By now, most folks know obesity is a leading risk factor for severe COVID-19, but a new study suggests that losing a significant amount of weight can reduce that risk.
“The research findings show that patients with obesity who achieved substantial and sustained weight loss with bariatric [weight-loss] surgery prior to a COVID-19 infection reduced their risk of developing severe illness by 60%,” said lead study author Dr. Ali Aminian, director of the Cleveland Clinic’s Bariatric and Metabolic Institute.
“Our study provides strong evidence that obesity is a modifiable risk factor for COVID-19 that can be improved through a successful weight-loss intervention,” Aminian said in a Cleveland Clinic news release.
The researchers included more than 20,000 adults with obesity in the study. They matched a group of over 5,000 patients with a body mass index of 35 or greater who had weight-loss surgery between 2004 and 2017 with more than 15,000 control patients who didn’t have the surgery, a 1-to-3 ratio.
Patients who had bariatric surgery lost 19% more body weight prior to March 1, 2020, than those in the control group.
Aminian and his colleagues then looked at four COVID-19 outcomes, including the rate of contracting the virus, hospitalization, the need for supplemental oxygen, and severe disease, which they defined as ICU admission, the need for mechanical ventilation or death.
They found that the rate of infection was similar between the surgical and nonsurgical groups, but patients who had weight-loss surgery had a 49% lower risk of hospitalization, a 63% lower risk of the need for supplemental oxygen and a 60% lower risk of developing severe COVID-19.
“Striking findings from the current study support the reversibility of the health consequences of obesity in the patients with COVID-19,” said senior study author Dr. Steven Nissen, chief academic officer of the Heart, Vascular and Thoracic Institute at Cleveland Clinic.
“This study suggests that an emphasis on weight loss as a public health strategy can improve outcomes during the COVID-19 pandemic and future outbreaks or related infectious diseases,” Nissen said in the release. “That is a very important finding, considering that 40% of Americans have obesity.”
The reason that weight loss has such an impact is not clear, but the data suggest that patients who underwent weight-loss surgery were healthier at the time of the infection, which resulted in better outcomes. Obesity also weakens the immune system, creates a chronic inflammatory state, and increases the risk for cardiovascular disease, blood clots and lung conditions, the researchers said.
The research was published online Dec. 29 in the journal JAMA Surgery.