Bariatric Surgery May Improve COVID-19 Outcomes in Patients with Obesity

December 16, 2020
Grace Halsey

Among patients with obesity who contracted COVID-19, those with a history of bariatric surgery had significantly decreased odds of hospitalization, a new study finds.

Among patients who have obesity who tested positive for COVID-19, a history of bariatric surgery was associated with nearly 3 times lower odds of hospital admission as well as with lower risk of admission to the intensive care unit (ICU).

Results of the study conducted by researchers at the Cleveland Clinic were published in the journal Surgery for Obesity and Related Diseases.

Early in the COVID-19 pandemic, patients with obesity appeared to become extremely ill with the infection. More recently, researchers worldwide have identified obesity as a risk factor for a severe form of the disease that may lead to hospitalization, admission to intensive care, and use of a ventilator.

Obesity is a complex disease caused by multiple factors that weaken the immune system. Despite a diluted immune response, however, “Infection with the coronavirus also triggers the immune system to release cytokines, which may lead to excessive cytokine production that damages organs,” said principal investigator Ali Aminian, MD, director of the Bariatric and Metabolic at Cleveland Clinic in a clinic press release. “That may partly explain the severity of infection in patients with obesity.”

In this retrospective, matched-cohort analysis of a prospective clinical registry, Aminian and colleagues looked at 4,365 patients who tested positive for SARS-CoV-2 between March 8, 2020 and July 22, 2020 and identified 33 patients who had a prior history of weight-loss surgery (20, sleeve gastrectomy; 13, Roux-en-Y gastric bypass). The 33 surgical patients were propensity matched 1:10 to nonsurgical patients with obesity for a final cohort of 330 control patients with a body mass index (BMI) of ≥40 kg/m2 at the time of SARS-CoV-2 testing.

The primary endpoint was the rate of hospital admission. The exploratory endpoints included admission to the ICU, need for mechanical ventilation and dialysis during index hospitalization, and mortality. After propensity score matching, outcomes were compared in univariate and multivariate regression models.

The average BMI of the surgical group was 49.1 ± 8.8 kg/m2 before metabolic surgery and was down to 37.2 ± 7.1 at the time of SARS-CoV-2 testing, compared with the control group’s BMI of 46.7 ± 6.4 kg/m2.

In the univariate analysis, 6 (18.2%) patients in the metabolic surgery group and 139 (42.1%) patients in the control group were admitted to the hospital (P = .013).

In the multivariate analysis, a prior history of metabolic surgery was associated with a lower hospital admission rate compared with control patients with obesity (odds ratio, 0.31; 95% confidence interval, 0.11−0.88; P = .028).

None of the 4 exploratory outcomes occurred in the metabolic surgery group, but among patients in the control group:

  • 43 (13.0%) required ICU admission (P = .021)
  • 22 (6.7%) required mechanical ventilation
  • 5 (1.5%) required dialysis
  • 8 (2.4%) patients died

In their discussion the authors that noted that individuals in the surgical group had not only lost an average of 12.6 kg/m2 but a number of them also experienced remission of diabetes and reduced or no need for antihypertensive medications.

“Patients after bariatric surgery become significantly healthier and can fight the virus better,” added Aminian in the press release. “If confirmed by future studies, this can be added to the long list of health benefits of bariatric surgery such as improvement of diabetes, hypertension, fatty liver disease, sleep apnea, and prevention of heart attack, stroke, kidney disease and death.”

Limitations to the study include the small sample size, resulting in wide confidence intervals that could have affected statistical comparisons and the absence of laboratory, radiologic, and oxygen use data.