Trajectory of kidney recovery in pediatric patients requiring continuous kidney replacement therapy for acute kidney injury

Background Acute kidney injury (AKI) is commonly seen in the PICU and is associated with poor short-term and long-term outcomes, especially in patients who required continuous kidney replacement therapy (CKRT). However, as the trajectory of kidney recovery in these patients remain uncertain, determination of the timing to convert to permanent kidney replacement therapy (KRT) remains a major challenge. We aimed to examine the frequency and timing of kidney recovery in pediatric AKI survivors that required CKRT. Methods We performed a retrospective study of patients under 18 years old who received CKRT for AKI in a tertiary-care PICU over 6 years. Primary outcomes were the rate of KRT withdrawal due to kidney recovery and KRT-dependent days for those who survived to hospital discharge. Secondary outcomes were all-cause mortality, dialysis dependence, and occurrences of estimated glomerular filtration rate (eGFR) < 90 mL/min/1.73m(2) and eGFR < 60 mL/min/1.73m(2) one year after initiation of the index CKRT in survivors. Results Thirty-nine patients were included. Of the 28 children who survived to hospital discharge, 26 (93%) withdrew from dialysis due to kidney recovery, all within 30 days. Twenty-three patients were followed up. One had died, five had an eGFR of 60 mL/min/1.73m(2) or more but less than 90 mL/min/1.73m(2), and two had an eGFR < 60 mL/min/1.73m(2), of which one required peritoneal dialysis. Conclusions Over 90% of the survivors withdrew CKRT within 30 days. However, the frequency of abnormal eGFR one year after initiation of CKRT in survivors exceeded 30% and supports the recommendation of post-AKI follow-up.