Long-term use of continuous positive airway pressure (CPAP) was associated with higher self-reported physical activity levels in adults with co-occurring obstructive sleep apnea (OSA) and cardiovascular disease (CVD), in new research.
“The aim of this study was to determine whether long-term CPAP treatment affects self-reported physical activity among participants with moderate-severe OSA and comorbid CV disease,” wrote David Stevens, PhD, of Flinders University, Adelaide, Australia, and his colleagues. The findings were recently published in the Journal of Clinical Sleep Medicine.
Researchers conducted a secondary analysis of the Sleep apnea cardiovascular endpoints (SAVE) trial that enrolled 2,687 adults aged 45-75 years old with OSA and confirmed CVD. In the study, participants were randomized to receive either CPAP plus usual care or usual care alone.
Physical activity levels were self-reported using the Leisure-Time Exercise Questionnaire (LTEQ) at baseline and at 6-, 24-, and 48-month follow-up intervals. The physical functioning subscale of the 36-item short form questionnaire (SF-36) was used to determine if activity levels were consistent with expert recommendations and to evaluate the effects on any self-perceived limitation of physical activity.
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Moderate Physical Activity Was Higher Among CPAP Users
After a mean follow-up duration of 3.7 years, participants in the CPAP arm had approximately 20% higher levels of moderate physical activity, compared with the control arm (adjusted mean scores]: 8.7 points vs. 7.3 points; 95% confidence interval, 7.5-9.9 vs. 6.1-8.5; P = .003).
However, no significant difference was observed between treatment arms for mild physical activity (adjusted mean scores, 14.4 points vs. 14.2 points; 95% CI, 13.5-15.3 vs. 13.3-15.1; P = 0.599) or vigorous physical activity (adjusted mean scores, 3.4 points vs. 2.9 points; 95% CI 2.6-4.2 vs. 2.1-3.7; P = .125).
In addition, participants in the CPAP group reported less limitation in physical activity (adjusted between-group difference in SF-36 physical functioning subscale score = 1.66; 95% CI, 0.87-2.45; P < .001) and were more likely to report activity levels consistent with guideline recommendations.
“We were pleasantly surprised to find that people assigned to CPAP reported more physical activity than their counterparts who received usual care, despite being given no specific exercise instructions,” Kelly A. Loffler, PhD, a coauthor of the study, said in an interview.
“While I don’t think this will result in any immediate changes to guidelines, it is a helpful reminder to clinicians who are treating such patients, that the symptomatic benefits people experience with CPAP present a window of opportunity to improve health more holistically,” Loffler explained.
The researchers acknowledged that a key limitation of the study was the use of self-reported outcome measures. In future studies, they recommended that recent technological innovations, such as the availability of activity tracking devices, should be used to measure physical activity.
They also noted that patients with excessive sleepiness and severe hypoxemia were excluded from the SAVE trial; thus, the findings may not be generalizable to all patients.
Study Reinforces CPAP’s Health Benefits
Emerson M. Wickwire, PhD, associate professor of psychiatry and medicine at the University of Maryland, Baltimore, explained that CPAP treatment is associated with well-documented health benefits among patients with CVD, as well as enhanced quality of life.
“These results provide further evidence that treating OSA can provide direct and indirect health benefits, suggesting that increased physical activity can be a vital pathway to improved cardiovascular health and enjoyment of life,” Wickwire, who is also director of the Insomnia Program at the University of Maryland Midtown Medical Center, Baltimore, said in an interview.
Steven M. Scharf, MD, a pulmonologist who is director of the Sleep Disorders Center (Adults) at the University of Maryland, also said the study findings were consistent with previous research involving patients treated for OSA.
“It is no surprise that treatment of OSA improves patient’s daily physical functioning,” explained Scharf, who is also a clinical professor, in an interview. “These results are expected, but very welcome, and I was glad to see them.”
The study was funded by the National Health and Medical Research Council of Australia, the Respironics Sleep and Respiratory Research Foundation, and Philips Respironics. Some authors reported financial affiliations with medical device and pharmaceutical companies. Loffler, Wickwire, and Scharf reported no conflicts of interest related to this work.