Frozen Mask

Bariatric Surgery: Half the Risk of Death from COVID

Early in the pandemic, a couple of things were clear about COVID risk. First, and most important, age is a person’s biggest risk factor. But that’s obviously not a modifiable risk. Soon after that was apparent, another risk factor became apparent – obesity. The risk linked to obesity was not as great as age, but it can easily double a person’s risk of death. So the obvious question is what to do about it. Some early studies suggested that bariatric surgery might cut the risk of death from COVID in half.

Now a more definitive – albeit observational – study from the Cleveland Clinic offers a strong confirmation that patients who have had bariatric surgery have half the risk of death from COVID compared to comparable patients who have not. JAMA Surgery published this study yesterday.

A Rigorous Cohort Study

Let’s be clear. The evidence for this does not rise to the strength of evidence that a randomized controlled trial provides. It is a very solid cohort study of 20,212 persons with an average BMI of 45. Patient records provided an average six years of follow-up data. Using propensity score matching, the protocol called for a ratio of three nonsurgical patients matched to each surgical patient. In the end, there were 5,053 patients who had bariatric surgery and 15,159 patients who did not.

Note that the surgeries happened well before the pandemic started. Patients in the surgical group reduced their initial high body weight by an average of 20 percent. In the nonsurgical group, weight loss was minimal – two percent.

There was no difference in the risk of COVID infections between the two groups. A total of 784 patients developed the infection. But there was a big difference in the rate of severe infections and death. For the patients in the surgery group the risk of severe infection was cut by more than half – 60 percent. The risk of death was cut in half.

As Good as It Gets

This is the clearest evidence we will get for the benefits of bariatric surgery to cut the risk of death from COVID. The authors, led by Ali Aminian, explain:

“Despite the limitations of retrospective studies (e.g., residual measured or unmeasured confounders, including unknown confounders given that COVID-19 is a new disease; control selection bias; loss to follow-up bias; misclassification bias; or differential information bias), we believe this study provides reasonably strong evidence that obesity is a modifiable risk factor for severe COVID-19 infection and that a successful weight loss intervention can play a role in improved COVID-19–related outcomes. Because conducting clinical trials in this setting is not feasible, the findings of this study represent the best available evidence on the implications of a successful weight loss intervention for COVID-19 outcomes.”

Alongside this study, Paulina Salminen, Gerhard Prager, and Phil Schauer published an editorial that was succinct. COVID-19 now belongs on the long list of health problems that bariatric surgery can reduce.

No doubt, some people will choose to deny that they can reduce their risk from COVID through bariatric surgery, just as others deny the benefits of vaccination. But in both cases, it can be a costly mistake.

Click here for the study, here for the editorial, here and here for further reporting. For more on the implications of COVID in obesity care, click here.

Frozen Mask, photograph by Ted Kyle

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December 30, 2021