Risk Factors for Mortality in Critically Ill Children Requiring Renal Replacement Therapy.

Objectives: There is an increased mortality risk in critically ill children who require renal replacement therapy for acute kidney injury and fluid overload. Nevertheless, renal replacement therapy is essential in managing these patients. The objective of this study was to identify risk factors for mortality in critically ill children requiring renal replacement therapy. Design: Single-center, retrospective cohort analysis. Setting: Tertiary care children's hospital. Patients: All patients admitted to an ICU at Boston Children's Hospital from January 2009 to December 2017 who required any form of renal replacement therapy. Interventions: None. Measurements and Main Results: Four-hundred sixty-three patients required inpatient renal replacement therapy over the study period. Of these, there were 98 patients who had 99 unique encounters for renal replacement therapy that met eligibility criteria for analysis. The most common diagnoses were respiratory failure, stem cell transplant, and sepsis. The overall mortality was 55.6%. Nonsurvivors had a lower ICU admission weight compared with survivors (30.0 kg vs 44.0 kg; p = 0.037) and a higher degree of fluid accumulation at the time of renal replacement therapy initiation (17.1% vs 8.1%; p = 0.021). In multivariable logistic regression analysis, invasive mechanical ventilation (odds ratio, 7.22; 95% CI, 1.88-27.7), a longer duration of stage 3 acute kidney injury (odds ratio, 1.08; 95% CI, 1.02-1.15), and higher fluid balance in the 72 hours after initiating renal replacement therapy (odds ratio, 1.12; 95% CI, 1.05-1.20) were associated with an increased odds of mortality. Conclusions: Earlier renal replacement therapy initiation with respect to the development of severe acute kidney injury was associated with lower mortality in this cohort of critically ill children. Additionally, invasive mechanical ventilation at the time of renal replacement therapy initiation and a higher degree of fluid accumulation after initiating renal replacement therapy were associated with increased mortality.