Patients were divided into six groups based on BMI. Out of the 3530 patients included in this analysis, 1579 were women, 896 had a BMI below 25 kg/m2, 1162 had a BMI of 25-29 kg/m2, 809 had a BMI of 30-34 kg/m2 (class I obesity), and 663 had a BMI of 35 kg/m2 or higher (class II and III obesity).

The authors investigated associations between these groups and death in hospital, the need for intubation and the development of severe pneumonia.

The authors found that patients with class II and III obesity had a higher likelihood of in-hospital mortality, especially when compared to patients in the normal weight group, and that this association was stronger as obesity class increased. These patients were also more likely to develop severe pneumonia and to undergo intubation.

In men, both class II (BMI 35-40kg/m2) and class III obesity (BMI higher than 40kg/m2) were associated with higher risk of death, while the same was only the case for women in obesity class III.

Systemic inflammation was assessed by measuring levels of the cytokine interleukin 6 (IL-6). Cytokines are signalling molecules that regulate immunity, inflammation and hematopoiesis, the manufacture of new blood cells.

Arcelia Guerson-Gil, the corresponding author said: “It is known that a major cause of disease severity and death is an excessive inflammatory response to SARS-CoV-2 that is associated with high levels of circulating cytokines, such as IL-6.

Obesity is considered a state of enhanced chronic inflammation, so we suspected there may be an association between body mass index and systemic inflammation as indicated by IL-6 level. However, we found that this wasn’t the case.”

Patients who died from COVID-19 had higher average levels of IL-6 compared to survivors and that men had higher average levels of IL-6 compared to women. Average IL-6 levels also increased with age.

There is no clear association between IL-6 and obesity. While inflammation may play a role in severe disease and death from COVID-19, it may not be the mechanism that underlies the association between severe disease, death and obesity.

Obesity may increase the risk of worse outcomes in patients with COVID-19 through other mechanisms, such as affected lung function, increased work of breathing or a higher expression of the ACE2 receptor, which allows SARS-CoV-2 to enter cells, in adipose tissue.

The study design does not allow for conclusions about cause and effect and that the rapidly changing management of patients with COVID-19 might have affected the results.

More studies are required to confirm the findings and pilot clinical trials would be useful to assess whether drugs targeting visceral adipose tissue may improve outcomes.

Source: Medindia