Timing of continuous renal replacement therapy and mortality in critically ill children*.

OBJECTIVES Acute kidney injury and fluid overload frequently necessitate initiation of continuous renal replacement therapy in critically ill patients admitted to the ICU. In this study, our primary objective was to determine the effect of timing of initiation of continuous renal replacement therapy on ICU mortality in children requiring renal support for management of acute kidney injury and/or fluid overload. DESIGN Retrospective cohort study. SETTING Tertiary level, multidisciplinary PICU. PATIENTS Children who received continuous renal replacement therapy for management of acute kidney injury and/or fluid overload from January 2000 through July 2009 were included in the study. Patients requiring extracorporeal life support and patients initiated on continuous renal replacement therapy for indications other than acute kidney injury and/or fluid overload were excluded. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Timing of initiation was defined chronologically as time from ICU admission to continuous renal replacement therapy initiation. Three hundred eighty treatments were performed during the study period, of which 190 were eligible and included in the study. Overall ICU mortality was 47% among the study population. Median timing of initiation was higher among nonsurvivors compared with survivors (3.4 vs 2.0 d, p = 0.001). Multivariable logistic regression analysis identified timing of initiation as an independent predictor of mortality with an adjusted odds ratio of 1.05 (95% CI, 1.01, 1.11). Fluid overload, indication for continuous renal replacement therapy initiation, severity of illness at ICU admission, and active oncologic diagnosis were the other independent predictors of mortality that were identified in the final regression model. In the survival analysis, late initiators (> 5 d) had higher mortality than early initiators (≤ 5 d) with a hazard ratio of 1.56 (95% CI, 1.02, 2.37). CONCLUSIONS Earlier initiation of continuous renal replacement therapy was associated with lower mortality in this cohort of critically ill children. Future studies should focus on early identification of such children who may benefit from early continuous renal replacement therapy initiation.