Acute kidney injury (AKI) among critically ill children and young adults is common and is associated with higher mortality risk and other poor outcomes, according to researchers.
In a large, prospective, multinational study that included 4683 patients aged 3 months to 25 years (median age 5.5 years) admitted to intensive care units (ICUs), AKI developed in 1261 (26.9%) patients and severe AKI developed in 543 (11.6%). Severe AKI was associated with 77% higher odds of death by day 28 after adjustment for 16 covariates, investigators led by Stuart L. Goldstein, MD, of the Center for Acute Care Nephrology, Cincinnati Children’s Hospital Medical Center in Cincinnati, Ohio, reported online in The New England Journal of Medicine.
Sixty (11%) of the 543 patients with severe AKI died compared with 105 (2.5%) of the 4140 patients without severe AKI. In addition, severe AKI was associated with increased use of renal-replacement therapy and mechanical ventilation and longer ICU stays.
Assessment of AKI based on plasma creatinine level alone failed to identified AKI in 67.2% of patients with low urine output, and the mortality rate was higher among patients with low urine output than those with normal urine output (7.8% vs 2.9%), the investigators reported.
Dr Goldstein’s team used the Kidney Disease: Improving Global Outcomes criteria to define AKI. The defined severe AKI as stage 2 or 3 AKI (plasma creatinine level 2 or more times the baseline level or urine output less than 0.5 mL per kilogram of body weight per hour for at least 12 hours) and was assessed for the first 7 days of intensive care.
Further, the study showed that the daily prevalence of AKI increased progressively from 14.5% to 20.4% over a period of 7 days. Patients with stage 1 AKI on day 1 were significantly more likely to experience progression to stage 2 or 3 by day 7 than patients without AKI on day 1 (14.1% vs 2.9%), Dr Goldstein and his colleagues reported.
The researchers said their study results provide informative comparisons with those of a recent multicenter study of adults: the Acute Kidney Injury–Epidemiologic Prospective Investigation (AKI-EPI) study. Although the rates of overall and severe AKI (57.3% and 38.9%, respectively) were higher in the adult study than the corresponding rates in the pediatric study, the associations between AKI and mortality and morbidity are similar. “We speculate that the relatively lower rates of acute kidney injury observed in our study represent greater renal reserve in children,” Dr Goldstein’s team wrote.
Study strengths included a large, multicenter cohort that enabled a robust evaluation of relationships between exposure and outcome, a prespecified protocol, operational definitions, and an analysis plan and enumerated complete standardized diagnostic criteria for AKI, the investigators stated.
They also acknowledged study limitations. The observational design of the study precluded making statements regarding causal relationships among AKI, exposures, and outcomes observed. In addition, the investigators did not assess for the potential effect of the specific cause of AKI on patient outcomes.