Body Mass Index and Morbidity in Patients Hospitalized With COVID-19

bald man in hospital bed receiving oxygen
Old Man and Oxygen Mask
Is body mass index associated with morbidity in patients hospitalized with COVID-19?

In patients who are hospitalized with COVID-19, no association has been demonstrated between obesity and morbidity outcomes, including hospital length of stay (LOS), home discharge, or ventilator-free days. These were among findings of a study recently published in the journal BMJ Open Respiratory Research.

The single-center cohort study was conducted among adults with COVID-19 who were admitted to New York Presbyterian Hospital-Weill Cornell Medicine in New York City between March 3, 2020, and May 15, 2020. The researchers sought to assess the relationship between body mass index (BMI) and clinical outcomes other than death among patients with COVID-19 who were hospitalized and intubated.

The study included a total of 1337 adult patients who were admitted to the hospital with COVID-19 (diagnosed via a positive reverse transcription polymerase chain reaction test), including a subset of 407 intubated patients. Patients were classified into 1 of 5 BMI groups: (1) underweight (<18.5 kg/m2); (2) normal (18.5 kg/m2 to 24.9 kg/m2); (3) overweight (25.0 kg/m2 to 29.9 kg/m2); (4) obese (30.0 kg/m2 to 39.9 kg/m2); and (5) morbidly obese (≥40 kg/m2).

Outcomes of interest included hospital LOS and discharge disposition among admitted and intubated individuals. Further, ventilator-free days at 28 days (VFD28) and at

60 days (VFD60), along with need for tracheostomy, were evaluated among intubated patients. Those individuals who died while they were intubated were assigned a value of zero VFD. After stratification according to BMI category, baseline and outcome variables, along with laboratory and ventilatory parameters, were generated for the admitted and the intubated cohorts.

Among study participants, hospital LOS and home discharge did not differ significantly across BMI categories, independent of comorbidities and demographic characteristics. No difference in in-hospital events and treatments, including prone positioning, neuromuscular blockade, and use of renal replacement therapy, were reported in the intubated cohort.

On days 1, 3, and 7, the ventilatory ratio was higher with increasing BMI. In the intubated cohort, no significant differences related to BMI were seen in VFD28, VFD60, need for tracheostomy, hospital LOS, and discharge disposition, after adjustment for age, sex, and race/ethnicity, then additionally adjusted for chronic obstructive pulmonary disease, asthma, diabetes, hypertension, coronary artery disease, heart failure, end-stage renal disease, cerebrovascular accident, and cancer.

The investigators concluded that although obesity was a risk factor for intubation in the population of patients with COVID-19 who were evaluated, obesity was not related to other adverse outcomes in hospitalized or intubated individuals with COVID-19. They also noted that additional research is warranted to elucidate the mechanisms underlying the reported effects of BMI on patient outcomes, which may be population-dependent.

Disclosure: Some of the study authors have declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 


Plataki M, Pan D, Goyal P, et al. Association of body mass index with morbidity in patients hospitalised with COVID-19. BMJ Open Respir Res. 2021;8(1):e000970. doi:10.1136/bmjresp-2021-000970