Trajectory of AKI in hospitalized pediatric patients—impact of duration and repeat events

Abstract

Peak severity of acute kidney injury (AKI) is associated with mortality in hospitalized pediatric patients. Other factors associated with AKI, such as number of AKI events, severity of AKI events, and time spent in AKI may also have associations with mortality. Characterization of these events could help to evaluate patient outcomes. Pediatric inpatients (1) AKI, AKI severity (maximum KDIGO stage), and total number of AKI events. AKI duration as percent admission days in a KDIGO stage and AKI percent velocity were determined. Kaplan-Meier analysis was performed for time to 30 day survival by AKI characterization. A mixed effects logistic regression model with mortality as the dependent variable and nested in patients was developed incorporating patient variables and AKI characterizations. A total of 184,297 inpatient encounters met study criteria (male 51.7%, Age 7.8 years (IQR 2.5, 13.8), mortality 0.56%). Hospital length of stay was 1.9 days (IQR 0.37, 4.8 days), 15.4% had an intensive care unit admission and 12.2% underwent mechanical ventilation. AKI occurred in 5.6% (n = 10,246) of admissions (Stage I = 4.5% (n = 8,310), Stage II = 1.3% (n = 2,363), Stage III=0.77% (n = 1,423)) and repeat AKI events occurred in 1.92% (n = 3,558). AKI was associated with mortality (OR 6.0, 95% CI 4.8, 7.6, p < 0.001) and increasing severity (KDIGO maximum stage) was associated with increased mortality. Multiple AKI events were also associated with mortality (p < 0.001),. Duration of AKI was associated with mortality (p < 0.001) but AKI velocity was not (p > 0.05). AKI occurs in 5.6% of the pediatric inpatient population and multiple AKI events occur in ∼30% of these patients. Maximum KDIGO stage is most strongly associated with mortality. Multiple AKI events and AKI duration should also be considered when evaluating patient outcomes.