New York, Dec 30 (IANS): People with obesity who had substantial weight loss following bariatric surgery may have a lower risk of severe complications from Covid-19, finds a new study.

The study, published in the journal JAMA Surgery, indicates that among patients with obesity, prior weight loss achieved with bariatric surgery was associated with a 60 per cent lower risk of developing severe complications from Covid-19 infection.

"The research findings show that patients with obesity who achieved substantial and sustained weight loss with bariatric surgery prior to a Covid-19 infection reduced their risk of developing severe illness by 60 per cent," said lead author Ali Aminian from the Cleveland Clinic in the US.

Obesity weakens the immune system, creates a chronic inflammatory state, and increases risk for cardiovascular disease, blood clots, and lung conditions. All of these conditions can complicate Covid-19.

For the study, a total of 20,212 adult patients with obesity were included in this observational study. A group of 5,053 patients with a body mass index (BMI) of 35 or greater who had weight-loss surgery between 2004 and 2017 were carefully matched 1:3 to non-surgical patients, resulting in 15,159 control patients.

Compared with those in the non-surgical group, patients who had bariatric surgery lost 19 per cent more body weight prior to March 1, 2020.

After the Covid-19 outbreak, the team looked at four Covid-19-related outcomes: rate of contracting SARS-CoV-2 infection, hospitalisation, need for supplemental oxygen and severe disease (defined as a combination of ICU admission, need for mechanical ventilation or death).

Although the rate of contracting SARS-CoV-2 was similar between the groups (9.1 per cent in the surgical group and 8.7 per cent in the non-surgical group), participants in the weight-loss surgery group experienced much better outcomes after contracting Covid-19 compared with those in the non-surgical group.

Researchers found that patients with prior weight loss surgery had a 49 per cent lower risk of hospitalisation, 63 per cent lower risk of need for supplemental oxygen, and 60 per cent lower risk of developing severe Covid-19.