Background: The sleep apnea-hypopnea syndrome is defined by a pathologic number of respiratory events during sleep (the apnea-hypopnea index, defined as the number of apnea and hypopnea episodes per hour) and daytime symptoms (mostly, excessive sleepiness). In patients with the sleep apnea syndrome, treatment with continuous positive airway pressure (CPAP) normalizes both the apnea-hypopnea index and diurnal symptoms. However, the effect of CPAP in persons with a pathologic apnea-hypopnea index without daytime sleepiness is unclear.
Objective: To investigate the short-term effects of CPAP on quality of life, objective sleepiness, cognitive function, and arterial blood pressure in nonsleepy patients with a pathologic apnea-hypopnea index.
Design: Multicenter randomized, placebo-controlled, parallel-group study.
Setting: Six teaching hospitals in Spain.
Patients: 55 patients with an apnea-hypopnea index of 30 or greater who did not have daytime sleepiness (Epworth Sleepiness Scale score </= 10).
Intervention: Patients were randomly assigned to receive optimal (n = 29) or sham (n = 25) CPAP and were observed for 6 weeks.
Measurements: Quality of life, objective sleepiness (Multiple Sleep Latency Test score), cognitive function, and arterial blood pressure.
Results: The intervention and control groups were similar in terms of mean (+/-SE) age (54 +/- 2 vs. 52 +/- 2 years), apnea-hypopnea index (54 +/- 3 vs. 57 +/- 4), Epworth Sleepiness Scale score (7.0 +/- 0.4 vs. 7.0 +/- 0.4) and adherence to CPAP treatment (5.0 +/- 0.4 vs. 4.0 +/- 0.5 hours/d). Other variables, such as quality of life, cognitive function, and arterial blood pressure, were also similar in both groups before treatment. After 6 weeks of CPAP or sham CPAP, none of these variables changed significantly.
Conclusion: In patients with an apnea-hypopnea index of 30 or greater and no subjective daytime sleepiness, CPAP does not modify quality of life, objective sleepiness, vigilance, attention, memory, information processing, visuomotor coordination, or arterial blood pressure. Treatment with CPAP is therefore not indicated in nonsleepy patients with a pathologic apnea-hypopnea index.