The outcomes from the first meta-analysis reporting the possible protective effects of bariatric surgery in patients with COVID-19 infection indicates that prior bariatric surgery is associated with a lower rate of mortality and hospital admission in patients with obesity who become infected with SARS-CoV-2, according to researchers from the Cleveland Clinic, OH. The findings were published in the paper, ‘Association of Bariatric Surgery with Clinical Outcomes of SARS-CoV-2 Infection: a Systematic Review and Meta-analysis in the Initial Phase of COVID-19 Pandemic’, in Obesity Surgery.
For the study, the investigators performed a literature search and identified three (Cleveland Clinic Study, University of Minnesota Study and a study from France) retrospective studies including 9,022 patients, 590 of whom had a history of prior bariatric surgery. The primary outcome of this meta-analysis was the difference in mortality rate in patients with SARS-CoV-2 infection with and without prior history of bariatric surgery, and the secondary outcome was the difference in hospitalisation rate in patients with SARS-CoV-2 infection with and without prior history of bariatric surgery.
The Cleveland study (Aminian A, et al. Association of prior metabolic and bariatric surgery with severity of COVID-19 in patients with obesity) included 4,365 patients with 33 patients having a prior history of bariatric surgery. When the surgical patients were propensity matched (1:10) to nonsurgical patients the multivariate analysis found that prior history of surgery was associated with a lower hospital admission rate vs control patients with obesity (p=0.028). While none of the four exploratory outcomes occurred in the bariatric surgery group, 43 (13.0%) patients in the control group required ICU admission (p=0.021), 22 (6.7%) required mechanical ventilation, five (1.5%) required dialysis and eight (2.4%) patients died.
The University of Minnesota study (Bramante C, et al. Non-alcoholic fatty liver disease (NAFLD) and risk of hospitalization for Covid-19) showed that a history of nonalcoholic fatty liver disease (NAFLD) was associated with increased odds of hospital admission after SARS-CoV-2 infection. Among 373 patients with NAFLD, the subgroup of patients who had undergone bariatric surgery (n=16) had significantly decreased odds of hospitalisation (p<0.05).
The French study (Iannelli A, et al. The impact of previous history of bariatric surgery on outcome of COVID-19. A Nationwide Medico-Administrative French Study) included 8,286 patients of whom 541 had a history of bariatric surgery between 2010 and 2019. The need for an invasive mechanical ventilation and death occurred in 7% and 3.5% in the bariatric surgery group versus 15% and 14.2% in the non-bariatric surgery group, respectively (both p<0.0001). The logistic regression analysis showed that prior bariatric surgery was associated with a lower risk of invasive mechanical ventilation (p=0.025) and mortality (p=0.00).
From the three studies, the overall risk of mortality without previous bariatric surgery was 133 per 1000 cases and its risk with previous bariatric surgery was 33 per 1,000.
The Cleveland and University of Minnesota studies reported a lower risk of hospitalization in patients with prior bariatric surgery after contracting SARS-CoV-2 infection. In the pooled analysis, the hospitalisation rate in patients without previous bariatric surgery was 412 per 1,000 cases and its rate in patients with previous bariatric surgery was 164 per 1,000.
“The current meta-analysis suggests that prior history of bariatric surgery may mitigate the expected severity of COVID-19 in patients with obesity. In patients who had prior bariatric surgery, the odds of hospitalization was 72% lower than that in the control group (41% vs 16% favouring bariatric surgery group). Furthermore, the odds of mortality after contracting SARS-CoV-2 infection was 78% lower compared with that in the control group (13% vs 3% favouring bariatric surgery group)…” the authors report. “Confirmation of these findings will require larger studies with better quality data.”
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