11 Impact of BMI on Outcomes in Patients Hospitalized for COVID-19

Study Objectives: Obesity is a common problem, affecting over 40% of U.S. adults. It is a risk factor for chronic diseases such as type 2 diabetes, heart disease, and some cancers. There is some evidence it may also be associated with increased morbidity for COVID-19–associated illness. The authors sought to quantify the relationship between BMI and mortality after COVID-19. Methods: This was an observational retrospective cohort study from 178 hospitals from a large health system across the United States. Patients who presented to the hospital with confirmed COVID-19 between January 1st, 2020, and September 1st, 2020 were evaluated for outcomes during hospitalization, including disease severity by level of care, intensive care unit admission, hospital length of stay, and in-hospital death. Disease severity was classified as moderate, severe or critical. Moderate disease was defined as highest level of care being the medical floor;critical disease was defined as highest level of care being the intensive care unit (ICU) and requiring mechanical ventilation and/or vasopressor support;and severe disease was defined as highest level of care being ICU but not meeting criteria for critical disease. Results: There were 45,340 patients in the cohort. The median age was 63 years (IQR 49-75). Forty eight percent of the cohort was female. Median overall BMI was 29.3 (IQR 25.1 to 34.7). In men median BMI was 28.6 (IQR 25.0 to33.3). In women the median BMI was 30.1 (IQR 25.4 to 36.2). Men had a significantly lower BMI when compared to women (P<0.001). Age was inversely correlated to BMI (P<0.001, 95% CI -0.130 to -0.130). The majority of the cohort (57%) had moderate disease, with 29% having severe disease and 14% have critical diseases. The overall mortality was 15%. The overall hospital median length of stay (LOS) was 5 days (IQR 3-11). Patients with higher BMI were significantly more likely to require mechanical ventilation and require pressor support (P<0.0001, 95% CI 0.0013 to 0.0021) [Figure 1]. Patients with higher BMI were also significantly more likely to die (P<0.001, OR 1.031, 95% CI 1.03-1.04). This association held true even when analyzed in a multivariable regression model controlled for age and sex (p=0.0131). The hospital length of stay was inversely correlated to the BMI. Bivariate analysis demonstrated that the average length-of-stay could be approximated as 9.1 days -0.03*BMI. Presumably, this is because at higher BMIs there is higher mortality resulting in shorter LOS. Conclusion: Patients with elevated BMI were significantly more likely to have highest disease severity, higher mortality and shorter length-of-stay in this large national cohort of patients hospitalized for COVID-19. [Formula presented]