Comparison of diagnostic criteria for acute kidney injury in critically ill children

Abstract

Objective: The kidney disease: improving global outcome (KDIGO) and pediatric reference change value optimized for acute kidney injury (pROCK) criteria were used to evaluate the incidence, stages and mortality of acute kidney injury (AKI). The differences between the 2 criteria were compared for exploring the value of pROCK criteria in diagnosing pediatric AKI and predicting adverse outcomes. Methods: In the multicenter prospective clinical cohort study, we collected general data and clinical data such as serum creatinine values from 1 120 children admitted to 4 PICUs of Children's Hospital of Soochow University, Children's Hospital of Fudan University, Anhui Provincial Children's Hospital, and Xuzhou Children's Hospital from September 2019 to February 2021. AKI was defined and staged according to the KDIGO and pROCK criteria. The incidence of AKI, the consistency of AKI definite diagnosis and stages, and the mortality in PICU were compared between the 2 groups. The chi-square test or Fisher's exact test was applied for comparison between 2 groups. The Cohen's Kappa and Weighted Kappa analyses were used for evaluating diagnostic consistency. The Cox regression analysis was used to evaluate the correlation between AKI and mortality. Results: A total of 1 120 critically ill children were included, with an age of 33 (10, 84) months. There are 668 boys and 452 girls. The incidence of AKI defined by the KDIGO guideline was higher than that defined by pROCK criteria (27.2%(305/1 120), 14.7%(165/1 120), χ2=52.78, P<0.001). The concordance rates of the 2 criteria for the diagnosis of AKI and AKI staging were 87.0% (κ=0.62) and 79.7% (κ=0.58), respectively. Totally 63 infants with AKI stage 1 defined by the KDIGO guideline were redefined as non-AKI by following the pROCK criteria. The PICU mortality rate of these infants was similar to patients without AKI defined by KDIGO guideline(P=0.761). After adjusting for confounders, AKI defined by KDIGO or pROCK criteria was an independent risk factor of death in PICU (AHR=2.04, 2.73,95%CI 1.27-3.29, 1.74-4.28, both P<0.01), and the risk of death was higher when using the pROCK compared with the KDIGO criteria. As for the KDIGO criteria, mild AKI was not associated with the mortality in PICU (P=0.702), while severe AKI was associated with increased mortality (P<0.001). As for the pROCK criteria, both mild and severe AKI were risk factors of PICU death in children (HR=3.51, 6.70, 95%CI 1.94-6.34, 4.30-10.44, both P<0.001). In addition, The AKI severity was positively associated with the mortality. Conclusions: The AKI incidence and staging varied depending on the used diagnostic criteria. The KDIGO definition is more sensitive, while the pROCK-defined AKI is more strongly associated with high mortality rate.