New Study Suggests Obesity is Modifiable Risk Factor for Severe COVID-19 Infection

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Among patients with obesity, prior weight loss achieved with bariatric surgery was associated with a 60% lower risk of developing severe COVID-19, according to new research from the Cleveland Clinic.

Although obesity is an established risk factor for severe COVID-19 infection, the new cohort study investigated whether a successful weight loss intervention (ie, metabolic surgery) conducted prior to contracting the virus could improve the outcomes of infection in patients with obesity.

“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 lead author Ali Aminian, MD, director of Cleveland Clinic’s Bariatric & Metabolic Institute, in a statement. “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 and colleagues enrolled 20 212 adults with obesity, including 5053 who underwent weight loss surgery between 2004 and 2017 at the Cleveland Clinic Health System and 15 159 who did not (control group). Patients in the surgical group were matched 1:3 to those in the control group.

Among all participants, the median age was 46 years, the median body mass index was 45 kg/m2, and nearly 78% were women. The overall median follow-up duration was 6.1 years.

Compared with control participants, those in the surgical group lost approximately 19% more body weight and had a 53% lower 10-year cumulative incidence of all-cause non-COVID-19 mortality prior to March 1, 2020 (ie, the start of the COVID-19 outbreak in Cleveland), according to the study.

Among all participants, 11 809 participants were available after the COVID-19 outbreak for an assessment of 4 COVID-19-related outcomes: rate of contracting SARS-CoV-2 infection, hospitalization, need for supplemental oxygen, and severe disease (defined for the purpose of the study as a combination of ICU admission, need for mechanical ventilation, or death).

Investigators found that the rates of positive SARS-CoV-2 test results were comparable in the surgical (9.1%) and control (8.7%) groups; however, receiving bariatric surgery was associated with a 49% lower risk of hospitalization (adjusted hazard ratio [aHR], 0.51; 95% confidence interval [CI], 0.35-0.76; P<.001), a 63% lower risk of need for supplemental oxygen (aHR, 0.37; 95% CI, 0.23-0.61; P<.001), and a 60% lower risk of severe COVID-19 infection (aHR, 0.40; 95% CI, 0.18-0.86; P=.02).

Researchers could not identify the exact underlying mechanisms, but these findings suggest that, “patients with a history of weight loss surgery were generally healthier at the time of contracting SARS-CoV-2, which may be associated with better clinical outcomes,” wrote investigators.

“Striking findings from the current study support the reversibility of the health consequences of obesity in the patients with COVID-19,” said senior author, Steven Nissen, MD, chief academic officer of Cleveland Clinic’s Heart, Vascular and Thoracic Institute, in the press release. “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.”