Critically ill children and neonates admitted to Intensive Care are at high risk of developing acute kidney injury (AKI) and do so early in the course of their illness. AKI is associated with increased duration of stay in intensive care, short and long term renal impairment, increased mortality, and increased hospital costs. AKI is currently diagnosed when serum creatinine (SCr) levels rise, however there may be a 48 hour delay between renal insult and detectable increase in SCr levels. This can delay diagnosis of AKI and hence potential intervention to mitigate renal damage. New AKI biomarkers can aid early diagnosis in patient groups where there is a timed potential renal insult (eg: cardiac surgery), however their utility has not been assessed in a mixed patient cohort.
We conducted a pilot study for all admissions to PICU at the Royal Manchester Children’s Hospital over a 6 month period to identify risk factors for developing AKI and to measure the correlations between SCr and new AKI biomarkers. We defined AKI as eGFR <100 ml/min/1.73m2 (Schwartz formula calculation). We collected urine and plasma from 50 children (age 16 days-15 years, 46% male) for the measurement of Cystatin C, KIM-1 and NGAL. We observed a 30% incidence of AKI in this cohort and age <12 months was a significant risk factor for AKI. New biomarker analysis correlated with SCr in 93% of cases and preceeded the rise by 24–48 hours in 20% of patients. The utility of new biomarkers for early detection was limited by the presence of AKI at study entry.
This investigation demonstrates feasibility of new AKI biomarker testing and in combination with risk stratification, could identify children who need to be protected from secondary renal injury during their inpatient admission.