IMPACT OF COVID-19 PANDEMIC ON IN-HOSPITAL ACUTE KIDNEY INJURY EPIDEMIOLOGY AND OUTCOMES: A RETROSPECTIVE COHORT STUDY

Background and Aims: Acute kidney injury (AKI) is a common complication in patients affected by Coronavirus disease-19 (COVID-19) and its development is associated with high mortality [1]. However, it is also clear that the COVID-19 pandemic has effects also on the management of diseases, not directly related to COVID-19 [2]. In this study, we investigated the impact of the COVID-19 pandemic on general intrahospital AKI incidence and outcomes. Method: We performed a retrospective cohort study comparing data on AKI epidemiology and outcomes of patients hospitalized from January 2016 to December 2019 (Pre-COVID-19 period) and from January to December 2020 (COVID-19 period, including both SARS-CoV-2 negative and positive patients). AKI was defined and classified evaluating the kinetics of intra-hospital creatinine (comparing the peak to the minimum serum creatinine level, considered as the basal value) [3]. The prevalence of chronic kidney disease (CKD) (i.e. eGFR <60 mL/min) was calculated in patients with previous creatinine values available. Patients with CKD stage 4-5 (i.e. eGFR<30 ml/min per 1.73 m2) and with a length of hospital stay> 30 days were excluded Results: 51,681 patients during the Pre-COVID-19 period and 10,062 during the COVID-19 period (9,026 SARS- CoV-2 negative and 1,036 SARS-CoV-2 positive patients) were analyzed. Patients admitted in the COVID-19 period were significantly older, with a higher prevalence of males and reduced prevalence of chronic conditions. In-hospital AKI incidence was 31.7% during the COVID-19 period (30.5% in SARS- CoV-2 negative patients and 42.2% in SARS-CoV-2 positive ones) as compared to 25.9% during the pre- COVID-19 period (p<0.0001) (Figure 1). Similarly, the COVID-19 period showed an increase in AKI stage 2-3 incidence both for AKI on CKD and for “de novo AKI”. In multivariate analysis, demographic characteristics, length of hospital stay, ICU admission, main comorbidities, basal sCr, admission period (Pre-COVID-19 or COVID-19) and SARS-CoV-2 infection were significantly associated with the risk of AKI. In particular, the admission in the COVID-19 period increased the risk of AKI (OR 1.18, IC 1.12- 2.25) regardless of SARS-CoV2 infection. Moreover, we found that in the COVID-19 period, there was an increased number of patients admitted to ICU, accompanied by a significant increase in the length of hospital stay and intrahospital mortality. At the multivariate analysis, development of AKI, admission in the COVID-19 period and active SARS-CoV-2 infection remained significantly and independently associated with mortality risk (Figure 2). Conclusion: Overall, we found that AKI was more common and severe in the COVID-19 period, regardless of SARS- CoV2 infection, when compared with patients admitted to the same hospital during the four years before the pandemic. So, we provide evidence that the COVID-19 pandemic has changed general in-hospital AKI epidemiology. These findings call attention to the need to adapt the resources dedicated to the prevention and management of the intrahospital AKI in response to health emergencies.