Publication date: Dec 11, 2025
Obesity is generally recognized as an independent risk factor for poor outcomes in Coronavirus Disease 2019 (COVID-19); however, some studies report a paradoxical protective effect. Findings may be mediated by low muscle mass, a relevant predictor of poor clinical outcomes in critically ill patients. We aimed to investigate the association of body mass index (BMI), baseline low muscle mass index (SMI) and low muscle density (SMD) with clinical outcomes in critically ill patients with COVID-19. This retrospective cohort study was conducted at a tertiary care center in Sao Paulo, Brazil. We included all consecutive patients admitted to the intensive care unit (ICU) from March 1st, 2020, to May 31st, 2021, with a confirmed diagnosis of COVID-19 and who had a measured SMI and SMD by thoracic computed tomography (CT) at admission. SMI and SMD were assessed from a transverse image at the level of the 12 thoracic vertebra (T12), and BMI at admission was calculated. The association between coprimary exposures BMI, low SMI, low SMD and hospital mortality was assessed through multivariable analysis accounting for confounding factors such as age, sex, Simplified Acute Physiology Score 3 (SAPS 3) and comorbidities. A total of 962 patients were included; 63. 7 (+/-15. 3) years; 75. 8% males. SMI was assessed in all patients; however, 33 with contrast CTs were excluded from the SMD analysis. The prevalence of low SMI was 21. 6 % (208/962). The prevalence of low SMD was 22. 7% (211/929). A total of 391 (40. 6%) patients were classified as overweight, and 393 (40. 8%) as having obesity. Hospital mortality was 14. 3%, increasing to 26. 2% for patients aged ≥ 65 years. We found no significant association between BMI, SMI or SMD and hospital mortality. Patients with low SMI were more likely to undergo extracorporeal membrane oxygenation (P = 0. 045), required longer duration of mechanical ventilation (MV) (p
| Concepts | Keywords |
|---|---|
| Brazil | Body Composition |
| Coronavirus | Computed Tomography |
| Hospital | Covid 19 |
| Obesity | Critically ill |
| low muscle density | |
| low muscle mass |
Semantics
| Type | Source | Name |
|---|---|---|
| disease | MESH | obesity |
| disease | MESH | critically ill |
| disease | MESH | COVID-19 |
| disease | MESH | SMD |
| disease | MESH | Sao |
| disease | MESH | included |
| disease | MESH | image |
| disease | MESH | overweight |