Sleep apnea-hypopnea syndrome, an abnormal frequency of episodes of cessation or slowing of breathing during sleep, usually includes daytime sleepiness. Nasal continuous positive airway pressure (CPAP) is the most common treatment, resulting in less daytime sleepiness and improved quality of life. Many patients with sleep apnea-hypopnea, however, do not have daytime sleepiness. The usefulness of treatment with CPAP in these patients is less clear. Barbé and associates conducted a multicenter, randomized, placebo-controlled study to examine the short-term effects of CPAP on patients with sleep apnea-hypopnea syndrome who were not sleepy during the day.

Fifty-five patients were randomized to receive either optimal nasal CPAP treatment at home or sham CPAP for six weeks. Fifty-four patients completed the study. At baseline and at the end of the treatment period, all patients were evaluated for the following: (1) quality of life, (2) degree of sleepiness, (3) multiple psychologic variables including attention, coordination, and mental control, (4) arterial blood pressure via ambulatory monitoring, and (5) drug and alcohol intake.

After six weeks, no difference in quality of life, subjective and objective sleepiness, or psychologic test results was evident between groups. No significant difference in ambulatory blood pressure changes over time was observed, and few adverse effects of either CPAP or sham CPAP were reported.

The authors conclude that in contrast to the beneficial effects of CPAP in the treatment of patients with sleep apnea-hypopnea syndrome who have daytime sleepiness, there appears to be no short-term beneficial effect of treatment of nonsleepy patients. Because untreated patients may progress to symptomatic sleep apnea-hypopnea syndrome with daytime sleepiness, periodic evaluation is appropriate for patients not treated with CPAP.

In an editorial in the same journal, Pack and Maislin point out that although the major indication for CPAP in patients with sleep apnea-hypopnea syndrome is excessive daytime sleepiness, the relationship of this syndrome to hypertension and, possibly, myocardial infarction and stroke should be considered. It is unclear, however, if CPAP treatment will actually reduce cardiovascular risk. They conclude that only patients with excessive daytime sleepiness require treatment, and that these patients should be reassessed for improvement with CPAP treatment to identify those for whom long-term therapy is appropriate. Tools to measure daytime sleepiness that are more objective than patient self-reporting are being explored.