A new study has found that COVID-19 patients who are overweight or obese are more likely to develop a more severe infection than patients of healthy weight, and they require oxygen and invasive mechanical ventilation more often.

For our comprehensive coverage and latest updates on COVID-19 click here.

The findings of the study were published in the journal 'Diabetes Care'. While obese people are at a higher risk of developing a more serious infection, there is no increased risk of death. These conclusions, for which more than 7,000 patients were studied, appear from international research in eleven countries, including the Netherlands (Radboud university medical centre).

The study, led by Australian researchers, examined over 7000 patients from eleven different countries who were admitted to 18 hospitals. Of this group, over a third (34.8 per cent) were overweight and almost a third (30.8 per cent) were obese. COVID-19 patients with obesity required oxygen more frequently and were 73 per cent more likely to require invasive mechanical ventilation. Remarkably, no greater mortality was observed in these groups of patients than in patients of healthy weight.

Immunologist Siroon Bekkering of Radboud university medical centre, principal investigator of the Dutch part, explained that never before so many different data on obesity have been combined in one large study. "Several national and international observations already showed the important role of overweight and obesity in a more severe COVID-19 course. This study adds to those observations by combining data from several countries with the possibility to look at the risk factors separately. Regardless of other risk factors (such as heart disease or diabetes), we now see that too high a BMI can actually lead to a more severe course in corona infection", Bekkering said.

One explanation for this is that overweight and obesity are characterized by chronic inflammation, which can perhaps lead to increased susceptibility to viruses. This is also the case with the flu virus. Also, obese people are more likely to suffer from shortness of breath, which may lead to an increased need for ventilation.

More risk factors emerge from the study. For example, this study, similar to other international studies, confirms that men are more likely to have a more severe course of COVID-19 infection. In addition, this study also shows that people older than 65 years of age needed supplemental oxygen more often and are at greater risk of death.

Cardiovascular disease and pre-existing respiratory disease may be associated with an increased risk of in-hospital death, but not with an increased risk of using oxygen and mechanical ventilation. For patients with diabetes, there was an increased risk of needing invasive respiratory support, but no additional increase in risk in those with both obesity and diabetes. There was no increased risk of death.