Major weight loss decreases risk of asthma attacks

Substantial weight loss through procedures such as bariatric surgery can significantly reduce the risk of asthma attacks - also called exacerbations - in obese patients with asthma, new research has found.

"We found that in obese patients with asthma the risk of emergency department visits and hospitalisations for asthma exacerbations decreased by half in the two years after bariatric surgery," said the lead author of the study Kohei Hasegawa from Massachusetts General Hospital (MGH).

The researcher said that for the first time it was found that significant weight reduction can reduce serious asthma-associated events.

"Although previous studies of non-surgical weight loss interventions failed to show consistent results regarding asthma risks, our result strongly suggests that the kind of significant weight loss that often results from bariatric surgery can reduce adverse asthma events," Hasegawa said.

In the current study, the researchers identified 2,261 obese patients with asthma who underwent bariatric surgery from 2007 to 2009 and for whom information covering the two years before and after their surgery was available.

The analysis showed that, during the two years prior to surgery, around 22 percent of the studied patients had at least one emergency department (ED) visit or hospitalization in each one-year period.

In the two years after surgery, only 11 percent needed an ED visit or hospital admission in each year.

Looking at hospitalisation alone showed an even greater risk reduction, from around seven percent per year to less than 3 percent.

"Bariatric surgery is a costly procedure that carries its own risk factors that may offset the benefits regarding the risk of asthma exacerbation for some patients," Hasegawa added.

"To decrease asthma-related adverse events in the millions of obese individuals with asthma, we probably will need to develop safe, effective non-surgical approaches to achieve major weight loss," Hasegawa said.

The study appeared online in the Journal of Allergy and Clinical Immunology.