Timing of Kidney Replacement Therapy among Children and Young Adults

Background: No randomized trials exist to guide timing the initiation of kidney replacement therapy (KRT) in children. We sought to define trends and predictors of the estimated glomerular filtration rate (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 utilizing 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 10ml/min/1.73m2, was used in conjunction with a random effect by center to quantify clinical practice variation. Results: Overall, 2274 participants were included. The median eGFR increased from 7ml/min/1.73m2 to 9ml/min/1.73m2 over the study period, and the 90th centile from 11ml/min/1.73m2 to 17ml/min/1.73m2. The effect of era on median eGFR was modified by modality, with a greater increase among those receiving a pre-emptive kidney transplant (1.0ml/min/1.73m2 per 5 years, 95%CI 0.6 to 1.5) or peritoneal dialysis (0.7ml/min/1.73m2 per 5 years, 95%CI 0.4 to 0.9), compared to hemodialysis (0.1ml/min/1.73m2 per 5 years, 95%CI -0.1 to 0.3). There were 252 deaths (median follow-up 8.5 years, IQR 3.7 to 14.2), and no association between eGFR and survival (HR 1.01 per ml/min/1.73m2, 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 pre-emptive 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.