Background: There is mounting evidence related to the association between obesity and severity of COVID-19. However, the direct relationship of the increase in the severe COVID-19 risk factors, with an increase in body mass index (BMI), has not yet been evaluated. Aim: This meta-analysis aims to evaluate the dose–response relationship between body mass index (BMI) and poor outcome in patients with COVID-19. Methods: A systematic literature search was conducted using PubMed, Europe PMC, ProQuest, and the Cochrane Central Database. The primary outcome was composite poor outcome composed of mortality and severity. The secondary outcomes were mortality and severity. Results: A total of 34,390 patients from 12 studies were included in this meta-analysis. The meta-analysis demonstrated that obesity was associated with composite poor outcome (OR 1.73 [1.40, 2.14], P < 0.001; I2: 55.6%), mortality (OR 1.55 [1.16, 2.06], P = 0.003; I2: 74.4%), and severity (OR 1.90 [1.45, 2.48], P < 0.001; I2: 5.2%) in patients with COVID-19. A pooled analysis of highest BMI versus reference BMI indicate that a higher BMI in the patients was associated with composite poor outcome (aOR 3.02 [1.82, 5.00], P < 0.001; I2: 59.8%), mortality (aOR 2.85 [1.17, 6.92], P = 0.002; I2: 79.7%), and severity (aOR 3.08 [1.78, 5.33], P < 0.001; I2: 11.7%). The dose–response meta-analysis showed an increased risk of composite poor outcome by aOR of 1.052 [1.028, 1.077], P < 0.001 for every 5 kg/m2 increase in BMI (Pnon-linearity < 0.001). The curve became steeper with increasing BMI. Conclusion: Dose–response meta-analysis demonstrated that increased BMI was associated with increased poor outcome in patients with COVID-19.
- Body mass index