Weight Loss Can Reduce Risk of Severe COVID in Obese People, Study Suggests

Weight loss appears to be associated with better COVID outcomes, a new study has suggested.

The researchers behind the study say that public health measures with an emphasis on weight loss "can improve outcomes during the COVID-19 pandemic."

The study's suggestion that people carrying excess weight are at greater risk of severe illness from COVID isn't new; previous studies have established obesity as a COVID risk factor and the U.S. Centers for Disease Control and prevention (CDC) lists obesity as a condition that increases the likelihood of severe illness with COVID, along with other medical conditions like diabetes and cancer.

Last year, U.K. Prime Minister Boris Johnson said his own weight contributed to his COVID hospitalization.

The new study examined whether a successful weight-loss intervention in patients prior to COVID infection had any chance of reducing the risk of developing a severe form of the disease.

To find out, the Cleveland Clinic researchers observed a total of 20,212 adult patients with obesity, 5,053 of whom had had weight-loss surgery between 2004 and 2017. Compared with the non-surgical group, those who had had weight-loss surgery had lost 19 percent more of their body weight prior to March 1, 2020.

After the COVID outbreak, researchers looked at four factors: positive test results, hospitalization, need for supplemental oxygen and severe disease. Severe disease was defined as a combination of ICU admission, the need for mechanical ventilation and death.

Between March 1, 2020, and March 1, 2021, 206 patients in the surgical group and 578 patients in the control group caught COVID. At the time of their positive COVID test, the average body weight of patients was 108.4 kg in the surgical group and 128.4 kg in the control group, for an average difference of 20 kg.

In the surgical group, after catching COVID, 32 patients were hospitalized, 19 patients required supplemental oxygen, eight patients developed the composite outcome of severe COVID infection and two patients died. In the control group, 163 patients were hospitalized, 129 patients required supplemental oxygen, 54 patients developed severe COVID infection and 21 patients died.

Therefore, according to the study, the crude rates in the surgical vs control group were 15.5% vs 28.2% for hospitalization, 9.2% vs 22.3% for the need for supplemental oxygen, 3.9% vs 9.3% for severe COVID infection and 1% vs 3.6% for death.

Small number of infections

Since the number of infections was relatively small, the study notes that its findings should be considered "hypothesis-generating and not conclusive." The study was also not designed to identify the cause of the favorable outcomes in the surgical group.

Throughout the study, weight-loss surgery was defined as either Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG)—both common weight-loss surgeries in the United States.

Dr. Steven Nissen, Chief Academic Officer of the Heart, Vascular and Thoracic Institute at Cleveland Clinic and a co-author of the study, told Newsweek: "Since the pandemic started almost 2 years ago, multiple studies have shown that two main risk factors for poor COVID outcomes are advanced age and obesity. Age is not a modifiable risk factor. But based on the findings of this study, we can conclude that obesity is a modifiable risk factor.

"We have a vulnerable society with 40% of US population suffer from obesity. Epidemic of obesity is everywhere. We hope this study improves public awareness, and inform health care providers and policy makers on benefits of losing weight in the context of COVID.

"Despite the limitations of observational studies, we believe this study provides reasonably strong evidence that obesity is a modifiable risk factor for severe COVID infection and that a successful weight loss intervention can play a significant role in improved COVID-related outcomes."

Nissen added they would expect that similar outcomes would occur if the weight loss was driven by lifestyle changes rather than surgery.

The study, titled Association of Weight Loss Achieved Through Metabolic Surgery With Risk and Severity of COVID-19 Infection, was published in the journal JAMA Surgery on December 29, 2021.

Earlier this year, a study suggested that U.S. diets had shifted more toward ultra-processed foods.

Correction, 5/1/22, 11:36 a.m. ET: The spelling of Dr. Steven Nissen's name has been corrected.

Update, 5/1/22, 11:36 a.m. ET: This article has been updated to include comments from Dr. Steven Nissen.

Person on scales
A file photo of a person standing on a set of scales with a measuring tape in the foreground. The CDC states that obesity is a COVID risk factor. vadimguzhva/Getty