SAN DIEGO, May 21 -- Even in patients with mild obstructive sleep apnea, continuous positive airway pressure (CPAP) improves daily function and reduces daytime sleepiness, a researcher said here.
In a randomized, blinded, sham-controlled trial, use of CPAP also improved mood, according to Terry Weaver, R.N., Ph.D., of the University of Pennsylvania.
The so-called CATNAP trial -- short for CPAP Apnea Treatment North American Program -- offers "compelling evidence" of the benefit of the therapy in those with mild disease, Dr. Weaver told a late-breaking session on clinical trials at the annual meeting of the American Thoracic Society.
Action Points
- Note that this study was presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
Those getting the therapy had "highly significant and clinically important improvements in daily functioning, daytime sleepiness, and mood," Dr. Weaver said.
The issue had been controversial, with earlier studies yielding mixed results, she said.
To clarify the issue, she and her colleagues enrolled 281 patients with an apnea-hypopnea index between five and 30. Data from 223 patients was available for analysis at the end of the study.
The patients were randomized to get CPAP for eight weeks or a sham treatment with machines that looked and sounded like normal ones but actually delivered no pressure.
After the initial eight weeks, those who had been getting the sham CPAP were crossed over and given active therapy for eight weeks, but Dr. Weaver did not report data from that segment of the study.
The main endpoint was change in the Functional Outcomes of Sleep Questionnaire, but the researchers also measured differences on the Epworth Sleepiness Scale and total mood disturbance on the Profile of Mood States (POMS) test.
Analysis showed:
- On the outcomes questionnaire, those in the active arm had an improvement of 0.89 -- from 13.93 to 14.81 -- a difference that was significant at P=0.0001.
- Those in the sham arm had no significant change and the combined effect size was 0.41, which was significant at P=0.006.
- On the Epworth scale (where a lower score is better) those in the active arm saw their scores decrease by 2.46 points, compared with 0.68 for those in the sham arm. The decrease in the active arm was significant at P=0.001, but nonsignificant in the sham arm.
- Total mood disturbance was reduced by 8.9 points on the POMS test for those in the active arm, which was significant at P=0.014. Those in the sham arm had a nonsignificant decrease of 1.7 points.
CPAP "improves quality of life and is an effective therapy in those with milder obstructive sleep apnea," Dr. Weaver said.
CATNAP is "a very important study on a number of fronts," said Lawrence Kline, D.O., of the Scripps Clinic Sleep Center in La Jolla, Calif., who was a discussant for the study.
"There hasn't been a good placebo-controlled trial" among patients with mild disease, Dr. Kline said, but CATNAP was a "very carefully done study."
"This definitely helps awareness that there are some outcome measures that matter than can be improved if you treat them right," he said.
Whether the study changes clinical practice is another matter, he said.
"Behavior in practice is influenced by a lot of factors and evidence is just one element," Dr. Kline said. "Hopefully, this will translate into better care"
| The study was supported by the NIH and Respironics.
Dr. Weaver reported financial links with Protech, Respironics, Cephalon, Apnex Medical, sanofi-aventis, Merck, Sleep Solutions, Organon, Aspire Medical, Ventus, GlaxoSmithKline, and Johnson & Johnson. |