Fluid accumulation and outcomes in children receiving continuous kidney replacement therapy: an appraisal of the WE-ROCK registry

BACKGROUND: The prospective pediatric Continuous Renal Replacement Therapy (ppCRRT) registry identified the degree of fluid accumulation (FA) at continuous kidney replacement therapy (CKRT) initiation as a predictor of adverse outcomes in children. These predate major advancements in CKRT technology and fluid stewardship. We aimed to describe the epidemiology of FA at CKRT initiation and associated outcomes in a contemporary paediatric cohort.

METHODS: Secondary analysis of Worldwide Exploration of Renal Replacement Outcomes Collaborative in Kidney Disease (WE-ROCK), a retrospective, multicenter study (35 centers, 9 countries) of patients ≤ 25 years treated with CKRT from 2015 to 2021.

PRIMARY OUTCOME: survival to ICU discharge.

SECONDARY OUTCOMES: ventilator-free and ICU-free days.

RESULTS: A total of 1027 patients were included in this analysis. Survival to ICU discharge was 64.5% (n = 663). Median FA at CKRT initiation was 7.4% (IQR 2.4-18.1). FA differed between ICU survivors and non-survivors (7% [IQR 2-17] vs. 9% [IQR 3-21], p = 0.004). At CKRT initiation, 605 patients (58.9%) had FA < 10%, 194 patients (18.9%) had 10%-20% FA, and 228 patients (22.2%) had > 20% FA. In multivariable analysis, FA at CKRT initiation was not associated with ICU mortality but was associated with fewer ventilator (aOR 0.84, 95%CI 0.76-0.94, p = 0.023) and ICU-free days (aOR 0.6, 95%CI 0.49-0.73, p < 0.001).

CONCLUSIONS: The current study provides a contemporary evaluation of the epidemiology and impact of FA at CKRT initiation on outcomes in a cohort of > 1000 children treated with CKRT for FA/AKI. Clinically significant FA remains common at CKRT initiation and is associated with outcomes. This contemporary data can be used to inform clinical care and plan prospective studies.