Retrospective evaluation of acute kidney injury in paediatric COVID-19 patients: a tertiary referral hospital experience

Background Coronavirus disease 2019 (COVID-19) has been recognised as a risk factor for acute kidney injury (AKI). Our aim was to investigate the risk factors contributing to hospitalised and outpatient paediatric COVID-19-associated AKI. Methods A retrospective observational study was conducted on patients aged 1 month to 18 years with diagnosed COVID-19-associated AKI applied to a tertiary paediatric referral hospital between March 1, 2020 and March 1, 2022. Results A total of 6683 patients were evaluated and 486 patients were included in the study. Acute kidney injury was observed in 3.7% of outpatients and 23.9% of hospitalised patients. Multivariate logistic regression analysis showed that, on admission, a history of contact with a COVID-19 positive person (p < 0.001), age below 12 months (p = 0.004), presence of comorbidities (p < 0.001), abdominal pain (p = 0.008), anorexia (p = 0.003), dyspnoea (p = 0.005), higher lactate dehydrogenase values (p = 0.004), neutrophilia (p < 0.001), higher neutrophil-to-lymphocyte ratio (NLR) (p = 0.003), higher white blood cell counts (p = 0.006), elevated C-reactive protein (CRP) levels (p = 0.002), anaemia (p = 0.015), hypoalbuminaemia (p < 0.001), hyperglycaemia (p = 0.006), and presence of proteinuria (p = 0.003) were independent predictors of AKI. Higher rates of hospitalisation (p < 0.001) and admission to the paediatric intensive care unit (PICU) (p < 0.001), longer length of hospitalisation (p < 0.001), and greater need for mechanical ventilation (p < 0.001) were associated with AKI. Conclusions This study reveals that not only hospitalised children, but also paediatric patients are at risk for AKI. The presence of comorbidities, abdominal pain, anorexia, dyspnoea, anaemia, inflammation, hypoalbuminaemia, proteinuria and history of contact with a COVID-19 positive person were the main risk factors for AKI. COVID-19-associated AKI was associated with worse outcomes.