Association of body mass index with COVID-19 related in-hospital death

Background: Patients with extreme body mass indices (BMI) could have an increased risk of death while hospitalized for COVID-19. Methods: The database of the International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC) was used to assess the time to in-hospital death with competing-risks regression by sex and between the categories of BMI. Results: Data from 12,137 patients (age 60.0 ± 16.2 years, 59% males, BMI 29.4 ± 6.9 kg/m2 ) of 48 countries were available. By univariate analysis, underweight patients had a higher risk of mortality than the other patients (sub-hazard ratio (SHR) 1.75 [1.44e2.14]). Mortality was lower in normal (SHR 0.69 [0.58e0.85]), overweight (SHR 0.53 [0.43e0.65]) and obese (SHR 0.55 [0.44e0.67]) than in underweight patients. Multivariable analysis (adjusted for age, chronic pulmonary disease, malignant neoplasia, type 2 diabetes) confirmed that in-hospital mortality of underweight patients was higher than overweight patients (females: SHR 0.63 [0.45e0.88] and males: 0.69 [0.51e0.94]). Conclusion: Even though these findings do not imply changes in the medical care of hospitalized patients, they support the use of BMI category for the stratification of patients enrolled in interventional studies where mortality is recorded as an outcome.