Association of Body Mass Index with Multiple Organ Failure in Hospitalized Patients with COVID-19: A Multicenter Retrospective Cohort Study

Abstract

Purpose: This study examines whether excessive adipose tissue, as measured by the body mass index (BMI), is associated with higher systemic markers of inflammation and higher risk of severe acute organ failure among patients with coronavirus disease 2019 (COVID-19). Methods: This was a multicenter retrospective cohort study of 1370 hospitalized adults (18 years or older) with COVID-19 during the first wave of the pandemic. Patient-level variables were extracted from the electronic medical record. The primary predictor variable was the BMI at time of hospital admission, in accordance with the World Health Organization classification. Multivariable logistic regression analyses examined the association of BMI with the composite of acute respiratory distress syndrome (ARDS), as defined by the use of high-flow nasal canula, non-invasive ventilation, or mechanical ventilation, severe acute kidney injury (AKI), as defined by acute dialysis requirement, or in-hospital death. Results: After adjustment for important cofounders, the BMI stratum of > 40 kg/m² (compared to the BMI < 25 kg/m² reference group) was associated with higher odds for the composite of ARDS, severe AKI, or in-hospital death (adjusted odds ratio [OR_adj] 1.69; 95% confidence interval [CI]1.03, 2.78). As a continuous variable, BMI (per 5-kg/m² increase) remained independently associated with the composite outcome (OR_adj 1.13; 95% CI 1.03, 1.23); patients in higher BMI categories exhibited significantly higher peak levels of C-reactive protein (CRP), a systemic marker of inflammation (P = .01). In a sub-cohort of 889 patients, the association of BMI with the composite outcome was no longer significant after adjustment for the peak level of CRP. Conclusions: Among hospitalized patients with COVID-19, a higher BMI is associated with higher risk of severe organ failure or in-hospital death, which dissipates after adjustment for CRP level. This supports the hypothesis that inflammation is a downstream mediator of adipose tissue on acute organ dysfunction.