Higher body mass index is strongly linked to poor outcomes in adult COVID-19 hospitalizations: A National Inpatient Sample Study.

Aims: The coronavirus disease 2019 (COVID-19) pandemic has resulted in more than 6 million deaths worldwide. Studies on the impact of obesity on patients hospitalized with COVID-19 pneumonia have been conflicting, with some studies describing worse outcomes in patients with obesity, while other studies reporting no difference in outcomes. Previous studies on obesity and critical illness have described improved outcomes in patients with obesity, termed the "obesity paradox." The study assessed the impact of obesity on the outcomes of COVID-19 hospitalizations, using a nationally representative database. Materials and Methods: ICD-10 code U071 was used to identify all hospitalizations with the principal diagnosis of COVID-19 infection in the National Inpatient Database 2020. ICD-10 codes were used to identify outcomes and comorbidities. Hospitalizations were grouped based on body mass index (BMI). Multivariable logistic regression was used to adjust for demographic characteristics and comorbidities. Results: A total of 56,033 hospitalizations were identified. 48% were male, 49% were white and 22% were black. Patients hospitalized with COVID-19 pneumonia in the setting of obesity and clinically severe obesity were often younger. Adjusted for differences in comorbidities, there was a significant increase in mortality, incidence of mechanical ventilation, shock, and sepsis with increased BMI. The mortality was highest among hospitalizations with BMI ≥60, with an adjusted odds ratio of 2.66 (95% Confidence interval 2.18-3.24) compared to hospitalizations with normal BMI. There were increased odds of mechanical ventilation across all BMI groups above normal, with the odds of mechanical ventilation increasing with increasing BMI. Conclusion: The results show that obesity is independently associated with worse patient outcomes in COVID-19 hospitalizations and is associated with higher in-patient mortality and higher rates of mechanical ventilation. The underlying mechanism of this is unclear, and further studies are needed to investigate the cause of this.