Use of continuous positive airway pressure (CPAP) treatment boosts energy and cuts down on daytime sleepiness among obstructive sleep apnea patients — at least over the short term — according to results of a small randomized trial.
The trial of 59 OSA patients resulted in a significant drop in fatigue and increased energy after three weeks of active CPAP treatment compared with placebo CPAP lacking the positive inhalation pressure to keep airways open during sleep (both P<0.05), reported Lianne M. Tomfohr, MS, of the joint doctoral program of San Diego State University and the University of California San Diego, and colleagues.
In fact, the symptom improvement was substantial enough to move patients out of the clinically significant range for level of fatigue, Tomfohr’s group wrote in the Jan. 1 issue of Sleep.
Excessive daytime sleepiness that causes patients to fall asleep during common situations and lack of energy are two common complaints among people with OSA — a disorder that affects 3% to 7% of the population, the authors noted.
However, randomized trials hadn’t shown any more than a placebo effect from short-term CPAP use, despite clear reductions in oxygen desaturation during the night, according to background provided by the researchers.
So Tomfohr and her colleagues randomized 59 patients with previously untreated moderately-severe OSA to conventional CPAP or a double-blind placebo device. The placebo device used the same CPAP machine, but with its mask modified to allow free flow of room air, providing a masking breeze at the nose but not the extra air pressure needed during inhalation to keep collapsed airway tissues open during sleep and supply needed oxygen.
Trial participants were overwhelmingly male and white, ranging in age from 29 to 50, with an average body mass index (BMI) of 30.
As expected, the therapeutic CPAP cut the apnea-hypopnea index from a mean of 38.64 at baseline to 24.28 episodes per hour at three weeks (P<0.01). The placebo group saw a nonsignificant drop from 31.67 to 25.93 per hour (P=0.31).
Fatigue essentially disappeared with therapeutic CPAP, with total self-reported scores averaging -0.10 at the end of the study compared with 8.76 at baseline on the Multidimensional Fatigue Symptom Inventory — Short Form. The control group showed a slight placebo effect, with total fatigue scores falling from 5.77 to 4.20, which was nonsignificant at P>0.36. The difference between groups was significant at P=0.02.
Patients’ energy level measured with the vigor-activity subscale of the Profile of Mood States — Short Form showed a similar pattern, with improvement from 7.17 to 4.03 with CPAP and 6.27 to 5.77 with placebo over the study period, which again differed significantly between groups (P=0.03).
Sleepiness wasn’t impacted overall, but those with excessive sleepiness marked by a score of 9 or greater on the Epworth Sleepiness Scale questionnaire did see an improvement in scores with therapeutic CPAP compared with placebo CPAP on all three scales (all P<0.05).
Since longer-term studies have supported large improvements in sleepiness with CPAP, a longer duration of treatment than the three weeks used in the trial or a higher proportion of excessively sleepy patients may have been needed to find a significant effect on this measure, Tomfohr’s group suggested.
The relatively short treatment period may have been another limitation of the study, the researchers acknowledged, along with a study population free of comorbidities (e.g., a history of heart, liver, renal, cerebrovascular disease or diabetes), which may not reflect typical patients seen at a sleep medicine center.
But the investigators noted that compliance was good in both the intervention and control groups, although the placebo group used the sham CPAP machine for more hours a night.
The mechanism for the reduction in fatigue observed in the study was not clear, but the researchers suggested that it may involve a reduction in upper airway and systemic inflammation.
The study was supported by the National Institutes of Health through the National Heart, Lung, and Blood Institute; National Institute on Aging; and National Center for Research Resources.
Tomfohr reported having no conflicts of interest to disclose.
One coauthor reported consulting or serving on the advisory board or both for Ferring Pharmaceuticals, GlaxoSmithKline, Merck, NeuroVigil, Neurocrine, Pfizer, Respironics, Sanofi-Aventis, Sepracor, and Schering-Plough, as well as research support form Sepracor and Litebook. A second coauthor reported researcher support from Sepracor.