Bariatric surgery no cure for sleep apnea

MONASH U. (AUS) — Bariatric surgery may improve chances of losing weight, but appears to have limited success treating obstructive sleep apnea.

Obstructive sleep apnea (OSA) is a condition affecting almost five percent of the Australian population, in which a person stops breathing for periods of time during their normal sleep cycle.

The condition is caused by upper airway obstruction due to a floppiness or heaviness around the face and neck. In some patients, obesity is thought to be a significant factor.

For the study, published in the Journal of the American Medical Association, participants were recruited from sleep centers where they had been recently diagnosed with moderate to severe OSA. All had a body mass index of between 35 and 55. Both groups—surgical and conventional weight loss—were followed up every four to six weeks for two years.

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The participants who had laparoscopic adjustable gastric banding (LAGB) achieved an average two-year weight loss of approximately 20 percent of their initial weight. The conventional group, who were provided with tailored dietary, exercise, and behavioral programs, lost on average almost three percent of their body weight over the two-year period.

But the dramatic differences in weight loss were not reflected in improvements in their sleep apnea, which was comprehensively monitored using polysomnography, says John Dixon, associate professor and head of obesity research at Monash University.

“Both groups experienced a reduction in OSA severity, but the difference between the surgical group and the conventional group was surprisingly small, given the weight loss disparity, and the majority still needed their CPAP machines during sleep.

“Our research confirmed that weight loss is associated with reduction in OSA, but it’s a complex relationship. The effects vary greatly between individuals. It seems that the largest improvement in OSA, is associated with mild to moderate, rather than extreme weight loss.”

The researchers urged caution in advising patients on the benefits of weight loss for sleep apnea reduction and suggest that OSA therapies should be continued until the patient is properly assessed.

Source: Monash University