Assessment of Early Renal Angina Index for Prediction of Subsequent Severe Acute Kidney Injury During Septic Shock in Children

Background: Acute kidney injury (AKI) is independently related to the adverse outcome of septic shock, but it lacks effective early predictors. Renal anginal index (RAI) was used to predict subsequent severe AKI (AKIs) in critically ill patients. The application of RAI in children with septic shock has not been reported. This study aims to evaluate the efficacy of early RAI in predicting subsequent AKIs within 3 days after PICU admission in children with septic shock by comparing with early fluid overload (FO) and early creatinine elevation.

Methods: Sixty-six children admitted to PICU aged 1 month to 16 years old, with septic shock from January 2016 to December 2019 were analyzed retrospectively. According to the 2012 Kidney Disease Improving Global outcomes (KDIGO) criteria, AKIs was defined by the KDIGO stage ≥2 within 3 days after PICU admission. Early RAI positive (RAI+) was defined as RAI ≥ 8 within 12 h of PICU admission. Any elevation of serum creatinine (SCr) over baseline within 12 h after PICU admission was denoted as "Early SCr > base". Early FO positive (FO+) was defined as FO > 10% within 24 h of PICU admission.

Results: Of 66 eligible cases, the ratio of early RAI+, early SCr > base, early FO+ was 57.57, 59.09 and 16.67% respectively. The incidence of AKIs in early RAI+ group (78.94%) was higher than that in early RAI- group (21.42%) (p = 0.04), and there was no significant difference compared with the early FO+ group (71.79%) and early SCr > base group (81.82%) (P > 0.05). After adjustment for confounders, early RAI+ was independently associated with the occurrence of AKIs within 3 days (OR 10.04, 95%CI 2.39-42.21, p < 0.01). The value of early RAI+ (AUC = 0.78) to identify patients at high risk of AKIs was superior to that of early SCr > base (AUC = 0.70) and early FO+ (AUC = 0.58). A combination of serum lactate with early RAI+ improved the predictive performance for assessing AKIs (AUC = 0.83).

Conclusions: Early RAI could be used as a more convenient and effective index to predict the risk of AKIs in children with septic shock within 3 days. Early RAI+ combined with serum lactate improved the predictive performance for assessing AKIs.