Bariatric surgery appears to cut risks for serious asthma-related events

A study led by Massachusetts General Hospital (MGH) investigators suggests that bariatric surgery can significantly reduce the risk of asthma attacks - also called exacerbations - in obese patients with asthma. Their report, published online in the Journal of Allergy and Clinical Immunology, is the first to find that significant weight reduction can reduce serious asthma-associated events.

"We found that, in obese patients with asthma, the risk of emergency department visits and hospitalizations for asthma exacerbations decreased by half in the two years after bariatric surgery," says Kohei Hasegawa, MD, MPH, MGH Department of Emergency Medicine, the lead author of the study. "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."

Both obesity and asthma are serious public health problems at historically high levels in the U.S., the authors note, and many researchers have associated obesity with the development of asthma and with an increased risk for asthma exacerbations. While previous studies investigating whether weight loss could reduce asthma risks showed little or no benefit, participants in those studies lost only modest amounts of weight. The current study was designed to investigate whether bariatric surgery - regarded as the most effective option for morbidly obese patients - might have a greater effect on asthma-associated risks.

Using available databases reflecting the utilization of health services in California, Florida and Nebraska - all three of which give access to deidentified information on individual patients - the research team 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.

This design, in which participants essentially act as their own controls, reduces the need to control for additional factors - such as age, gender, genetic background and physical activity - that might bias the results.

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 hospitalization alone showed an even greater risk reduction, from around 7 percent per year to less than 3 percent. A comparison with patients who had other types of abdominal surgery showed that non-bariatric procedures had no impact on asthma exacerbation risk.

Asthma and Obesity Obesity is on the rise in the United States. It’s well known that obesity can cause diabetes and heart disease, but studies show that it also leads to higher rates of asthma. Asthma is already a very common disease, but obese people are at an even higher risk. In Michigan, 13% of obese adults say they have asthma, but only 8% of non-obese adults say they have asthma.