Long-term risk of CKD in children surviving episodes of acute kidney injury in the intensive care unit: a prospective cohort study

Background: The development of standardized acute kidney injury (AKI) definitions has allowed for a better understanding of AKI epidemiology, but the long-term renal outcomes of AKI in the pediatric critical care setting have not been well established. This study was designed to: (1) determine the incidence of chronic kidney disease (CKD) in children 1-3 years after an episode of AKI at a tertiary-care pediatric intensive care unit (ICU), (2) identify the proportion of patients at risk of CKD, and (3) compare ICU admission characteristics in those with and without CKD.

Design: Prospective cohort study.

Setting & participants: Patients admitted to the British Columbia Children's Hospital pediatric ICU from 2006-2008 with AKI, as defined by AKI Network (AKIN) criteria. Surviving patients, most with short-term recovery from their AKI, were assessed at 1, 2, or 3 years after AKI.

Predictors: Severity of AKI as defined by AKIN and several ICU admission characteristics, including demographics, diagnosis, severity of illness, and ventilation data.

Outcomes & measurements: CKD was defined as the presence of albuminuria and/or glomerular filtration rate (GFR) < 60 mL/min/1.73 m2. Being at risk of CKD was defined as having a mildly decreased GFR (60-90 mL/min/1.73 m2), hypertension, and/or hyperfiltration (GFR ≥ 150 mL/min/1.73 m2).

Results: The proportion of patients with AKI stages 1, 2, and 3 were 44 of 126 (35%), 47 of 126 (37%), and 35 of 126 (28%), respectively. The number of patients with CKD 1-3 years after AKI was 13 of 126 (10.3% overall; 2 of 44 [4.5%] with stage 1, 5 of 47 [10.6%] with stage 2, and 6 of 35 [17.1%] with stage 3; P = 0.2). In addition, 59 of 126 (46.8%) patients were identified as being at risk of CKD.

Limitations: Several patients identified with AKI were lost to follow-up, with the potential of underestimating the incidence of CKD.

Conclusions: In tertiary-care pediatric ICU patients, ∼10% develop CKD 1-3 years after AKI. The burden of CKD in this population may be higher with further follow-up because several patients were identified as being at risk of CKD. Regardless of the severity of AKI, all pediatric ICU patients should be monitored regularly for long-term kidney damage.