In people with obesity, weight loss achieved through metabolic surgery was associated with improved outcomes after COVID-19, according to a study published in JAMA Surgery (2021 Dec 29. doi:10.1001/jamasurg.2021.6496).

The finding comes from a retrospective cohort of 5,053 adult patients who underwent weight loss surgery between Jan. 1, 2004, and Dec. 31, 2017, at the Cleveland Clinic Health System and 15,159 propensity score–matched patients who did not have metabolic surgery.

Patients tested positive for SARS-CoV-2 at about the same rate in both groups: 9.1% among surgical patients and 8.7% in the nonsurgical arm. However, individuals who had undergone weight loss surgery had a 49% lower risk for hospitalization, 63% lower risk for need for supplemental oxygen and a 60% lower risk for severe disease during a 12-month period after contracting COVID-19.

The researchers, led by Ali Aminian, MD, the director of the Bariatric and Metabolic Institute at Cleveland Clinic, said the findings “represent the best available evidence on the implications of a successful weight loss intervention for COVID-19 outcomes.”

There is an established link between obesity and poor outcomes after COVID-19 infection. But this study demonstrates that obesity is a modifiable risk factor. By losing weight several years earlier with surgery, patients had a reduced risk for adverse outcomes with COVID-19.

At the time of their COVID-19 diagnosis, patients in the surgical group had achieved 20.0 kg lower body weight and better glycemic control compared with presurgical levels. They’d lost 18.6% more body weight over time compared with patients who didn’t undergo surgery.

Patients with substantial and sustained weight loss “were likely physically and physiologically better equipped to cope with an infection that has the potential for multiorgan involvement,” the authors concluded.

Three-fourths of patients were female; they were a mean age of 46 years. The study excluded anyone with a history of organ transplant, cancer or precancerous diagnosis, alcohol use disorder or alcohol-related medical condition, dialysis, ascites, cardiac ejection fraction less than 20%, HIV, peptic ulcer disease, or a recent emergency department admission before surgery.

The study has significant limitations due to its retrospective design, including unknown confounders, misclassification bias, patients lost to follow-up and control selection bias. Moreover, the study did not compare patients who were actively pursuing medical or behavioral interventions for obesity. It shows only that successful weight loss can be protective against severe COVID-19 complications.

In an invited commentary, Paulina Salminen, MD, PhD, of the Department of Surgery at the University of Turku, in Finland, and her colleagues argued that metabolic surgery should be considered medically necessary (JAMA Surg 2021 Dec 29. doi:10.1001/jamasurg.2021.6549).

At many places around the country, weight loss surgery is classified as an elective procedure and was put on hold during surges of COVID-19 to preserve scarce healthcare resources.

“As the COVID-19 pandemic continues, health care professionals who make decisions regarding health care use must acknowledge the cumulating evidence of obesity as a modifiable disease that is a predisposing factor for COVID-19 infection, as supported by this current study,” Dr. Salminen and her colleagues wrote.

In June 2020, the American Society for Metabolic and Bariatric Surgery issued a statement, saying metabolic and bariatric surgery should not be considered elective (Surg Obes Relat Dis 2020;16[8]:981-982).

The organization said these operations are “medically necessary and the best treatment for those with the life-threatening and life-limiting disease of severe obesity.”