registry

Clinical Outcomes in Children on Maintenance Dialysis: A Report of the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) Registry

Racial Differences in Outcomes in Children on Maintenance Dialysis Enrolled in the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS)

Racial Differences in Outcomes in Children on Maintenance Dialysis Enrolled in the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS)

Identification of Patients with Potential Undiagnosed Atypical Hemolytic Uremic Syndrome (aHUS) in the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) Registry

Identification of Patients with Potential Undiagnosed Atypical Hemolytic Uremic Syndrome (aHUS) in the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) Registry

Outcomes based on induction regimens in pediatric kidney transplantation: a NAPRTCS and PHIS collaborative study.

Induction agent used at the time of kidney transplant is often based upon center practice and recipient characteristics. We evaluated outcomes across induction therapies among children enrolled in the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) transplant registry with data in the Pediatric Health Information System (PHIS). This is a retrospective study of merged data from NAPRTCS and PHIS. Participants were grouped by induction agent: interleukin-2 receptor blocker (IL-2 RB), anti-thymocyte/anti-lymphocyte globulin (ATG/ALG), and alemtuzumab. Outcomes assessed included 1-, 3-, and 5-year allograft function and survival, rejection, viral infections, malignancy, and death. A total of 830 children transplanted between 2010 and 2019. At 1year post-transplant, the alemtuzumab group had higher median eGFR (86ml/min/1.73m2) compared to IL-2 RB and ATG/ALG (79 and 75ml/min/1.73m2, respectively; P < 0.001); at 3 and 5years, there was no difference. Adjusted eGFR over time was similar across all induction agents. Rejection rates were lower among the alemtuzumab group vs. IL-2RBand ATG (13.9% vs. 27.3% and 24.6%, respectively; P = 0.006). Adjusted ATG/ALG and alemtuzumab had higher hazard ratio for time to graft failure compared to IL-2 RB (HR 2.48 and HR 2.11, respectively; P < 0.05). Incidence of malignancy, mortality, and time to first viral infection was similar. Although rejection and allograft loss rates were distinct, the incidences of viral infection and malignancy were comparable across induction agents. By 3years post-transplant, there was no difference in eGFR. A higher resolution version of the Graphical abstract is available as Supplementary information.

Practice patterns and outcomes of maintenance dialysis in children < 2years of age: a report of the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS).

Peritoneal dialysis (PD) is the preferred mode of kidney replacement therapy (KRT) in infants and young children with kidney failure. Hemodialysis (HD) is used less often due to the technical challenges and risk of complications in smaller patients. There are limited data on chronic HD in this patient population. This was a retrospective study of children younger than 24months on HD and PD in the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) registry between January 1992 and December 2018. We compared demographic, clinical, and laboratory data and outcomes, including patient survival and kidney transplantation. We identified 1125 infants and toddlers younger than 2years of age who initiated KRT from January 1992 to December 2018. Of those, 1011 (89.8%) initiated peritoneal dialysis and 114 (10.2%) initiated hemodialysis. Median (IQR) age at HD onset was 12 (5.6-18.7) months compared to 4.6 (0.8-11.7) months at PD onset (p < 0.001). The primary cause of kidney failure with replacement therapy was congenital anomalies of the kidney and urinary tract (56.2% of PD versus 39.5% of HD group). Patients on HD had superior growth and nutrition markers than those on PD. Patient survival was similar between the two groups. While HD may not be the modality of choice for chronic KRT in younger children, 10% of children younger than 24months of age receive maintenance HD and the numbers have increased over time. Patient survival on dialysis is similar irrespective of dialysis modality. A higher resolution version of the Graphical abstract is available as Supplementary information.

Dialysis Outcomes for Children With Lupus Nephritis Compared to Children With Other Forms of Nephritis: A Retrospective Cohort Study

Children with lupus nephritis (LN) are at high risk of developing kidney failure requiring initiation of kidney replacement therapy. This study compared outcomes among children with LN on dialysis with children with non-lupus glomerular disease and investigated risk factors for adverse outcomes among children with LN on dialysis. Retrospective cohort study. Children and adolescents aged 6-20 years with LN (n= 231) and non-lupus glomerular disease (n= 1,726) who initiated maintenance dialysis 1991-2018 and were enrolled in the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) registry. Lupus nephritis. Hospitalization, mortality, and time to transplant. Contingency tables were used to compare hospitalizations, and multivariable cause-specific hazards models were used to compare rates of death and transplantation in children with LN compared with those with non-lupus glomerular disease. Using data from children with LN, multivariable logistic regression models were fit to evaluate the risk factors for hospitalization, and multivariable Cox regression models were fit to evaluate factors associated with kidney transplantation. Children with LN were more likely to be hospitalized in the first year after dialysis initiation (63.3% vs 48.6%, P< 0.001) and were less likely to receive a kidney transplant in the first 3 years after dialysis initiation (year 0-1: adjusted hazard ratio [AHR], 0.36 [95% CI, 0.23-0.57], P< 0.001; year 1-3: AHR, 0.73 [95% CI, 0.54-0.98], P= 0.04). Anemia was associated with hospitalization after dialysis initiation (adjusted OR, 4.44 [95% CI, 1.44-13.66], P= 0.01). Non-White race was associated with a lower rate of kidney transplantation (AHR, 0.47 [95% CI, 0.27-0.82], P= 0.01). LN was not associated with death while on dialysis (AHR, 1.21 [95% CI, 0.47-3.11], P= 0.7). The NAPRTCS registry does not collect information on lupus disease activity or medication doses and has limited data on medication use. Children and adolescents with LN on dialysis are at higher risk for adverse outcomes including hospitalization and lower rates of kidney transplantation compared with children with non-lupus glomerular disease receiving maintenance dialysis.

Reassessing Rabbit Antithymocyte Globulin Induction in Kidney Transplantation (RETHINK): An Analysis of the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) Registry.

There is no consensus on rabbit antithymocyte globulin (rATG) dose used for induction immunosuppression in pediatric kidney transplants. We aimed to identify whether a lower rATG dose provides safe and effective immunosuppression compared with a higher dose. We retrospectively analyzed all first-time kidney transplant recipients (aged <21 y) in the North American Pediatric Renal Trials and Collaborative Studies registry since 1998 on mycophenolate mofetil- and tacrolimus-based immunosuppression with rATG induction. An a priori cutoff of 7.5 mg/kg cumulative rATG dose was used to identify low (<7.5 mg/kg) and high (≥7.5 mg/kg) exposure groups. Primary outcome was time to first-acute rejection episode. Secondary outcomes included graft function, patient survival, hospitalizations due to infections, and time to first-posttransplant lymphoproliferative disorder episode. Four hundred fifty-five patients met inclusion criteria (59% male, 49% whites, 26% blacks, 38% living donor source). Median cumulative rATG dose was 6.8 mg/kg with a median of 5 doses and a median 1.5 mg/kg/dose introduced at a median of postoperative 0 days. Sixty-four percent received <7.5 mg/kg total rATG. There was no difference in age at transplant, gender, race, end-stage renal disease causes, or HLA mismatch among groups. Time to first-acute rejection was similar (P = 0.07). There was no significant difference in graft or patient survival or time to posttransplant lymphoproliferative disorder. Hospitalization for infection rates was similar. These data demonstrate a wide variation in cumulative rATG induction dose. A smaller rATG dose <7.5 mg/kg may provide effective and safe immunosuppression compared with a higher dose.

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).

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. 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. 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. 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.

Whole-exome resequencing reveals recessive mutations in TRAP1 in individuals with CAKUT and VACTERL association

Congenital abnormalities of the kidney and urinary tract (CAKUT) account for approximately half of children with chronic kidney disease and they are the most frequent cause of end-stage renal disease in children in the US. However, its genetic etiology remains mostly elusive. VACTERL association is a rare disorder that involves congenital abnormalities in multiple organs including the kidney and urinary tract in up to 60% of the cases. By homozygosity mapping and whole exome resequencing combined with high-throughput mutation analysis by array-based multiplex PCR and next-generation sequencing, we identified recessive mutations in the gene TNF receptor-associated protein 1 (TRAP1) in two families with isolated CAKUT and three families with VACTERL association. TRAP1 is a heat shock protein 90-related mitochondrial chaperone possibly involved in antiapoptotic and endoplasmic reticulum-stress signaling. Trap1 is expressed in renal epithelia of developing mouse kidney E13.5 and in the kidney of adult rats, most prominently in proximal tubules and in thick medullary ascending limbs of Henle’s loop. Thus, we identified mutations in TRAP1 as highly likely causing CAKUT or CAKUT in VACTERL association.

Posterior Urethral Valve Treatments and Outcomes in Children Receiving Kidney Transplants

We evaluated the impact of surgical approaches to posterior urethral valves on renal transplant survival and compared transplant survival in children with vs without posterior urethral valves. We reviewed the records of all children who underwent renal transplantation from January 1984 to March 2008 and performed univariate subgroup analysis in those with posterior urethral valves. We evaluated the ureteroneocystotomy method, immunosuppression and valve treatment. In patients with posterior urethral valves we regarded nocturnal and/or daytime incontinence, severe urgency and the need for intermittent catheterization or double voiding for increased post-void residual urine as signs of bladder dysfunction. The initial renal transplant was received by 418 children at a mean age of 5.6 years. The 59 boys with posterior urethral valves received a total of 69 kidneys. By 8-year followup the kidney had failed in 24 of 59 boys with and 143 of 359 without posterior urethral valves (OR 0.9665, 95% CI 0.5462-1.692, p = 0.9105). Immunosuppression was consistent in the 2 groups. Outcomes were similar across all ureteroneocystotomy techniques. Initial management for posterior urethral valves was valve ablation alone in 12 boys, vesicostomy in 7 and supravesical diversion in 11. There was no difference in transplant survival or bladder dysfunction based on valve intervention. In 18 boys (55%) we noted overlapping signs of bladder dysfunction, of whom 11 performed intermittent catheterization or had increased post-void residual urine, 4 had severe urgency, 4 had daytime incontinence and 7 had nocturnal incontinence. Bladder dysfunction did not predict increased graft loss (OR 3.306, 95% CI 0.7615-16.27, p = 0.1134). Of children who undergo renal transplantation boys with posterior urethral valves do not have a higher graft failure rate. Treatment for posterior urethral valves did not significantly impact transplant survival or bladder dysfunction.

Calcineurin Inhibitor-Free Immunosuppression in Pediatric Renal Transplantation

The introduction, in the mid-1980s, of calcineurin inhibitors - namely ciclosporin (cyclosporine) and later tacrolimus - has significantly improved short-term renal graft survival by lowering acute rejection rates in both adult and pediatric kidney transplantation. Nonetheless, long-term transplant survival is still not satisfactory, with calcineurin inhibitor-induced chronic nephrotoxicity being one of the main causes of progressive nephron loss and declining renal transplant function. Hence, different immunosuppressant regimens have been proposed to avoid or ameliorate calcineurin inhibitor-induced nephrotoxicity. These comprise the use of non-depleting or depleting antibodies for calcineurin inhibitor minimization, calcineurin inhibitor avoidance, or calcineurin inhibitor withdrawal from mycophenolate mofetil-based immunosuppressant protocols. De novo use of a mammalian target of rapamycin (mTOR) inhibitor (sirolimus or everolimus) or conversion from a calcineurin inhibitor to an mTOR inhibitor may constitute another therapeutic option to avoid or reduce calcineurin inhibitor-induced nephrotoxicity. To date, complete calcineurin inhibitor avoidance seems to be inappropriate because other relatively potent immunosuppressant agents such as lymphocyte-depleting antibodies are needed for rejection prophylaxis, which are frequently accompanied by a higher incidence of infections and an unacceptably high acute rejection rate under calcineurin inhibitor avoidance. In some studies, calcineurin inhibitor withdrawal in adult and pediatric kidney allograft recipients with stable or declining transplant function has been associated with an amelioration of renal function; however, this is attained at the cost of a higher acute rejection rate in 10-20% of patients. It has been frequently stressed that conversion from a calcineurin inhibitor-based regimen to an mTOR inhibitor-based immunosuppressant regimen should be performed early (e.g. 3 or 6 months post-transplant) in patients with well-preserved renal transplant function without significant proteinuria in order to prevent, or at least limit, calcineurin inhibitor-induced tissue damage and provide long-term benefit. It should be borne in mind though that the use of an mTOR inhibitor carries the risk of potential adverse events such as aggravation of proteinuria, hyperlipidemia, myelosuppression, and hypergonadotropic hypogonadism. Even though everolimus may be better tolerated than sirolimus, studies on everolimus for calcineurin inhibitor-free immunosuppression in the pediatric kidney transplant patient population are lacking. At present, the safest therapeutic strategy for pediatric renal allograft recipients with chronic calcineurin inhibitor-induced nephrotoxicity appears to be a mycophenolate mofetil-based regimen with low-dose calcineurin inhibitor therapy and corticosteroids; available published data show that dual immunosuppression with mycophenolate mofetil and corticosteroids, as well as an mTOR inhibitor plus mycophenolate mofetil plus corticosteroid-based regimens, are associated with an increased risk of acute rejection episodes. In individual patients with evidenced chronic allograft dysfunction and over-immunosuppression leading to recurrent infections, dual maintenance immunosuppression with mycophenolate mofetil and corticosteroids may be appropriate. As stated in the annual report issued by the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) Registry, currently the most popular immunosuppressant protocol consists of a calcineurin inhibitor combined with mycophenolate mofetil and corticosteroids: 59.1% and 53.2% of patients with a functioning graft receive a calcineurin inhibitor plus mycophenolate mofetil plus corticosteroid-based immunosuppression at 1 and 5 years post-transplant, respectively. 91.4% and 87.8% of patients are administered a calcineurin inhibitor-containing regimen 1 and/or 5 years after transplantation, respectively. Undoubtedly, the use of calcineurin inhibitor-free immunosuppressant regimens with or without antibody induction, plus an mTOR inhibitor and mycophenolate mofetil, requires more comprehensive long-term investigations to determine whether acceptable rejection rates and conservation of renal function can be achieved.

Mortality risk in children after renal allograft failure: a NAPRTCS study

Studies have shown that adult dialysis patients with a failed renal allograft face a greater risk of mortality on dialysis compared with transplant-naïve patients. The outcome of children returning to dialysis after allograft failure has not been previously studied. Using the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) registry, we studied patients aged 2-21 years who initiated dialysis from 1 January 1992 to 31 December 2007. Of a total of 5,006 patients, 1,031 patients had a prior history of allograft failure and 3,975 did not (transplant-naïve). Demographic characteristics, including age at dialysis initiation, race, dialysis modality, primary renal disease, era of dialysis initiation, height Z score, and weight Z score were significantly different between the groups (p < 0.0001). Survival probability between the transplant-naïve and allograft failure groups was not significantly different (94.3% and 93.7% at 3 years respectively, log-rank p = 0.08). After covariate adjustment, allograft failure was not a significant factor contributing to increased mortality risk on dialysis (HR 0.98, CI 0.64-1.50, p = 0.94) based on Cox regression analysis. Children with failed allografts who return to dialysis are not at greater risk of mortality than their transplant-naïve dialysis counterparts.

Risk for anemia in pediatric chronic kidney disease patients: a report of NAPRTCS

Previous studies in children with chronic kidney disease (CKD) have identified low hemoglobin as a risk factor for poor outcomes. A retrospective review of the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) CKD registry was performed to identify the prevalence of and risk factors for anemia among children with stage 3 CKD, including both patients with low hemoglobin and those whose hemoglobin normalized with an erythropoiesis-stimulating agent (ESA). At enrollment, 2,792 patients had stage 3 CKD. Mean age was 9.5 (+/-0.11) years, 62.1% were male, 61.3% were white, and 43.7% had structural/urologic disease. Among 1,640 of those patients with 12 month follow-up data available for multivariate analysis, 73% met the criteria for anemia. Multivariate logistic regression analysis identifying risk factors for anemia at the 12-month follow-up revealed that, after controlling for estimated glomerular filtration rate, age >2 years, male sex, earlier era of study entry, and prescription of anti-hypertensive medications are associated with an increased risk for anemia at 12 months. In addition, multivariate Cox proportional hazards regression analysis revealed that when patients with ESA-corrected hemoglobin are included in the definition, anemia is not associated with increased risk of progression to end stage renal disease (dialysis initiation or transplantation).

The effect of rhGH on height velocity and BMI in children with CKD: a report of the NAPRTCS registry

The aim of this investigation was to evaluate the impact of recombinant human growth hormone (rhGH) therapy on height velocity (HV), estimated glomerular filtration rate (eGFR) and body mass index (BMI) in a large cohort of children with chronic kidney disease (CKD). We reviewed longitudinal data from patients enrolled in the chronic renal insufficiency registry of the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS). Of the 7189 patients enrolled in the registry, 827 (11.5%) received rhGH. A total of 787 children with CKD previously rhGH naïve who received rhGH for 1-4 years (median 1.5 years) were paired with 787 control patients, and over 100 of the case-controls were followed for 4 years. The control group was matched for age, gender, height and length of time in the NAPRTCS registry. Height velocity was also compared to the general U.S. population. The eGFR of the treated group (37.5 ml/min per 1.73 m(2)) was significantly less than that of the control group (42.3 ml/min per 1.73 m(2); p < 0.001). The rhGH-treated group had a significantly greater HV standard deviation score (SDS) than the control group (p < 0.01) at each 6-months post-rhGH treatment initiation point for 2.5 years (p < 0.007). Among 220 pairs at 2 years, the height SDS of the rhGH group was 0.56 SDS higher than that of the control group (p < 0.05). Treatment with rhGH had no significant impact on the BMI or eGFR. As demonstrated in smaller cohorts, rhGH usage is associated with improved HV in children with CKD. In contrast, rhGH does not appear to have any impact on BMI or kidney function in this population of patients.

Outcomes of kidney transplantation in children with nephronophthisis: An analysis of the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) Registry

NPHP is an autosomal recessive chronic tubulointerstitial nephropathy that progresses to ESRD. In the 2006 NAPRTCS report, NPHP was the primary diagnosis in 2.8% of all renal transplant patients. At our pediatric center, that covers a population in which the NPHP1 gene is prevalent, 24% of transplant recipients had a primary diagnosis of NPHP. Since no previous literature reports have documented kidney transplant outcomes in patients with NPHP, a review of the 2006 NAPRTCS database was performed. The results of this review illustrate that patients with NPHP as their underlying kidney disease have a significantly better overall graft survival when compared with all other patients registered in the NAPRTCS database. Sub-analysis demonstrated that this benefit is statistically significant only for LD kidney transplant recipients. CrCl was better in NPHP at all time points from transplant up to five-yr follow-up. Moreover, in NPHP LD transplant recipients the decline of CrCl over five yr was slower compared with non-NPHP LD transplant recipients. Rates of thrombosis, acute, and chronic rejection as well as causes of graft failure were similar in NPHP patients and all other patients. This review demonstrates that NPHP transplant recipients have excellent outcomes that are shown to be better compared with the general pediatric transplant population.

Progression From Acute Kidney Injury to Chronic Kidney Disease: A Pediatric Perspective

Although emerging evidence indicates that the incidence of both acute kidney injury (AKI) and chronic kidney disease (CKD) in children is rising and the etiologies are dramatically changing, relatively little is currently known regarding the potential for transition from AKI to CKD. In both situations, early intervention can significantly improve the dismal prognosis. However, the lack of a uniform AKI definition and the paucity of early, predictive biomarkers have impaired our ability diagnose AKI early to institute potentially effective therapies in a timely manner. Fortunately, recent data has validated a multidimensional AKI classification system for children. In addition, the application of innovative technologies has identified candidates that are emerging as early biomarkers of both AKI and CKD. These include neutrophil gelatinase-associated lipocalin, liver-type fatty acid-binding protein, and kidney injury molecule-1. Studies to validate the sensitivity and specificity of these biomarkers in clinical samples from large cohorts and from multiple clinical situations are currently in progress, facilitated by the development of commercial tools for the reproducible measurement of these biomarkers across different laboratories.

Use of rhGH in children with chronic kidney disease: lessons from NAPRTCS

We evaluated the utilization and potential benefits of recombinant human growth hormone (rhGH) in children with chronic kidney disease (CKD) and following renal transplantation in a large patient cohort. We queried the chronic renal insufficiency (CRI), dialysis, and transplant registries of the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) to characterize the frequency of rhGH utilization, factors related to its usage, and the relationship between rhGH usage and catch-up growth. Data from 6,505, 5,122, and 4,478 CRI, dialysis, and transplant patients, respectively, was evaluated. Percentage utilization of rhGH 2 years after registry entry was 22%, 33%, and 3% in children with a height standard deviation score (SDS)<-1 and age<17 years (termed candidate group) in CRI, dialysis, and transplant patients, respectively. Multivariate logistic regression analysis showed that the likelihood of using rhGH was significantly correlated with age, gender, geographical region of residence and height category within the candidate group (p<0.01). The use of rhGH was associated with catch-up growth in 27%, 11%, and 25% of candidate CRI, dialysis, and transplant patients, respectively. In the candidate group, percentage catch-up growth was highest in children who were Tanner stage 1-2, who comprised 19.4%, 7.1%, and 25.5% of the CRI, dialysis, and transplant patients, respectively. Using multiple regression analysis, the estimated impact of rhGH on final adult height (age>19 years) was 0.80, 0.50, and 0.19 SDS, in CRI, dialysis, and transplant patients, respectively. Thus, rhGH can improve height gain in some children with CKD. The use of rhGH appears to be most effective in prepubertal children with CRI.

Racial Differences in Graft Survival

Multiple studies have documented racial differences in graft survival in kidney transplant recipients. Although several studies in adult kidney transplant recipients have evaluated risk factors that might predispose to these differences, studies in pediatric patients are lacking. This study retrospectively analyzed data from the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) to identify racial differences in kidney transplant outcomes and evaluate factors that might contribute to those differences. The study was restricted to the first NAPRTCS registry-reported kidney transplant for pediatric patients (age < or =21 yr) whose race was reported as either black or white. Univariate graft survival analyses were performed using the log rank statistic. Relative hazard rates for the effect of race on graft failure were determined using proportional hazards models. Multivariate analyses were restricted to patients with >30 d of graft survival and were adjusted for initial diagnosis, donor source, presence of delayed graft function, era of transplantation, estimated GFR at 30 d after transplantation, and number of days hospitalized in the first month after transplantation. Graft survival was significantly lower in black transplant recipients at 3 yr (70.9 versus 83.3%) and 5 yr (59.9 versus 77.7%). After controlling for confounding factors, black recipients continued to have a higher risk for graft failure than white recipients (adjusted hazard rate 1.65; 95% confidence interval 1.46 to 1.86). Significant racial differences in kidney transplant outcomes exist among pediatric patients even after controlling for confounding factors.

Contributions of the Transplant Registry: The 2006 Annual Report of the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS)*

This summary of the NAPRTCS 2006 Annual Report of the Transplant Registry highlights the significant impact the registry has had in advancing knowledge in pediatric renal transplantation worldwide. This cooperative group has collected clinical information on children undergoing a renal transplantation since 1987 and now includes over 150 participating medical centers in the USA, Canada, Mexico, and Costa Rica. Currently, the NAPRTCS transplant registry includes information on 9837 renal transplants in 8990 patients (NAPRTCS 2006 Annual Report). Since the first data analysis in 1989, NAPRTCS reports have documented marked improvements in outcome after renal transplantation in addition to identifying factors associated with both favorable and poor outcomes. The registry has served to document and influence practice patterns, clinical outcomes, and changing trends in renal transplantation.