LAUSR

Importance Obesity is an established risk factor for severe COVID-19 infection. However, it is not known whether losing weight is associated with reduced adverse outcomes of COVID-19 infection. Objective To investigate the association between a successful weight loss intervention and improved risk and severity of COVID-19 infection in patients with obesity. Design, Setting, and Participants This cohort study involved adult patients with a body mass index of 35 or higher (calculated as weight in kilograms divided by height in meters squared) who underwent weight loss surgery between January 1, 2004, and December 31, 2017, at the Cleveland Clinic Health System (CCHS). Patients in the surgical group were matched 1:3 to patients who did not have surgical intervention for their obesity (control group). The source of data was the CCHS electronic health record. Follow-up was conducted through March 1, 2021. Exposures Weight loss surgery including Roux-en-Y gastric bypass and sleeve gastrectomy. Main Outcomes and Measures Distinct outcomes were examined before and after COVID-19 outbreak on March 1, 2020. Weight loss and all-cause mortality were assessed between the enrollment date and March 1, 2020. Four COVID-19-related outcomes were analyzed in patients with COVID-19 diagnosis between March 1, 2020, and March 1, 2021: positive SARS-CoV-2 test result, hospitalization, need for supplemental oxygen, and severe COVID-19 infection (a composite of intensive care unit admission, need for mechanical ventilation, or death). Results A total of 20 212 patients (median [IQR] age, 46 [35-57] years; 77.6% female individuals [15 690]) with a median (IQR) body mass index of 45 (41-51) were enrolled. The overall median (IQR) follow-up duration was 6.1 (3.8-9.0) years. Before the COVID-19 outbreak, patients in the surgical group compared with control patients lost more weight (mean difference at 10 years from baseline: 18.6 [95% CI, 18.4-18.7] percentage points; P < .001) and had a 53% lower 10-year cumulative incidence of all-cause non-COVID-19 mortality (4.7% [95% CI, 3.7%-5.7%] vs 9.4% [95% CI, 8.7%-10.1%]; P < .001). Of the 20 212 enrolled patients, 11 809 were available on March 1, 2020, for an assessment of COVID-19-related outcomes. The rates of positive SARS-CoV-2 test results were comparable in the surgical and control groups (9.1% [95% CI, 7.9%-10.3%] vs 8.7% [95% CI, 8.0%-9.3%]; P = .71). However, undergoing weight loss surgery was associated with a lower risk of hospitalization (adjusted hazard ratio [HR], 0.51; 95% CI, 0.35-0.76; P < .001), need for supplemental oxygen (adjusted HR, 0.37; 95% CI, 0.23-0.61; P < .001), and severe COVID-19 infection (adjusted HR, 0.40; 95% CI, 0.18-0.86; P = .02). Conclusions and Relevance This cohort study found that, among patients with obesity, substantial weight loss achieved with surgery was associated with improved outcomes of COVID-19 infection. The findings suggest that obesity can be a modifiable risk factor for the severity of COVID-19 infection.