Survival and transplant outcomes among young children requiring kidney replacement therapy

Time-Varying Determinants of Graft Failure in Pediatric Kidney Transplantation in Europe

BACKGROUND

Little is known about the time-varying determinants of kidney graft failure in children.

METHODS

We performed a retrospective study of primary pediatric kidney transplant recipients (younger than 18 years) from the Eurotransplant registry (1990-2020). Piece-wise exponential additive mixed models were applied to analyze time-varying recipient, donor, and transplant risk factors. Primary outcome was death-censored graft failure.

RESULTS

We report on 4528 kidney transplantations, of which 68% with deceased and 32% with living donor. One thousand six hundred and thirty-eight recipients experienced graft failure, and 168 died with a functioning graft. Between 2011 and 2020, the 5-year graft failure risk was 10% for deceased donor and 4% for living donor kidney transplant recipients. Risk of graft failure decreased five-fold from 1990 to 2020. The association between living donor transplantation and the lower risk of graft failure was strongest in the first month post-transplant (adjusted hazard ratio, 0.58; 95% confidence interval, 0.46 to 0.73) and remained statistically significant until 12 years post-transplant. Risk factors for graft failure in the first 2 years were deceased donor younger than 12 years or older than 46 years, potentially recurrent kidney disease, and panel-reactive antibody >0%. Other determinants of graft failure included dialysis before transplantation (until 5 years post-transplant), human leukocyte antigen mismatch 2-4 (0-15 years post-transplant), human leukocyte antigen mismatch 5-6 (2-12 years post-transplant), and hemodialysis (8-14 years post-transplant). Recipients older than 11 years at transplantation had a higher risk of graft failure 1-8 years post-transplant compared with other age groups, whereas young recipients had a lower risk throughout follow-up. Analysis of the combined effect of post-transplant time and recipient age showed a higher rate of graft failure during the first 5 years post-transplant in adolescents compared with young transplant recipients. In contrast to deceased donor younger than 12 years, deceased donor older than 46 years was consistently associated with a higher graft failure risk.

CONCLUSIONS

We report a long-term inverse association between living donor kidney transplantation and the risk of graft failure. The determinants of graft failure varied with time. There was a significant cumulative effect of adolescence and time post-transplant. The ideal donor age window was dependent on time post-transplant.

Epidemiology and Outcomes of Children with Kidney Failure Receiving Kidney Replacement Therapy in Australia and New Zealand

Introduction

The incidence and outcomes of kidney replacement therapy (KRT) have been well-studied in adults, but much less so in children. This study aimed to investigate the epidemiology and outcomes of KRT in children in Australia and New Zealand from 2000 to 2020.

Methods

Children aged <18 years initiating KRT in Australia and New Zealand between January 1, 2000 and December 31, 2020 and reported to the Australia and New Zealand Dialysis and Transplant Registry were included. Patient survival, technique-survival, and graft survival were analyzed by Cox regression analyses.

Results

Overall, 1058 children (median [interquartile range (IQR)] age 11 [5-15] years, 41% female, 66% White) were followed-up with for a median period of 12.3 years. First KRT modalities were peritoneal dialysis (PD; 48%), hemodialysis (HD; 34%), and kidney transplantation (KT; 18%). Pre-emptive KT incidence was highest in Caucasian children (80.4%) and lowest in the Indigenous population (3.2%). There was no difference in 5-year patient survival rates between 2011 and 2020 (96.9%, 95% confidence interval [CI] 93.8-98.4) and the preceding decade, 2000-2010 (94.5%, 95% CI 90.4-96.8) (P = 0.79). There was no difference in 5-year death-censored technique survival between 2011 and 2020 (51.2%, 95% CI 39.1-62) and 2000-2010 (48.8%, 95% CI 40.5-56.6) (P = 0.27). However, 5-year derath-censored graft survival was significantly higher in 2011-2020 (88.4%, 95% CI 84.6-91.4) than in 2000-2010 (84.3%, 95% CI 80.4-87.5) (P < 0.001).

Conclusions

PD is the most commonly prescribed KRT modality for children in Australia and New Zealand. Patient-survival, technique-survival, and graft survival rates are excellent and graft survival has improved over the last 2 decades.

A Multi-Step Precision Pathway for Predicting Allograft Survival in Heterogeneous Cohorts of Kidney Transplant Recipients

Accurate prediction of allograft survival after kidney transplantation allows early identification of at-risk recipients for adverse outcomes and initiation of preventive interventions to optimize post-transplant care. Many prediction algorithms do not model cohort heterogeneity and may lead to inaccurate assessment of longer-term graft outcomes among minority groups. Using data from a national Australian kidney transplant cohort (2008-2017) as the derivation set, we developed P-Cube, a multi-step precision prediction pathway model for predicting overall graft survival in three ethnic subgroups: European Australians, Asian Australians and Aboriginal and Torres Strait Islander Peoples. The concordance index for the European Australians, Asian Australians, and Aboriginal and Torres Strait Islander Peoples subpopulations were 0.99 (0.98-0.99), 0.93 (0.92-0.94) and 0.92 (0.91-0.93), respectively. Similar findings were observed when validating P-cube using an external dataset [Scientific Registry of Transplant Recipient Registry (2006-2020)]. Six sub-categories of recipients with distinct risk factor profiles were identified. Some factors such as blood group compatibility were considered important across the entire transplant population. Other factors such as human leukocyte antigen (HLA)-DR mismatches were unique to older recipients. The P-cube model identifies allograft survival specific risk factors within a heterogenous population and offers personalized survival predictions in a diverse cohort.

Timing of Kidney Replacement Therapy among Children and Young Adults

BACKGROUND

No randomized trials exist to guide the timing of the initiation of KRT in children. We sought to define trends and predictors of the eGFR at initiation of KRT, center-related clinical practice variation, and any association with patient survival.

METHODS

Children and young adults (1-25 years) commencing KRT (dialysis or kidney transplantation) between 1995 and 2018 were included using data from the Australia and New Zealand Dialysis and Transplant Registry. The associations between eGFR on commencing KRT and covariates were estimated using quantile regression. Cox regression was used to estimate the association between eGFR and patient survival. Logistic regression, categorizing eGFR about a value of 10 ml/min per 1.73 m 2 , was used in conjunction with a random effect by center to quantify clinical practice variation.

RESULTS

Overall, 2274 participants were included. The median eGFR at KRT initiation increased from 7 to 9 ml/min per 1.73 m 2 over the study period and the 90th centile from 11 to 17 ml/min per 1.73 m 2 . The effect of era on median eGFR was modified by modality, with a greater increase among those receiving a preemptive kidney transplant (1.0 ml/min per 1.73 m 2 per 5 years; 95% confidence interval [CI], 0.6 to 1.5) or peritoneal dialysis (0.7 ml/min per 1.73 m 2 per 5 years; 95% CI, 0.4 to 0.9) compared with hemodialysis (0.1 ml/min per 1.73 m 2 per 5 years; 95% CI, -0.1 to 0.3). There were 252 deaths (median follow-up 8.5 years, interquartile range 3.7-14.2) and no association between eGFR and survival (hazard ratio, 1.01 per ml/min per 1.73 m 2 ; 95% CI, 0.98 to 1.04). Center variation explained 6% of the total variance in the odds of initiating KRT earlier. This rose to over 10% when comparing pediatric centers alone.

CONCLUSIONS

Children and young adults progressively commenced KRT earlier. This change was more pronounced for children starting peritoneal dialysis or receiving a preemptive kidney transplant. Earlier initiation of KRT was not associated with any difference in patient survival. A substantial proportion of clinical practice variation was due to center variation alone.

PODCAST

This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/CJASN/2023_08_08_CJN0000000000000204.mp3.

Evaluation of pediatric renal transplant recipients admitted to the intensive care unit: A retrospective cohort study

Background/Aim: The best course of treatment for children with end-stage kidney disease (ESKD) is renal transplantation (RT), but some pediatric RT recipients are admitted to an intensive care unit (ICU) post-transplant. In the early and late post-operative phases, clinical data about pediatric RT recipients who are admitted to ICU are available. In this study, we aimed to evaluate demographic features, main reasons, and outcomes of pediatric RT patients admitted to the ICU during the early and late post-operative phases. Methods: This study was a cohort study. We analyzed the medical records of pediatric RT recipients (<18 years of age) who were admitted to the ICU between May 30, 2011, and October 16, 2021, at our center, retrospectively. Patients ≥18 years of age and those without available data were excluded. We obtained the following data from ICU follow-up records and hospital medical records. The median (minimum-maximum) for continuous variables, frequencies, and percentages for categorical variables were used. The Chi-square test was used to compare categorical variables. We created graphs using percentages and frequencies to summarize the results. Results: Nineteen (16.5%) of the 115 pediatric patients who underwent RT were admitted to the ICU during the study period. Thirteen patients (68.4%) were male, and the mean age was 10.2 (4.9) years. Hypertension (21.2%) was the most common comorbidity. Eighteen (94.7%) received transplants from living donors. Cystic-hereditary-congenital disorders (42.1%, n=8) and congenital anomalies of the kidney and urinary tract (26.3%, n=5) were among the etiologies of ESKD. Ten patients (52.6%) were admitted to the ICU >6 months after transplantation. Epileptic seizure (n=6, 31.6%), respiratory failure (n=4, 21.1%), and cardiac diseases (n=2, 10.5%) were among the main reasons for ICU admission. During ICU follow-up, invasive mechanical ventilation was needed for five patients (26.3%), and renal replacement treatment was needed for four patients (21.1%). The mean length of ICU was 12.4 (28.5), and the mean hospital stay was 25.8 (29.4) days. The ICU and hospital survival rates were 78.9% and 97%, respectively, while 3.5% was the hospital mortality rate. Hemorrhagic cerebrovascular disease, acute hepatic failure, and cardiogenic shock secondary to pericardiocentesis were the causes of death in the ICU. Conclusion: Patients mostly had ICU admissions because of epileptic seizures and acute respiratory failure. A multidisciplinary approach involving pediatric nephrologists, transplant surgeons, and an intensive care team successfully manages pediatric RT recipients admitted to the intensive care unit.

Survival analysis among pediatric patients receiving kidney replacement therapy: a Japanese nationwide cohort study

BACKGROUND

Limited data are available on the survival and causes of death in pediatric patients with chronic kidney disease (CKD) stage 5 receiving kidney replacement therapy (KRT) in Asia.

METHODS

Data were obtained from the Japanese nationwide cross-sectional CKD stage 5 survey on pediatric patients (<20 years of age) who started KRT from 2006 to 2013. The cohort was divided into three groups according to age at the start of KRT: <1, 1-5, and 6-19 years.

RESULTS

Among the 701 children who were included, 59.3% were boys. Peritoneal dialysis was the most common initial modality of KRT (60.3%). Median age at KRT initiation was 10.2 years. Infants (<1 year old) accounted for 16.0% of the total cohort. Overall survival at 1 and 5 years was 97.2% and 92.5%, respectively. Infants had significantly lower survival rates than the other groups (hazard ratio, 5.35; 95% CI, 2.60-11.03; P < 0.001). In contrast, after the age of 1 year, the survival rate improved and did not differ from that of other age groups. The most common causes of death were infection (35.9%) and sudden death (15.4%).

CONCLUSIONS

The overall survival rate of pediatric patients with CKD stage 5 in Japan is like that in other high-income countries. Age at initiation of KRT is an important factor affecting survival since the poorest survival rate was observed in infants. Further improvement in infant dialysis therapy is still needed to improve survival of the youngest children. A higher resolution version of the Graphical abstract is available as Supplementary information.

Changes in graft function after living donor kidney transplantation in children

BACKGROUND

This study aimed to evaluate the change in graft function in two groups stratified by the estimated glomerular filtration rate (eGFR) at 1 month after transplantation (eGFR-1 M) in pediatric living donor kidney transplant recipients.

METHODS

Forty-three pediatric recipients were classified as those with an eGFR-1 M ≥ 90 mL/min/1.73 m² (n = 19; high eGFR group) or those with an eGFR-1 M of 60-89 mL/min/1.73 m² (n = 24; middle eGFR group). In the two groups, changes in the eGFR were retrospectively evaluated for 5 years after kidney transplantation.

RESULTS

The mean recipient age at transplantation in the high/middle eGFR group was 6.1 ± 3.4/7.8 ± 4.0 years (P = 0.14). The mean eGFR-1, -12, and -60 M (mL/min/1.73 m²) in the high/middle eGFR group were 106.8 ± 2.99/78.5 ± 1.52 (P < 0.001), 79.3 ± 3.22/62.7 ± 2.38 (P < 0.001), and 73.1 ± 4.16/59.2 ± 2.79 (P = 0.006), respectively. The change in the mean eGFR remained mostly parallel in the two groups. In both groups, the eGFR significantly decreased only between 1 and 12 months after transplantation (P < 0.0001). Approximately 70% of the patients had an eGFR-60 M ≥ 60 mL/min/1.73 m².

CONCLUSIONS

The high and middle eGFR groups showed a rapid decline in the eGFR by 1 year after transplantation, but the change thereafter was gradual. In pediatric living donor kidney transplant recipients, the eGFR was relatively well maintained up to 5 years after transplantation. A higher resolution version of the Graphical abstract is available as Supplementary information.