#364 Patient characteristics, treatment history and prognosis of adult survivors of childhood kidney replacement therapy—an ERA Registry study
Authors: de Sousa Iris R Montez , Bonthuis Marjolein , Kramer Anneke , Ortiz Alberto , Rydell Helena , Groothoff Jaap W , Bakkaloglu Sevcan A , Sørensen Søren S , Stel Vianda , Jager Kitty J 
Published: May 2024

Abstract

Background and Aims
Young adults who initiated kidney replacement therapy (KRT) during childhood and reached their 18th birthday (i.e. adult survivors of childhood KRT) are a particularly challenging patient group. Besides the changes associated with adolescence, they go through a transition from paediatric to adult nephrology centres, in which patients are expected to take responsibility of their own care. This increases the risk of non-compliance to treatment and graft failure. Nevertheless, not many epidemiological studies have focused on adult survivors of childhood KRT. This type of study would support healthcare providers in obtaining knowledge about the prognosis of this patient group and, perhaps, recognizing possibilities of treatment improvements. We aimed to provide up-to-date information on patient characteristics, treatment history, (graft) survival, 5-year prognosis and expected remaining lifetime of adult survivors of childhood KRT.

Method
KRT data was used from 21 European countries/regions that contributed with individual patient data to the European Renal Association (ERA) Registry. Adult survivors of childhood KRT, reaching the age of 18 years between 2008 and 2019, were included in the analysis, and their patient characteristics and treatment trajectories were examined. Kaplan-Meier and Cox proportional hazards regression were used in patient and graft survival analyses. The expected remaining lifetime of all KRT patients from the age of 18 years onwards was calculated overall and stratified by sex and treatment modality at the 18th birthday.

Results
We included 2 944 patients in the analysis, most of them were 10-14 (32.9%) or 15-17 (30.6%) years at start of KRT, and congenital anomalies of the kidney and urinary tract (CAKUT) were the most frequent cause of kidney failure (38.8%). Peritoneal dialysis was the most common treatment at start of KRT (37.8%), yet the percentage of adult survivors who received a pre-emptive kidney transplant increased from 25.6% in 2008-2011 to 32.4% in 2016-2019. By their 18th birthday, 81.4% of patients had a functioning kidney transplant. The overall unadjusted 5-year patient survival after their 18th birthday was 96.9% (95% CI 96.2-97.5), yet adult survivors on dialysis had an almost 4 times higher risk of death than their peers with a functioning kidney graft (adjusted HR 3.76 (95% CI: 2.55-5.53)). Besides, about 21% of the grafts failed during the 5 years after the 18th birthday (unadjusted 5-year graft survival: 78.9% (95% CI: 77.1-80.7)). Eighteen-year-old kidney transplant recipients reached 74% of the expected remaining lifetime of the general population, whereas dialysis patients only reached 37%.

Conclusion
Even at the young age of 18 years the remaining life expectancy of kidney transplant recipients was lower compared with the general population, and about one fifth of the grafts failed within 5 years after the patients’ 18th birthday. Still, as expected, adult survivors with a functioning kidney transplant at 18 years showed better outcomes than the ones on dialysis, with a greater 5-year survival and longer life expectancy. This epidemiological study reports on one of the biggest cohorts of adult survivors of childhood KRT studied to date. It provides unique knowledge on the prognosis of these patients, establishing the first step towards the optimization of care in this challenging patient group.