BMI and Risk for Severe COVID-19 Among Veterans Health Administration Patients

Abstract

Objective: The purpose of this study was to assess associations between BMI and severe coronavirus disease 2019 (COVID-19) outcomes: hospitalization, intensive care unit (ICU) admission, and mortality. A secondary aim was to investigate whether associations varied by age. Methods: The cohort comprised patients in the Veterans Health Administration (VHA) who tested positive for COVID-19 (N = 9,347). For each outcome, we fit piecewise logistic regression models with restricted cubic splines (knots at BMI of 23, 30, and 39), adjusting for age, sex, comorbidities, VHA nursing home residence, and race/ethnicity. Supplemental analyses included age-by-BMI interaction terms (α = 0.05). Results: We found evidence of a nonlinear J-curve association between BMI and likelihood of hospitalization and mortality. BMI was associated with increased odds for hospitalization, ICU admission, and mortality among patients with BMI 30 to 39 but decreased odds of hospitalization and mortality for patients with BMI 23 to 30. Patients under age 75 with BMI between 30 and 39 had increased odds for mortality with increasing BMI. Conclusions: Odds for severe outcomes with COVID-19 infection increased with increasing BMI for people with, but not without, obesity. This nonlinear relationship should be tested in future research. COVID-19 public health messages in VHA, and broadly, should incorporate information about risks associated with all classes of obesity, particularly for those under age 75.