Overweight and obesity as risk factors for COVID-19-associated hospitalisations and death: systematic review and meta-analysis

Abstract

Objective: To quantify the current weight of evidence of the association between overweight and obesity as risk factors for COVID-19-related hospitalisations (including hospital admission, intensive care unit admission, invasive mechanical ventilation) and death, and to assess the magnitude of the association and the potential dose-response relationships.

Design: PubMed, Embase, Cochrane, Web of Sciences, WHO COVID-19 database and Google Scholar were used to identify articles published up to 20 July 2021. Peer-reviewed studies reporting adjusted estimates of the association between overweight or obesity and COVID-19 outcomes were included. Three authors reviewed the articles and agreed. The quality of eligible studies was assessed using the Newcastle-Ottawa Quality Assessment Scale. Random-effects meta-analysis was used to estimate the combined effects.

Results: A total of 208 studies with 3 550 997 participants from over 32 countries were included in this meta-analysis. Being overweight was associated with an increased risk of COVID-19-related hospitalisations (OR 1.19, 95% CI 1.12 to 1.28, n=21 studies), but not death (OR 1.02, 95% CI 0.92 to 1.13, n=21). However, patients with obesity were at increased risk of both COVID-19-related hospitalisations (OR 1.72, 95% CI 1.62 to 1.84, n=58) and death (OR 1.25, 95% CI 1.19 to 1.32, n=77). Similarly, patients with extreme obesity were at increased risk of COVID-19-related hospitalisations (OR 2.53, 95% CI 1.67 to 3.84, n=12) and death (OR 2.06, 95% CI 1.76 to 3.00, n=19). There was a linear dose-response relationship between these obesity categories and COVID-19 outcomes, but the strength of the association has decreased over time.

Conclusion: Being overweight increases the risk of COVID-19-related hospitalisations but not death, while obesity and extreme obesity increase the risk of both COVID-19-related hospitalisations and death. These findings suggest that prompt access to COVID-19 care, prioritisation for COVID-19 vaccination and other preventive measures are warranted for this vulnerable group.

Keywords: COVID-19.

Figure 1

Flow chart of the literature selection process.

Figure 2

Dose-response association between obesity categories and COVID-19 outcomes. A) Hospital admission, B) ICU, C) IMV, D) Death, E) combinations of outcomes, F) Hospital admission + ICU + IMV. ICU, intensive care unit; IMV, invasive mechanical ventilation or intubation. Combinations of outcomes regroups studies whose endpoint was the combination of two or more of the following: hospital admission, ICU, IMV, death or other conditions pertaining to a severe disaese. Hospital admission + ICU + IMV is the pooled estimate of studies included in hospital admision, ICU and IMV.