Effects of BMI on clinical outcomes in acute respiratory failure requiring invasive mechanical ventilation

Background: in certain acute conditions, obesity has been shown to reduce in-hospital mortality (the obesity paradox). The aim of this study is to analyze the association between different classes of body max index (BMI) and in-hospital mortality, weaning failure and subsequent need for tracheostomy, length of stay and total hospital charge in patients admitted for acute respiratory failure (ARF) requiring invasive mechanical ventilation. Methods: we conducted a retrospective analysis of patients included in the 2016 National Inpatient Sample (NIS). We divided the patients into 13 groups according to their BMI. A multivariate analysis was conducted to adjust for age, gender, race, hospital characteristics, presence of malnutrition and critical care illness, and Charlson comorbidity index. Results: obesity was associated with reduced in-hospital mortality but increased need for tracheostomy when BMIu003e40. Obesity was also associated with increased LOS (when BMIu003e40) and hospital cost. Conclusions: In mechanically ventilated patients, obesity is associated with reduced mortality, increased need for tracheostomy, LOS and hospital charge.