Surgery induced weight loss can reduce risk of severe COVID-19 complications

Patients with obesity who previously achieved weight loss with bariatric surgery were associated with a 60% lower risk of developing severe complications from COVID-19 infection, according to the outcomes from a Cleveland Clinic study. The findings were reported in the paper, ‘Association of Weight Loss Achieved Through Metabolic Surgery With Risk and Severity of COVID-19 Infection’, published in JAMA Surgery.

"The research findings show that patients with obesity who achieved substantial and sustained weight loss with bariatric surgery prior to a COVID-19 infection reduced their risk of developing severe illness by 60 percent," said Dr Ali Aminian, lead author of the study and director of Cleveland Clinic's Bariatric & 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."


Previous studies have established obesity as a major risk factor for developing serious illness from an infection of SARS-CoV-2, the virus that causes COVID-19. Obesity weakens the immune system, creates a chronic inflammatory state, and increases risk for cardiovascular disease, blood clots, and lung conditions. All of these conditions can complicate COVID-19.


The aim of this study was to examine whether a successful weight-loss intervention in patients with obesity prior to contracting COVID-19 could reduce the risk of developing a severe form of this disease.


A total of 20,212 adult patients with obesity were included in this observational study. A group of 5,053 patients with BMI>35 who had bariatric surgery between 2004 and 2017 were carefully matched 1:3 to non-surgical patients, resulting in 15,159 control patients. Compared with those in the non-surgical group, patients who had bariatric surgery lost 19% more body weight prior to March 2020 (the beginning of the COVID-19 outbreak in Cleveland).


After the COVID-19 outbreak, researchers looked at four COVID-19-related outcomes: rate of contracting SARS-CoV-2 infection, hospitalization, need for supplemental oxygen and severe disease (defined as a combination of ICU admission, need for mechanical ventilation or death).

Although the rate of contracting SARS-CoV-2 was similar between the groups (9.1% in the surgical group and 8.7% in the non-surgical group), participants in the bariatric surgery group experienced much better outcomes after contracting COVID-19 vs those in the non-surgical group. Researchers found that patients with prior weight loss surgery had a 49% lower risk of hospitalisation (p<0.001), 63% lower risk of need for supplemental oxygen (p<0.001) and 60% lower risk of developing severe COVID-19 (p=0.02).


Although the exact underlying mechanisms are not known, these data suggest that patients who underwent weight-loss surgery were healthier at the time of contracting a SARS-CoV-2 infection, which resulted in better clinical outcomes.


"Striking findings from the current study support the reversibility of the health consequences of obesity in the patients with COVID-19," said the study's senior 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. That is a very important finding considering that 40% of Americans have obesity."


Further information

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