Obesity Outcomes In Acute Respiratory Distress Syndrome Due To Covid-19: A Retrospective Single Center Experience

Introduction: The “obesity paradox” has been reported in critically ill patients with acute respiratory distress syndrome (ARDS). Obese patients with ARDS were shown to have more ventilator free days and lower mortality compared to non-obese patients. One proposed explanation was increased levels of pro-inflammatory cytokines creating a protective environment from acute inflammation. In COVID-19, BMI ≥ 30 increases risk of illness severity, need for critical care, respiratory failure requiring use of invasive mechanical ventilation (IMV), and mortality. It is unknown if the “obesity paradox” applies to patients with SARS-CoV2 who require IMV. We examined a cohort of patients with respiratory failure due to COVID-19 who required IMV and compared outcomes between obese and non-obese patients. Methods: Data was collected from patients treated in the COVID Intensive Care Unit (ICU) from March to June 2020. A total of 85 patients were identified. All patients were COVID nasopharyngeal swab positive. Results: There were 38 (44.7%) patients with BMI < 30, and 47 (55.3%) with BMI ≥ 30. The median BMI was 25.5 in the BMI < 30 group, and 37.5 in the BMI ≥ 30 group. In the BMI < 30 group, median age was 67 years, majority male (65.8%) and African American (50%). The BMI ≥ 30 group had a median age of 63.5, majority male (53.2%) and African American (63.8%). Median Sequential Organ Failure Assessment score on admission was higher in the BMI ≥ 30 group at 3 (1.5-4.5) vs. 2 (1.0-4.0). There was elevated creatinine on admission with higher percentage of diabetes, heart failure, and renal disease in the BMI ≥ 30 group. Inflammatory markers, such as CRP and IL-6 were lower in the higher BMI group at presentation. There was higher in-hospital mortality in the BMI ≥ 30 group at 57.5%, with longer ICU length of stay (12.35 vs. 7.6 days), longer days on ventilator (10.2 vs. 4 days), and lower PaO2/FiO2 ratio after intubation (146 vs 348). The higher BMI group had higher rates of prone ventilation, paralytic use, and extracorporeal membrane oxygenation support. Discussion: From our data, obesity did not appear to have better outcomes in ARDS due to COVID-19 infection. Higher BMI was associated with higher disease severity, severe respiratory failure, longer ventilator days, longer ICU length of stay, and higher mortality. Interestingly, inflammatory markers were initially lower in obese patients, suggesting a possible adaptive physiologic response to inflammation, but without effect on overall outcomes.