Functional outcomes in pediatric patients on renal replacement therapy in a worldwide registry

Background and hypothesis Mortality rates of children supported with continuous renal replacement therapy (CRRT) have improved, yet morbidity remains high. We aimed to evaluate the functional outcomes of children receiving CRRT using Functional Status Scale (FSS). We hypothesized that children receiving CRRT will have worse FSS compared with their baseline and acquire new morbidity at hospital discharge and 6 and 12 months post-discharge, and that lack of renal recovery will contribute to worsening functional status. Methods This is a retrospective chart review from The Worldwide Exploration of Renal Replacement Outcomes Collaborate in Kidney Disease (WE-ROCK), an international multi-center registry. Twenty-eight centers across five countries participated in this analysis. Children from birth to 25 years, on CRRT for acute kidney injury (AKI) or fluid overload, were included. Patients with underlying kidney disease, on extracorporeal membrane oxygenation and non-survivors were excluded. FSS was collected at discharge (n = 527), 6 months (n = 387) and 12 months post-discharge (n = 344). The primary outcome was FSS at discharge and 6 months. Secondary outcomes included: new morbidity at discharge and 6 months; FSS at 12 months; and the impact of renal recovery on functional outcomes. Results A total of 527 patients had median FSS of 7 (6, 90) at hospital discharge. Thirty-nine percent (n = 204) had worse FSS. Eighteen percent (95/527) acquired a new morbidity at discharge. Predictors of FSS at discharge were baseline FSS {odds ratio (OR) 1.30 [95% confidence interval (CI) 1.11-1.52]}, weight [OR 0.99 (95% CI 0.98-0.9997)], comorbidities [OR 1.88 (95% CI 1.16-3.04)], mechanical ventilation [OR 1.72 (95% CI 1.04-2.85)] and sepsis on intensive care unit admission [OR 1.46 (95% CI 1.01-2.21)]. A total of 387 patients had median FSS score of 6 (6, 8) at 6 months. Ten percent (n = 39/387) acquired new morbidity at 6 months. The significant predictors of FSS at 6 months were FSS at discharge [OR 2.36 (95% CI 1.95-2.84)] and presence of comorbidities [OR 1.77 (95% CI 1.03-3.06)]. Conclusion This is the first large, multi-center study evaluating functional outcomes of children on CRRT. Persistent morbidity following discharge emphasizes the importance of comprehensive identification and multidisciplinary follow-up to optimize patient outcomes.