Acute kidney injury in children hospitalised for febrile urinary tract infection

Aim: To determine (i) prevalence and the risk factors for acute kidney injury (AKI) in children hospitalised for febrile urinary tract infection (fUTI) and (ii) role of AKI as indicator of an underlying VUR. AKI, in fact, is favoured by a reduced nephron mass, often associated to VUR. Methods: This retrospective Italian multicentre study enrolled children aged 18 years or younger (median age = 0.5 years) discharged with a primary diagnosis of fUTI. AKI was defined using Kidney Disease/Improving Global Outcomes serum creatinine criteria. Results: Of 849 children hospitalised for fUTI (44.2% females, median age 0.5 years; IQR = 1.8), 124 (14.6%) developed AKI. AKI prevalence rose to 30% in the presence of underlying congenital anomalies of the kidney and urinary tract (CAKUT). The strongest AKI predictors were presence of CAKUT (OR = 7.5; 95%CI: 3.8–15.2; p = 9.4e-09) and neutrophils levels (OR = 1.13; 95%CI: 1.08–1.2; p = 6.8e-07). At multiple logistic regression analysis, AKI during fUTI episode was a significant indicator of VUR (OR = 3.4; 95%CI: 1.7–6.9; p = 0.001) despite correction for the diagnostic covariates usually used to assess the risk of VUR after the first fUTI episode. Moreover, AKI showed the best positive likelihood ratio, positive predictive value, negative predictive value and specificity for VUR. Conclusion: AKI occurs in 14.6% of children hospitalised for fUTI and is a significant indicator of VUR.