The risk for invasive mechanical ventilation, hospitalization and death in those with COVID-19 increased with BMI, according to research published in MMWR.

“The findings in this report highlight a dose-response relationship between higher BMI and severe COVID-19–associated illness and underscore the need for progressively intensive illness management as obesity severity increases,” LyudmylaKompaniyets, PhD, a postdoctoral research fellow at the CDC, and colleagues wrote. “Continued strategies are needed to ensure community access to nutrition and physical activity opportunities that promote and support a healthy BMI.”

Kompaniyets and colleagues evaluated associations between BMI and risk for severe COVID-19 with data from the Premier Healthcare Database Special COVID-19 Release (PHD-SR). The database included information from 238 U.S. hospitals on patients’ height and weight.

Within the study, researchers categorized patients as underweight if they had a BMI below 18.5 kg/m², healthy weight if they had a BMI of 18.5 kg/m²to24.9 kg/m² and overweight if they had a BMI of 25 kg/m²to29.9 kg/m². They further categorized obesity as having a BMI of 30 kg/m²to34.9 kg/m², 35 kg/m²to39.9 kg/m², 40 kg/m²to44.9 kg/m² or 45 kg/m²or greater.

Among 3,242,659 adult patients who received ED or inpatient care at the included institutions, 148,494 were diagnosed with COVID-19. Of these patients, 28.3% were overweight and 50.8% were obese.

Kompaniyets and colleagues determined that obesity was a risk factor for hospitalization and death. They found that, compared with those who had a healthy weight, the risk for COVID-19 hospitalization increased among patients with obesity, ranging from those with a BMI of 30 kg/m² to 34.9 kg/m² (aRR = 1.07; 95% CI, 1.05–1.09) to those with a BMI 45 kg/m² or greater (aRR = 1.33; 95% CI, 1.30-1.37).

They also found that the risk for death among patients with obesity increased from those who had a BMI of 30 kg/m²to34.9 kg/m² (aRR = 1.08; 95% CI, 1.02-1.14) to those with a BMI of 45 kg/m² or greater (aRR = 1.61; 95% CI, 1.47-1.76), compared with patients who had healthy weight.

The researchers determined that the risk for ICU admission increased from those with a BMI of 40 kg/m²to44.9 kg/m² (aRR = 1.06 ;95% CI, 1.03-1.1) to those with a BMI of 45 kg/m² or greater (aRR = 1.16; 95% CI, 1.11-1.20) compared with patients with healthy weight.

Compared with those with healthy weight, the risk for invasive mechanical ventilation increased from patients who were overweight (aRR = 1.12; 95% CI, 1.05-1.19) to those with a BMI of 45 kg/m² or greater (aRR = 2.08; 95% CI, 1.89-2.29).

“Preventing COVID-19 in adults with higher BMIs and their close contacts remains important and includes multifaceted protection measures such as masking, as well as continued vaccine prioritization and outreach for this population,” Kompaniyets and colleagues wrote.