- In the 2009 H1N1 pandemic, obesity was identified as a risk factor for fatal and critical complications of influenza.1,3,4
- Obesity appears to be an independent risk factor for severe COVID-19 infection: 5
- The need for invasive mechanical ventilation increases with body mass categories, reaching nearly 90% in ICU patients with a BMI > 35 kg/m2. 1
- While patients aged < 60 years are generally considered a low risk group of COVID-19 disease severity, obesity appears to be a previously unrecognized risk factor for hospitalization and need for critical care in this age group.2
- Several mechanistic hypotheses have been proposed to explain these association:
- Obesity is associated with an increased risk of respiratory dysfunction: altered respiratory mechanics, increased airway resistance, impaired gas exchange, low respiratory muscle strength and low lung volumes. 7
- Obesity is a risk factor for certain comorbid conditions (hypertension, diabetes, cardiovascular disease, thrombosis) that are associated with higher fatality.7
- Adipose tissue could prolong the duration of viral shedding, which could activate the immune response and thus strengthen the cytokine cascade. 6
These data come from five different retrospective studies that evaluated the obesity as a potential risk factor for severity, hospital admissions or death.
- Simonnet A., Chetboun M., Poissy J., et al. (April 9, 2020). High prevalence of obesity in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) requiring invasive mechanical ventilation. Obesity. https://doi.org/10.1002/oby.22831
A single center retrospective cohort study including 124 patients admitted to Roger Salengro Hospital intensive care unit (CHU Lille, France) between February 27th and April 5, 2020, analyzing the relationship between clinical characteristics and the requirement for invasive mechanical ventilation.
- Lighter J., Phillips M., Hochman S., et al. Obesity in patients younger than 60 years is a risk factor for Covid-19 hospital admission. Clin Infect Dis 2020. https://doi.org/10.1093/cid/ciaa415
A retrospective study of 3615 symptomatic patients in New York between March 4, 2020 and April 4, 2020, investigating the effect of obesity on hospital admissions and the need for intensive care
- Moser J.S., Galindo-Fraga A., Ortiz-Hernandez A.A., et al. Underweight, overweight, and obesity as independent risk factors for hospitalization in adults and children from influenza and other respiratory viruses. Influenza Other Respir Viruses. https://doi.org/10.1111/irv.12618
An observation study of 4778 patients with influenza‐like illness in six hospitals in Mexico, investigating the relationship between obesity and risk of complications
- Ong S. W. X., Young B. E., Leo Y.-S., et al. (May 8, 2020). Association of higher body mass index (BMI) with severe coronavirus disease 2019 (COVID-19) in younger patients. Clinical Infectious Disease. https://doi.org/10.1093/cid/ciaa548
A retrospective study of 182 confirmed cases admitted to the National Centre for Infectious Diseases, Singapore, investigating the relation between higher BMI and severe disease manifestations.
- Petrilli C. M., Jones S. A., Yang J., et al. (April 11, 2020). Factors associated with hospitalization and critical illness among 4,103 patients with COVID-19 disease in New York City. https://doi.org/10.1101/2020.04.08.20057794
A cross-sectional analysis of COVID-19 confirmed cases in New York City between March 1, 2020 and April 2, 2020, studying the factors associated with hospitalization and critical illness.
- Ryan P. M. and Caplice N. M. (April 21, 2020). Is Adipose Tissue a Reservoir for Viral Spread, Immune Activation and Cytokine Amplification in COVID-19. https://doi.org/10.1002/oby.22843
The authors propose a theory to explain the relationship between obesity and severe manifestations, where adipose tissue would be a reservoir of amplification for viral spread.
- Stefan N., Birkenfeld A. L., Schulze M. B., et al. (April 23, 2020). Obesity and impaired metabolic health in patients with COVID-19. Nature Reviews Endocrinology. https://doi.org/10.1038/s41574-020-0364-6
The authors review results of published studies on the relationship between obesity and COVID-19.