Adult outcomes of childhood kidney replacement therapy in Europe from 2008 to 2019: an ERA Registry study

Young adults starting kidney replacement therapy (KRT) during childhood and reaching their 18th birthday (i.e. adult survivors of childhood KRT) form a challenging population of interest to nephrologists treating adults, as during this period there will be a transition to adult renal centres. Nonetheless, few studies have focused on the epidemiology of KRT in this group. We aimed to provide an update on these patients' characteristics, treatment history, and graft and patient survival, to report their 5-year prognosis and expected remaining lifetime.

Data on KRT patients reaching their 18th birthday in 2008-19 were collected from 21 European countries/regions providing individual patient data to the European Renal Association (ERA) Registry. Patient characteristics and treatment trajectories were examined before and after turning 18 years old. Kaplan-Meier and Cox proportional hazards regression were used for patient and graft survival analyses.

In total, 2944 patients were included. The proportion of adult survivors initiating KRT at a very young age (0-4 years) and undergoing pre-emptive kidney transplantation increased. Unadjusted 5-year patient survival was 96.9% [95% confidence interval (CI) 96.2-97.5]. Dialysis patients had a higher risk of death than kidney transplant recipients [adjusted hazard ratio 5.44 (95% CI 3.34-8.86)]. Between ages 18 and 23 years, about 21% of the adult survivors lost their kidney transplant and 34% of the dialysis patients continued this treatment. Compared with the general population, life expectancy for 18-year-old kidney transplant and dialysis patients was 17 and 40 years shorter, respectively.

Life expectancy of 18-year-old kidney transplant recipients was lower compared with the general population, yet having a functioning kidney graft at age 18 years resulted in better outcomes than being on dialysis. Nevertheless, between ages 18 and 23 years, about one-fifth of the kidney grafts failed and one-third of the patients remained on dialysis.