Is BMI Associated with COVID-19 Severity? A Retrospective Observational Study

Background Coronavirus-19 disease (COVID-19) is an infection with high morbidity and mortality. Obesity and low body mass index (BMI) have both been linked to severe COVID-19, but recent studies have failed to confirm these associations. Objectives The aim of this study was to examine the relationship between BMI and disease progression in hospitalised patients with COVID-19. Methods We performed a monocentric, retrospective observational study at the Fondazione Policlinico Gemelli in Rome. We enrolled 1544 (977 men) patients who presented to the emergency department with a positive COVID-19 test between January and December 2021. We divided patients into five classes based on BMI. Demographic, clinical, laboratory, and radiological data were collected for all patients. Results Of the 1544 patients, 1297 recovered after hospitalization, whereas 247 (16%) died. Of those who died, 16/247 (6.5%) had a BMI below18.5 kg/m(2), 72/247 (29%) had a BMI between 18.5 and 24.99 kg/m(2), 103/247 (42%) had a BMI between 25 and 29.99 kg/m(2), 36/247 (15%) had a BMI between 30 and 35 kg/m(2), and 20/247 (8%) had a BMI above 35 kg/m(2). After adjusting the results for age, sex, and concomitant diseases using multivariate logistic regression, we found a significantly increased risk of intensive care unit (ICU) admission in severely obese patients (BMI > 35) compared to normal weight patients (BMI: 18.5-24.99) (p > 0.001). Mortality was not associated with BMI. Conclusion We confirm that severe obesity is a risk factor for ICU admission in patients with COVID-19. No association was found between BMI and mortality.