Written by Jasna Trbojevic-Stankovic
Reviewed by Ronald Gansevoort
The coronavirus COVID-19 pandemic presented an unprecedented challenge to healthcare services worldwide in the previous months. The disease afflicts multiple organ systems and may also target kidney cells and cause acute kidney injury. On the other hand, patients with existing chronic kidney disease (CKD) are at a much higher risk for severe illness when infected. In response to the COVID-19 pandemic the European Renal Association- European Dialysis Transplantation Association (ERA-EDTA) established the European Renal Association COVID-19 Database (ERACODA) in March 2020 to investigate the clinical course, outcomes, and risk factors for mortality in kidney replacement patients with COVID-19. Related to this initiative and to spread the finest quality scientific knowledge and deliver the latest findings to the nephrology community, ERA-EDTA has organized a series of e-seminars on practical COVID-19 related aspects relevant to renal professionals. The second ERACODA seminar is dedicated to the COVID-related aspects of acute kidney injury (AKI) with professors Luuk Hilbrands and Ron Gansevoort as moderators, professors Nicholas Selby and Tobias Huber as presenters, and professors Eric Hoste and Bjorn Meijers as panelists.
The epidemiology of AKI in COVID-19: Clinical consequences
Presenter: Prof. Nicholas Selby (University of Nottingham, United Kingdom)
Panelist: Prof. Eric Hoste (Ghent University Hospital, Belgium)
Early reports at the onset of the COVID-19 pandemic indicated that rates of AKI in COVID-19 patients were negligible. One case series analysis even reported an incidence of 0%. However, later growing evidence demonstrated that AKI is notably prevalent, particularly among severe COVID-19 cases admitted to intensive care units (ICUs) (1, 2).
Still, the reported rates of AKI are remarkably variable. For instance, a systematic review of 20 studies that included more than 13,000 mostly hospitalized COVID-19 patients showed that the prevalence of AKI is 17%, with about 5% of all patients requiring the use of renal replacement therapy (RRT). The subgroup analysis, however, revealed substantial regional differences with AKI prevalence ranging between 19% and 57% in Europe and United States (3). Such differences likely resulted from different definitions of AKI and the populations studied. Another study, which defined AKI according to the KDIGO criteria, confirmed such assumptions and found that of 5,449 hospitalized COVID-19 patients, AKI developed in 36.6%. The peak stages of AKI were stage 1 in 46.5%, stage 2 in 22.4%, and stage 3 in 31.1% (4). Several reports also indicate that between 61% and 76% of COVID-19 patients admitted to the ICU develop AKI and that between 26% and 45% of them require RRT (4-6). COVID-19-positive patients are twice as likely to develop AKI compared to the COVID-19–negative hospitalized patients (7). Another study reported that about 75% of patients with COVID-19 pneumonia had renal involvement on admissions: 65.8% presented with proteinuria, 41.7% with hematuria, and 4.7% with AKI (8).
Independent risk factors for AKI include older age, diabetes mellitus, cardiovascular disease, black race, hypertension, and need for mechanical ventilation and vasopressor medications. As shown in Figure 1, most cases develop AKI early in the course, usually arriving with AKI or developing it within 24 hours of admission. Then, the second peak occurs typically after eight or more days due to clinical deterioration (e.g. secondary sepsis) or around the time of mechanical ventilation (4).