Sleep Apnea Risk Swells With Asthma

Persons who have asthma appear to be at increased risk for new-onset obstructive sleep apnea (OSA), according to a new study.

“This study prospectively examined the relationship of asthma with OSA assessed with laboratory-based polysomnography and found that preexistent asthma was a risk factor for the development of clinically relevant OSA in adulthood over a 4-year period. Furthermore, the asthma-OSA association was significantly dose-dependent on duration of asthma,” wrote the authors, led by Mihaela Teodorescu, MD, MS, of the William S. Middleton Memorial Veteran’s Hospital and the University of Wisconsin School of Medicine and Public Health in Madison.

OSA is common and becoming increasingly prevalent among adults with asthma, adversely affecting health and leading to a higher risk of death. Cross-sectional studies have suggested an association between asthma and OSA. This study examined the prospective relationship of asthma with incident OSA.

Dr Teodorescu and colleagues used data from the Wisconsin Sleep Cohort Study, a population-based prospective epidemiologic study that included randomly selected adult employees of state agencies, aged 30 to 60 years, in 1988. The patients were recruited to attend overnight polysomnography and fill out health-related questionnaires about every 4 years. Eligible participants were identified as free of OSA at study entry by 2 baseline polysomnography studies.

Slightly more than one-fourth of the 81 participants (27%) with asthma experienced incident OSA over their first observed 4-year follow-up intervals. This compared with 75 of 466 participants (16%) without asthma. With the use of all available 4-year intervals, including multiple 4-year interval observations per participant, those with asthma experienced 45 incident OSA cases during 167 4-year intervals (27%) and those without asthma experienced 160 incident OSA cases during 938 4-year intervals (17%).

The risk of new OSA was increased nearly 40% in participants with preexisting asthma compared with those without asthma after the investigators controlled for sex, age, and baseline and change in body mass index-all factors known to contribute to sleep apnea.

The researchers asked the participants, “Do you have feelings of excessive daytime sleepiness?” to help determine habitual sleepiness. Asthma duration was related to both new OSA and new OSA with habitual sleepiness, defined as answering “often” (5 to 15 times a month) and “almost always” (more than 15 times a month).

“Studies investigating the mechanisms underlying this association and the value of periodic OSA evaluation in patients with asthma are warranted,” the researchers stated.

If these results are confirmed in a larger study with more asthma cases, the finding would have important clinical relevance, they suggested.

Dr Teodorescu recommends that primary care physicians “look for OSA symptoms among asthma patients. The literature suggests that OSA worsens asthma. Treatment for OSA improves asthma symptoms during the day and night, as well as quality of life and lung function measures. If you identify and treat OSA, the hope is that asthma control will improve.”

The researchers published their results in the January 13, 2015, issue of JAMA.