Obesity IS Considered a High-Risk Condition for Severe COVID-19
Obesity is definitively recognized as a critical independent risk factor for severe COVID-19 outcomes, including increased hospitalization, ICU admission, mechanical ventilation, and mortality. The American College of Cardiology explicitly identifies obesity as an important cardiovascular risk factor for poor COVID-19 outcomes, with risk being incremental such that patients with morbid obesity (BMI >40 kg/m²) face the highest risk 1.
Evidence of Increased Severity and Mortality
The relationship between obesity and COVID-19 severity is dose-dependent and well-established across multiple populations:
Patients with BMI 40-44 kg/m² have 2.68 times increased mortality risk compared to normal weight individuals (BMI 18.5-24 kg/m²), while those with BMI ≥45 kg/m² face 4.18 times increased mortality risk, even after controlling for age, sex, and cardiovascular comorbidities 1
Obese patients are significantly more likely to require intubation (43.4% vs 31.9% in non-obese patients) 1
Among critically ill ICU patients in New York City, 46% were obese, and obesity was associated with greater need for mechanical ventilation (18.3% vs 15.7%) 1
A large meta-analysis demonstrated obesity increases risk of severe disease by 52% (RR=1.52,95% CI 1.41-1.63) and mortality by 9% (RR=1.09,95% CI 1.02-1.16) 2
Mechanisms of Increased Risk
Obesity creates multiple physiological vulnerabilities that worsen COVID-19 outcomes:
Adipose tissue expansion increases release of inflammatory proteins contributing to cytokine storm in critically ill patients 1
Elevated ACE2 receptor expression associated with high-fat diets provides increased viral entry points 1
Impaired humoral and cellular immunity, along with lower vaccine-induced immunity 1
Hyperinsulinism and insulin resistance impair immune cell activation and anti-inflammatory responses 1
Visceral adipose tissue mass specifically correlates with ICU admission and need for invasive mechanical ventilation 1
Age-Independent Risk
Obesity shifts severe COVID-19 risk to younger populations:
Even among young adults, morbid obesity (BMI >40 kg/m²) was independently associated with death or mechanical ventilation during hospitalization 1
In patients aged <65 years, obesity (≥30 kg/m²) was associated with increased risk of death or intubation independent of other comorbidities 1
There is a significant inverse correlation between age and BMI, with younger hospitalized patients more likely to be obese 1
Compounding Comorbidities
Obesity contributes to and exacerbates other high-risk conditions:
Obesity is linked to hypertension, diabetes, sleep apnea, and secondary pulmonary hypertension—all independent COVID-19 risk factors 1
Combined overweight and obesity prevalence ranges from 48-70% in hospitalized COVID-19 patients and increases further in critically ill patients 1
Overweight or obesity is associated with 2-fold increased risk of hospitalization compared to normal or underweight individuals 1
Clinical Implications and Priority Status
Major medical societies explicitly recommend prioritizing obese patients:
The American College of Cardiology recommends patients with morbid obesity be considered higher risk compared to those who are overweight, and should be prioritized for COVID-19 vaccination 1
Obese individuals, especially those with higher BMIs, should be prioritized for COVID-19 vaccination according to 2022 guidelines 1
The European Society for Clinical Nutrition and Metabolism recommends obese individuals, especially older adults with multiple comorbidities, be screened for nutritional risk 1
Important Caveats
The BMI-mortality relationship shows a J-shaped curve:
Low BMI (<18.5 kg/m²) is also associated with worse outcomes (RR: 1.81), likely due to frailty or cachexia from comorbid conditions 1
This means both extremes of weight require heightened clinical vigilance 1
Obesity represents the only modifiable major risk factor that is not routinely treated in COVID-19 management, despite evidence that treatment can improve visceral adiposity, insulin sensitivity, and mortality risk 3. Pharmacological interventions targeting metabolic abnormalities associated with obesity (antihypertensive, glucose-lowering, and lipid-lowering treatments) significantly reduce risk of severe COVID-19 even after vaccination 4.