Prior Bariatric Surgery is Associated with a Reduced Risk of Poor Outcomes in COVID-19: Propensity Matched Analysis of a Large Multi-institutional Research Network.

Purpose Through sustained weight loss and improvement in metabolic co-morbidities, bariatric surgery is hypothesized to reduce the risk of severe COVID-19. Small studies have suggested favorable outcomes; however, large population-based studies are lacking. Materials and methods We conducted a retrospective cohort study utilizing the multi-institutional research network TriNeTx platform. Participants diagnosed with COVID-19 were identified and divided into cohorts based on prior bariatric surgery (BS). Primary study outcome was a composite event of death or requirement for mechanical ventilation up to 30-day following the diagnosis of COVID-19. Other outcomes included death, hospitalization, critical care need, and acute kidney injury in the 30-day follow-up period. Outcomes were compared in BS and non-BS cohorts after propensity score matching. Results There were significant differences in patient demographics and co-morbidities between the BS and non-BS groups. In the propensity score-matched analysis, there was a lower risk of reaching the primary endpoint of mechanical ventilation or mortality at 30 days after COVID-19 diagnosis in the BS cohort compared to the non-BS cohort (risk ratio (RR) 0.40, 95% CI 0.25-0.65). Mortality rate was lower in the BS cohort (RR 0.42, 95% CI 0.22-0.80), and patients in the BS group were less likely to require critical care (RR 0.54, 95% CI 0.38-0.77), mechanical ventilation (RR 0.43, 95% CI 0.24-0.78) or develop acute kidney injury (RR 0.57, 95% CI 0.43-0.76) after COVID-19 diagnosis. Conclusion Prior bariatric surgery is associated with a reduced risk of poor outcomes of COVID-19. Furthermore, large prospective studies are needed.