When asthmatics sleep, many of them continue to struggle with breathing -- and an understanding of their sleep-related problems may help doctors better diagnose and treat their patients’ asthma, according to new University of Michigan Health System ( UMHS ) research.

Symptoms of sleep apnea and other breathing problems during sleep are common among people with asthma.

Researchers examined the connection between sleep-related breathing disorders by giving questionnaires to patients with asthma.
Of the 115 subjects included in the study so far, most were in one of the most severe stages of asthma.

Most participants were being treated for asthma with inhalers and other medications, but they were still symptomatic, says Mihaela Teodorescu, at UMHS.

Large percentages of the people included in the study – 33 percent of men and 49 percent of women – were found to be at risk for obstructive sleep apnea.

Those numbers are based on the symptoms of sleep apnea reported by the subjects, including 86 percent who said they snored with any frequency, 38 percent who snored regularly and 31 percent who said a family member had witnessed their pauses in breathing during sleep.
The symptoms of sleep apnea were related to the severity of asthma, independent of other conditions that could influence asthma.
In addition, 55 percent of these people said they experienced excessive daytime sleepiness.

Although the study is still ongoing, Teodorescu says the early findings should encourage doctors to consider sleep apnea as a possible aggravating condition in their asthma patients.

These early findings offer one more reason people should be tested for sleep disorders, a vast majority of which are under-diagnosed, says Ronald Chervin, director of the Sleep Disorders Center and Michael S. Aldrich Sleep Disorders Laboratory at UMHS.
Some 80 percent of men and 90 percent of women who have sleep apnea don’t know it, he says.

“We might be able to control some of these patients’ asthma better if we could identify and treat their apnea,” says Chervin, at University of Michigan - Medical School.

He also notes that many asthmatics complain of daytime sleepiness, which is often assumed to be a result of the asthma itself.
Instead, the study is finding that apnea symptoms rather than asthma severity best predict daytime sleepiness. The investigators hope that attention to the overlap of sleep apnea and asthma might one day lead to better nighttime sleep and daytime alertness for asthmatics.

The study was funded by the National Institutes of Health.

Source: American Thoracic Society’s International Conference, 2005


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