Association of Body Mass Index and Other Metabolic Risk Factors with Pneumonia Outcomes in Critically Ill Patients with Coronavirus Disease-19: An International Multicenter Retrospective Cohort Study

Previous studies unveiled a relation between COVID-19 severity and obesity. The aims of this multicenter retrospective cohort study were to disentangle the association of body mass index (BMI) and associated metabolic risk factors, with pneumonia outcomes in critically ill patients with COVID-19, and explore the impact of age and sex on this relationship. Participants were COVID-19 patients admitted in intensive care in 21 centers in Europe, Israel, and USA, between 02/19/2020 and 05/19/2020. The exposure of interest was BMI. The primary and secondary outcomes were the need for invasive mechanical ventilation (IMV), and 28-day mortality. The covariates were age, sex, and diabetes, hypertension, hyperlipidemia, and current smoking. We enrolled 1,461 patients (median age 64 years (Interquartile range (IQR), 40.9-72.0); 73.2% males; median BMI 28.1 kg/m2 (IQR, 25.4-32.3); 1,080 patients (73.9%) required IMV and the 28-day mortality rate was 36.1% (95% confidence intervals (CI), 33.0-39.5).  Adjusted mixed logistic regression model showed a significant relation between BMI and IMV: odds ratio 1.27 (95% CI, 1.12-1.45) per 5 kg/m2 in the whole cohort, and 1.65 (95% CI, 0.97-2.79) per 5 kg/m2 in females under 50 years. Adjusted Cox proportional hazards regression model showed a significant association between BMI and mortality, which was only increased in obesity class III (≥40 kg/m2) (Hazard Ratio 1.68 (95% CI 1.06-2.64). In conclusion, we observed in critically ill COVID-19 patients, a linear association between BMI and the need for IMV, independent of other metabolic risk factors, and more pronounced in younger females, and a non-linear association between BMI and mortality risk. Trial Registration: ClinicalTrials.gov Identifier: NCT04391738 Funding Statement: No specific funding. Declaration of Interests:The authors declared no conflict of interest. Ethics Approval Statement: The study complied with standard operating procedures in place, in accordance with the European Data Protection Directive (95/46/EC) and, upon its entry into force, Regulation (EU) 2016/679 (also referred to as the General Data Protection Regulation (GDPR)), and French CNIL frameworks n° MR004 regarding the processing of personal data in clinical studies. The institutional review board from other centers in USA and Israel approved the retrospective case series as minimal-risk research using data collected for routine clinical practice and waived the requirement for informed consent.