Two decades of pediatric kidney transplantation in a multi-ethnic cohort

Risk factors for end stage renal disease in children with anorectal malformation and outcome comparison to children with isolated urological anomalies

BACKGROUND

End stage renal disease (ESRD) requiring kidney transplant (KT) remains an important cause of morbidity in anorectal malformations (ARM) patients. Current literature is scarce on defining the risk factors for ESRD and the outcomes of KT in ARM patients.

OBJECTIVE

This study aimed to identify predisposing factors to ESRD in ARM patients and verify if the long term outcome of KT in these patients differs from pure urological anomalies (UA).

STUDY DESIGN

Databases of ARM and KT patients treated at our center between 2000 and 2016 were used for comparing characteristics of ARM cases which developed ESRD and those who did not, and the outcome features of MAR-KT vs UA-KT.

RESULTS

Out of 117 ARM patients, 9 developed ESRD. All of them had a complex ARM. Association with UA were significantly higher in ARM-KT compared to other ARM patients (100% vs. 52%, p = 0.001). The most common UA associated to KT in ARM patients was renal dysplasia. During the same period 23 patients underwent KT as a sequelae of pure urological anomalies (UA-KT group). The most represented UA were primary vesico-ureteral reflux (65.2%) and posterior urethral valves (14%) in UA-KT (table 2). ARM-KT patients required more often hemodialysis before KT (50% vs. 8.7%, p = 0.05) and an aorto-caval anastomosis at the transplant (75% vs. 30%, p = 0.04) compared to UA-KT. Moreover ARM-KT patients experienced more often graft failure and and the need for a second KT (50% vs. 8.6%, p = 0.02).

DISCUSSION

To our knowledge, this is the first study describing the differences in terms of risk factors and outcomes of KT in ARM patients. We observed a need for KT in 7% of ARM, which is at the higher end of the range reported in the literature. Bilateral dysplasia and cloaca malformation seem the leading cause to ESRD for ARM patients compared to vesico-ureteral reflux and posterior urethral valve in UA-KT. Our experience showed that KT has worst outcome in ARM vs pure UA patients.

CONCLUSION

Patients with complex ARM are more frequently associated to renal dysplasia which lead to KT. Graft in ARM patients seems to be the more vulnerable and prone to failure.

Associations between Deprivation, Geographic Location, and Access to Pediatric Kidney Care in the United Kingdom

BACKGROUND AND OBJECTIVES

Pre-emptive kidney transplantation is advocated as best practice for children with kidney failure who are transplant eligible; however, it is limited by late presentation. We aimed to determine whether socioeconomic deprivation and/or geographic location (distance to the center and rural/urban residence) are associated with late presentation, and to what degree these factors could explain differences in accessing pre-emptive transplantation.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A cohort study using prospectively collected United Kingdom Renal Registry and National Health Service Blood and Transplant data from January 1, 1996 to December 31, 2016 was performed. We included children aged >3 months to ≤16 years at the start of KRT. Multivariable logistic regression models were used to determine associations between the above exposures and our outcomes: late presentation (defined as starting KRT within 90 days of first nephrology review) and pre-emptive transplantation, with a priori specified covariates.

RESULTS

Analysis was performed on 2160 children (41% females), with a median age of 3.8 years (interquartile range, 0.2-9.9 years) at first nephrology review. Excluding missing data, 478 were late presenters (24%); 565 (26%) underwent pre-emptive transplantation, none of whom were late presenting. No association was seen between distance or socioeconomic deprivation with late presentation, in crude or adjusted analyses. Excluding late presenters, greater area affluence was associated with higher odds of pre-emptive transplantation, (odds ratio, 1.20 per quintile greater affluence; 95% confidence interval, 1.10 to 1.31), with children of South Asian (odds ratio, 0.52; 95% confidence interval, 0.36 to 0.76) or Black ethnicity (odds ratio, 0.31; 95% confidence interval, 0.12 to 0.80) less likely to receive one. A longer distance to the center was associated with pre-emptive transplantation on crude analyses; however, this relationship was attenuated (odds ratio, 1.02 per 10 km; 95% confidence interval, 0.99 to 1.05) in the multivariable model.

CONCLUSIONS

Socioeconomic deprivation or geographic location are not associated with late presentation in children in the United Kingdom. Geographic location was not independently associated with pre-emptive transplantation; however, children from more affluent areas were more likely to receive a pre-emptive transplant.

An overview of disparities and interventions in pediatric kidney transplantation worldwide

Despite the stated goals of the transplant community and the majority of organ allocation systems, persistent racial disparities in pediatric kidney transplantation exist throughout the world. These disparities are evident in both living and deceased donor kidney transplantation and are independent of any clinical differences between racial groups. The reasons for these persistent disparities are multifactorial, reflecting both patient and provider barriers to care. In this review, we examine the most current findings regarding disparities in pediatric kidney transplantation and consider interventions which may help reduce those disparities.

Racial and ethnic disparities in pediatric renal allograft survival in the United States

This study was undertaken to describe the association of patient race/ethnicity and renal allograft survival among the national cohort of pediatric renal allograft recipients. Additionally, we determined whether racial and ethnic differences in graft survival exist among individuals living in low or high poverty neighborhoods and those with private or public insurance. Among 6,216 incident, pediatric End Stage Renal Disease patients in the United States Renal Data System (kidney transplant from 2000 through September, 2011) 14.4% experienced graft failure, with a median follow-up time of 4.5 years. After controlling for multiple covariates, black race, but not Hispanic ethnicity, was significantly associated with a higher rate of graft failure for both deceased and living donor transplant recipients. Disparities were particularly stark by 5 years post-transplant, when black living donor transplant recipients experienced only 63.0% graft survival compared with 82.8% and 80.8% for Hispanics and whites, respectively. These disparities persisted among high and low poverty neighborhoods and among both privately- and publicly-insured patients. Notably profound declines in both deceased and living donor graft survival rates for black, compared to white and Hispanic, children preceded the 3-year mark when transplant Medicare eligibility ends. Further research is needed to identify the unique barriers to long-term graft success among black pediatric transplant recipients.

Racial disparities in paediatric kidney transplantation

BACKGROUND

Transplantation is the preferred treatment for children with end-stage kidney disease (ESKD). Pre-emptive transplants, those from live donors and with few human leukocyte antigen (HLA) mismatches provide the best outcomes. Studies into disparities in paediatric transplantation to date have not adequately disentangled different transplant types.

METHODS

We studied a retrospective cohort of 823 patients aged <18 years who started renal replacement therapy (RRT) in Australia 1990-2011, using the Australia and New Zealand Dialysis and Transplant Registry (ANZDATA). The primary outcomes were time to first kidney transplant and kidney donor type (deceased or living), analysed using competing risk regression.

RESULTS

Caucasian patients were most likely to receive any transplant, due largely to disparities in live donor transplantation. No Indigenous patients received a pre-emptive transplant. Indigenous patients were least likely to receive a transplant from a live donor (sub-hazard ratio 0.41, 95 % confidence interval 0.20-0.82, compared to Caucasians). Caucasian recipients had fewer HLA mismatches, were less sensitised and were more likely to have kidney diseases that could be diagnosed early or progress slowly.

CONCLUSIONS

Caucasian paediatric patients are more likely to receive optimum treatment--a transplant from a living donor and fewer HLA mismatches. Further work is required to identify and address barriers to live donor transplantation among minority racial groups.

Surgical complications and graft survival in pediatric kidney transplant recipients treated with a steroid-free protocol: experiences from a Danish university hospital

BACKGROUND

The outcome of pediatric kidney transplantation depends on several factors, among these are the complications, which occur in relation to the surgical procedure. In this study, we present our experience with pediatric kidney transplantation in a steroid-free immunosuppression regimen, from a surgical point of view.

METHODS

Patient charts of pediatric kidney transplantations in the period 1998-2011 were reviewed. Surgical complications, acute rejection, and patient and graft survivals were recorded.

RESULTS

Sixty-one renal transplantations were performed in 58 patients. Thirty patients (49.1%) experienced a surgical complication, of which 11 (18%) required an explorative laparotomy. Overall the five-year Kaplan-Meier patient survival rate was 96.2% and the graft survival rate was 88.6%. Nine patients (14.7%) had an acute rejection episode within the first year after transplantation. No correlation was observed between surgical complications and acute rejection episodes or graft loss.

CONCLUSIONS

This study indicated a high incidence of surgical complications among pediatric kidney transplantations when using a steroid-free immunosuppression regimen. Despite this, we observed high overall patient and graft survival, supporting the trend toward steroids avoidance in pediatric kidney transplantation.

Racial disparities in access to pediatric kidney transplantation since share 35

Share 35 was enacted in 2005 to shorten transplant wait times and provide high-quality donors to children with ESRD. To investigate the possible effect of this policy on racial disparities in access to pediatric transplantation, we analyzed data from the US Renal Data System before and after Share 35. Among 4766 pediatric patients with incident ESRD, the probability of receiving a deceased-donor kidney transplant increased 46% after Share 35, with Hispanics experiencing the greatest improvements (increases of 81% for Hispanics, 45% for blacks, and 37% for whites). On average, patients received a deceased-donor kidney transplant earlier after Share 35, but this finding varied by race: 63 days earlier for whites, 90 days earlier for blacks, and 201 days earlier for Hispanics. Furthermore, a shift from living- to deceased-donor sources occurred with Share 35 for all races, with a 25% reduction in living donors for whites compared with 48% and 46% reductions for Hispanics and blacks, respectively. In summary, Share 35 seems to have attenuated racial disparities in the time to and probability of children receiving a deceased-donor kidney transplant. These changes coincided with changes in the rates of living-donor sources, which vary by race. Future studies should explore how these changes may impact racial differences in long-term graft outcomes.

Adherence of pediatric patients to automated peritoneal dialysis

Little information is available on adherence to a home automated peritoneal dialysis (APD) prescription for children with end-stage renal disease. We have therefore retrospectively reviewed HomeChoice PRO Card data from patients <21 years of age who received home APD. Adherence was characterized as occurring ≥ 95%, 90-94%, or <90% of time by dividing the frequency of each of four measured prescription variables (sessions/month, duration of each session, number of cycles/session, volume of dialysate/session) by the prescribed frequency and multiplying by 100. The relationship between treatment adherence and patient age, gender, race and if the patient had received training, respectively, was assessed. Of the 51 patients (57% male), with a mean age at peritoneal dialysis (PD) onset of 11.8 ± 5.3 years, 28 (55%) were adherent for all variables. No difference in mean age or if patients were trained existed between the two groups. Males were more likely to be non-adherent (p = 0.026) as were African Americans (p = 0.048). The majority of patients were adherent to duration (96%) and number of cycles (92%), whereas non-adherence was more common with number of sessions (82%) and dialysate volume (78%). In conclusion, 45% of the pediatric patients in our study cohort exhibited some non-adherence to their prescribed APD regimen, emphasizing the value of closely monitoring the performance of home dialysis in children.

Tertiary excess of fibroblast growth factor 23 and hypophosphatemia following kidney transplantation

Hypophosphatemia caused by inappropriate urinary phosphate wasting is a frequent metabolic complication of the early period following kidney transplantation. Although previously considered to be caused by tertiary hyperparathyroidism, recent evidence suggests a primary role for persistently elevated circulating levels of the phosphorus-regulating hormone, FGF23. In the setting of a healthy renal allograft, markedly increased FGF23 levels from the dialysis period induce renal phosphate wasting and inhibition of calcitriol production, which contribute to hypophosphatemia. While such tertiary FGF23 excess and resultant hypophosphatemia typically abates within the first few weeks to months post-transplant, some recipients manifest persistent renal phosphate wasting. Furthermore, increased FGF23 levels have been associated with increased risk of kidney disease progression, cardiovascular disease, and death outside of the transplant setting. Whether tertiary FGF23 excess is associated with adverse transplant outcomes is unknown. In this article, we review the physiology of FGF23, summarize its relationship with hypophosphatemia after kidney transplantation, and speculate on its potential impact on long-term outcomes of renal allograft recipients.