Poor clinical outcomes among hospitalized obese patients with COVID-19 are related to inflammation and not respiratory mechanics.

Abstract

Introduction: The coronavirus disease 2019 (COVID-19) has infected millions of people worldwide resulting in high morbidity and mortality. Obesity is known to cause metabolic derangements and precipitate worse outcomes from viral pneumonia, potentially secondary to increased inflammation and/or altered respiratory mechanics.

Aim of the study: Our study's aim was to examine the relationships among BMI, systemic inflammation, and respiratory mechanics in determining clinical outcomes.

Materials and methods: This retrospective, observational cohort study included 199 adult patients with confirmed COVID-19 who were hospitalized at a quaternary-referral academic health system. Data were manually extracted from electronic medical records, including baseline demographics and clinical profiles, inflammatory markers, measures of respiratory mechanics, and clinical outcomes. We used the rank-sum test to compare the distributions of BMI and inflammatory markers between those with and without specific clinical outcomes, and the Pearson correlation to measure the correlations between BMI and inflammatory markers or respiratory mechanics.

Results: Higher BMI was associated with worse clinical outcomes, including the need for Intensive Care Unit (ICU) admission, invasive mechanical ventilation (IMV), neuromuscular blockade, and prone positioning, particularly in male patients. Inflammation, as measured by C-reactive protein, lactate dehydrogenase (LDH), ferritin, and D-Dimer, was also increased in both male and female patients who required ICU admission, IMV, neuromuscular blockade, and prone positioning. However, only male patients had a positive correlation of LDH and D-Dimer levels with BMI. There was no correlation between BMI and respiratory mechanics, as measured by static compliance and the response to prone positioning.

Conclusions: Our findings suggest that the metabolic dysfunction and systemic inflammation seen in obesity, and not dysfunctional respiratory physiology, drive the negative clinical outcomes seen in this cohort of hospitalized COVID-19 patients.