Patients with a body mass index (BMI) of ≥40 had more than double the risk of being put on a ventilator and a 26% higher risk of death compared with normal-weight COVID-19 patients. The mortality association was strongest in younger adults; patients aged ≤50 with severe obesity had a 36% higher risk of death compared with their normal-weight peers.

The BMI analysis from the AHA COVID-19 Cardiovascular Disease Registry was presented by Dr. Nicholas Hendren (University of Texas Southwestern, USA) [1].

Among the 7,606 patients in the registry as of July 22 for whom BMI data were available, the cohort was more likely to be obese compared with the National Health and Nutrition Examination Survey USA national registry, especially among patients aged ≤50 years. Black patients had higher rates of class-III obesity (≥40 kg/m2) compared with patients of other races and ethnicities.

Compared with those with normal weight, those with obesity had elevated risk for death or mechanical ventilation, with the risk rising with increasing obesity class: OR for class I obesity versus normal weight was 1.28 (95% CI 1.09-1.51), OR for class II obesity versus normal weight was 1.57 (95% CI 1.29-1.91), and OR for class III obesity versus normal weight was 1.8 (95% CI 1.47-2.2). He noted the endpoint was driven by mechanical ventilation, which was significantly higher in patients with overweight or any class of obesity compared with patients with normal weight (OR for overweight vs normal weight = 1.28; 95% CI 1.09-1.51; OR for class I obesity vs normal weight = 1.54; 95% CI 1.29-1.84; OR for class II obesity vs normal weight = 1.88; 95% CI 1.52-2.32; OR for class III obesity vs normal weight = 2.08; 95% CI 1.68-2.58).

He noted that class III obesity was associated with elevated risk for in-hospital mortality only in patients aged ≤50 years (HR 1.36; 95% CI 1.01-1.84). The hazards of poor outcomes related to obesity were most pronounced in patients aged ≤50 years (Pinteraction<0.05 for all primary endpoints). Significant BMI by age interactions were seen for all primary end points (P-interaction<0.05 for each), such that the association of BMI with death or mechanical ventilation was strongest in adults ≤50 years, intermediate in adults 51 to 70 years, and weakest in adults >70 years.

“We believe that clear public health messaging is needed for younger obese individuals who may underestimate their risk if they get COVID-19 and that severely obese individuals should be considered high risk for severe COVID-19 infection and may warrant prioritization for a COVID-19 vaccine,” Hendren said during the presentation.

  1. Hendren N, et al. Association of Body Mass Index With Death, Mechanical Ventilation and Cardiovascular Outcomes in COVID-19: Findings From the AHA COVID-19 Cardiovascular Disease Registry. LBS.08, Virtual AHA Scientific Sessions 2020, 13-17 Nov.
  2. Hendren N, et al. Association of Body Mass Index and Age With Morbidity and Mortality in Patients Hospitalized With COVID-19: Results From the American Heart Association COVID-19 Cardiovascular Disease Registry. Circulation. 2020;142:00-00.