The incidence, risk factors and impact of acute kidney injury in hospitalized patients due to COVID-19.

The incidence of acute kidney injury (AKI) in hospitalized patients with COVID-19 is variable, being associated with worse outcomes. The objectives of the study were to evaluate the incidence, risk factors (considering demographic characteristics, comorbidities, initial clinical presentation and associated complications) and impact of AKI in subjects hospitalized for COVID-19 in two third-level hospitals in Córdoba, Argentina. A retrospective cohort study was conducted. We included 448 adults who were consecutively hospitalized for COVID-19 between March 3 and October 31, 2020 and were followed throughout the hospitalization. The incidence of AKI was 19% (n = 85; stage I = 43, stage II = 17, and stage III = 25, 18 required renal replacement therapy). In the multivariate analysis, the variables that were independently associated with AKI were: age (for every 10 years, adjusted odd ratio [95%CI] = 1.30 [1.04-1.63], p = 0.022), history of chronic kidney disease -CKD- (9.92 [4.52-21.77], p < 0.001), blood neutrophil count at admission -BNCA- (for every increase of 1000 BNCA, 1.09 [1.01-1.18], p = 0.037) and requirement for mechanical ventilation -MV- (6.69 [2.24-19.90], p = 0.001). AKI was associated with longer hospitalization, higher admission (63.5 vs. 29.7%; p < 0.001) and longer stay in the intensive care unit, a positive association with respiratory bacterial superinfection, sepsis, respiratory distress syndrome, MV requirement and mortality (mortality without AK I = 12.4% vs with AKI = 47.1%; stage I = 26%, stage II = 41% and stage III = 88%; p < 0.001). AKI was independently associated with higher mortality (3.32 [1.6-6.9], p = 0.001). In conclusion, the incidence of AKI in adults hospitalized for COVID-19 was 19% and had a clear impact on morbidity and mortality. The independent risk factors for AKI were: Age, CKD, BNCA and MV.