The effect of obesity on in-hospital mortality among patients with COVID-19 receiving corticosteroids

Background and aims: Obesity has been reported to be one of the most frequent comorbidities in COVID-19 patients and associated with higher rates of in-hospital mortality compared to non-obese patients. Acute kidney injury (AKI) is also known to be a complication associated with obesity in critically-ill COVID-19 patients. We aimed to investigate whether obesity was associated with increased risk of in-hospital mortality and AKI among patients with COVID-19 treated with corticosteroids. Methods: We utilized 9965 hospitalized COVID-19 patient data and divided patients who were treated with corticosteroids into 6 groups by body mass index (BMI) (less than 18.5, 18.5–25, 25–30, 30–35, 35–40, 40 kg/m² or greater). The association between BMI and in-hospital mortality and between BMI and incidence rate of AKI during admission among COVID-19 patients receiving corticosteroids were retrospectively investigated. Results: There were 4587 study participants receiving corticosteroids (mean age 66.5 ± 15.5 years, men 56.6%, mean BMI 29.0 ± 7.2 kg/m²). The smooth spline curve suggested a J-shape association between BMI and in-hospital mortality. Patients with BMI above 40 kg/m² exhibited a higher in-hospital mortality and higher incidence rate of AKI during admission compared to patients with BMI between 25 and 30 kg/m². The differences in in-hospital mortality and the rate of AKI were larger among patients with severe COVID-19. Conclusions: Class III obesity was associated with high in-hospital mortality and AKI in patients with COVID-19 treated by corticosteroids. Clinicians must stay vigilant on the impact of class III obesity and development of AKI to disease trajectory of COVID-19 patients.