Association between BMI and risk of AKI in hospitalized patients with COVID-19

Background: AKI in hospitalized patients with COVID-19 is a common adverse complication. Our aim was to investigate risk factors associated with AKI and whether AKI in this setting is independently associated with in-hospital mortality at 30 days. Methods: All adult patients admitted with a positive SARS-CoV-2 PCR between 3 /2021 to 1/2021 to nineteen hospitals who had a COVID-associated billing diagnosis and no history of ESKD or kidney transplant were included. AKI was defined according to the Kidney Disease Improving Global Outcomes guidelines. Risk factors associated with AKI were evaluated with univariable and multivariable logistic regression, and mortality was evaluated using Kaplan-Meier and Cox Proportional Hazards models. Results: The study cohort included 9,681 patients, of which 3,666 (38%) met criteria for AKI. Compared with patients without AKI, patients with AKI were older [mean (SD) age 67 (16) vs. 60 (18) years], more likely to be male (58% vs. 47%), and more likely to be black (21% vs. 15%). Patients with AKI were also more likely to have diabetes mellitus (52% vs. 32%), hypertension (78% vs. 57%), CKD (55% vs. 17%), and coronary artery disease (20% vs. 11%). Patients with AKI were also more likely to be on ACEi/ ARB on admission (51% vs. 37%), require mechanical ventilation (21% vs. 3.2%) or have higher WBC, hs-CRP, ferritin, D-dimer, and cardiac troponin). P-values were <0.001 for all of the aforementioned comparisons. Risk factors significantly associated with AKI in the multivariable model included age, sex, race, hypertension, CKD, diabetes, ACEi or ARB on admission, mechanical ventilation, WBC on admission, hs-CRP, ferritin, d dimer and troponin. Death occurred more frequently in patients with AKI (22.1%;n=811) than in those without (3%;n=178). Patient with AKI had higher mortality risk as compared to those without AKI, hazard ratio (HR) 3.08 (95% CI 2.56-3.71), that remained significant even after controlling for all variables associated with AKI, such as age, sex, race, comorbidities, inflammatory biomarkers, elevated troponin, and COVID-related treatments, HR 1.64 (95% CI 1.34-2.01). Conclusions: Patients with COVID-19 who develop AKI have a higher mortality. We found risk factors associated with AKI in the setting of COVID, and that the increased mortality risk associated with AKI in COVID-19 is independent of these factors.