The Impact of Morbid Obesity on Patients with COVID-19 who Develop Respiratory Failure requiring Extracorporeal Membrane Oxygenation

ABSTRACT

Background: In patients with COVID-19 and respiratory failure, class 3 obesity (body mass index > 40 kg/m2) has been associated with worse survival. Obese patients on mechanical ventilation with progressively more severe acute respiratory syndrome (ARDS) may be offered venovenous (VV) extracorporeal membrane oxygenation (ECMO) therapy. The impact of morbid obesity on the outcome of COVID-19 patients supported with VV ECMO has been underexplored. Methods: This is a multicenter, retrospective observational cohort analysis of critically ill adults with COVID-19 ARDS requiring advanced mechanical ventilation with or without VV ECMO. Data was collected from 236 international institutions forming the COVID-19 Critical Care Consortium international registry. Patients were admitted between January 2020 to December 2021. Included patients were stratified by ECMO status and a BMI threshold at 40 kg/m2. Median values with interquartile range (IQR) were used to summarize continuous variables and multi-state analysis was used to explore the effect of Class 3 obesity on the study endpoints of patient survival to discharge or death. Results: Complete data was available on 8851 of 9059 patients on mechanical ventilation, of which 767 patients required VV ECMO. For the entire study group, older age and male gender were associated with an increased risk of death. The demographics and comorbidities of the higher BMI (H >40 kg/m2) and lower BMI (L ≤40 kg/m2) cohorts were similar with the exception of age and weight. Patients with a higher BMI were younger. The median age of the H, non-ECMO cohort was 56 years (46-64), and the H, ECMO cohort was 41 years (35-51) versus the L, non-ECMO cohort of 64 years(55-71), and the L, ECMO cohort of 53years (45-60). Patients requiring VV ECMO had higher SOFA scores, experienced longer ICU and hospital lengths of stay, and a longer duration of total mechanical ventilation. Table The median time to intubation was longer in the mechanical ventilation only group (2 versus 0 days). Predictors for requiring ECMO included younger age, higher BMI and male gender. Risk factors for death included advancing age (every 10 years), male gender and increasing BMI (every 5kg/m2). The association between BMI and a higher rate of death was reduced in the mechanical ventilation only group (HR 0.92, 95% confidence interval 0.85 to 0.99). Conclusion: In patients with severe ARDS due to COVID-19 requiring mechanical ventilation, the likelihood of progressing to VV ECMO therapy or experiencing death is impacted by age, gender and higher BMI. The cohort of COVID-19 patients that ultimately required ECMO appear to be sicker at time hospital admission owing to the shorter time until mechanical ventilation. It appears the association between increasing BMI and death differs among the ECMO and mechanical ventilation alone cohorts. We would advocate for a prospective study to determine the benefit of VVECMO for the obese patient requiring VV-ECMO for COVID-19 ARDS. (Figure Presented).