The Association Between BMI and Inpatient Mortality Outcomes in Older Adults With COVID-19

Background and aim Coronavirus disease 2019 (COVID-19) is known to cause a broad spectrum of illnesses. There is evidence that obesity-related conditions may increase the severity of COVID-19 disease, especially in those below the age of 60. However, there has been limited research on mortality rate based on body mass index (BMI) in the older adult population, defined as age over 65. The objective of this study was to characterize outcomes in older adults infected with COVID-19 based on BMI. Study design and methods It is a single-center retrospective cohort study of older adults with COVID-19 infection. The primary outcome was hospital mortality. Secondary outcomes assessed were oxygen requirements, need for mechanical ventilation, duration of mechanical ventilation, and hospital length of stay. Data were analyzed with the Student's t-test, Fisher's exact test, and multiple logistic regression analyses as appropriate. Results A total of 290 patients were included in this study. The mean age was 77.6 years. The median BMI was >30 kg/m2. The primary outcome of hospital mortality occurred in 49.7% of patients. BMI was not found to be a predictor of mortality. Age 75-79 and age ≥ 85 were associated with an increased risk of mortality (OR: 2.58; 95% CI: 1.15 - 5.79; OR: 3.17; 95% CI: 1.35 - 7.44, respectively). Patients with a BMI < 18.5, BMI 18.5 - 25, and age ≥ 85 were less likely to require mechanical ventilation (OR: 0.06; 95% CI: 0.00 - 0.83; OR:0.11; 95% CI: 0.02 - 0.64 and OR:0.28; 95% CI: 0.09 - 0.92, respectively). Past medical history was not associated with mortality. Conclusion In a cohort of older adults with COVID-19 disease, BMI was not an independent predictor of in-hospital mortality. Patients with BMI ≤ 25 and age ≥ 85 years were less likely to require mechanical ventilation.