Martina Recalde , MPH 1 , 2 , Andrea Pistillo , MSc 1 , Sergio Fernandez-Bertolin , BSc 1 , Elena Roel , MD 1 , 2 , Maria Aragon , MSc 1 , Heinz Freisling , PhD 3 , Daniel Prieto-Alhambra , PhD 4 , 5 , Edward Burn , PhD 1 , 4 , Talita Duarte-Salles , PhD 1
23 July 2021
A comprehensive understanding of the association between body mass index (BMI) and COVID-19 is still lacking.
To investigate associations between BMI and risk of COVID-19 diagnosis, hospitalisation with COVID-19, and death after a COVID-19 diagnosis or hospitalisation (subsequent death), accounting for potential effect modification by age and sex.
Primary care records covering >80% of the Catalan population, linked to region-wide testing, hospital, and mortality records from March to May 2020.
We included 2 524 926 participants. After 67 days of follow-up, 57 443 individuals were diagnosed with COVID-19, 10 862 were hospitalised with COVID-19, and 2467 had a subsequent death. BMI was positively associated with being diagnosed and hospitalised with COVID-19. Compared to a BMI of 22kg/m 2, the HR (95%CI) of a BMI of 31kg/m 2 was 1.22 (1.19-1.24) for diagnosis, and 1.88 (1.75-2.03) and 2.01 (1.86-2.18) for hospitalisation without and with a prior outpatient diagnosis, respectively. The association between BMI and subsequent death was J-shaped, with a modestly higher risk of death among individuals with BMIs ≤19kg/m 2 and a more pronounced increasing risk for BMIs ≥40kg/m 2. The increase in risk for COVID-19 outcomes was particularly pronounced among younger patients.