Randomized placebo-controlled crossover trial of continuous positive airway pressure for mild sleep apnea/hypopnea syndrome

The minimal disease severity at which patients with the sleep apnea/hypopne a syndrome (SAHS) gain benefit from treatment is not well characterized, al though a pilot study of continuous positive airway pressure (CPAP) therapy showed daytime improvements in patients with 5 to 15 apneas + hypopneas per hour slept (AHI). We have thus performed a second, larger, randomized, pla cebo-controlled study in a prospective series of 34 patients (13 female) wi th mild SAHS (AHI 5 to 15) and daytime sleepiness. Patients spent 4 wk on C PAP treatment and 4 wk on an oral placebo, with randomization of treatment order, and daytime assessments on the last day of each treatment. Effective CPAP use averaged 2.8 +/- 2.1 h (mean +/- SD) per night. Compared with pla cebo, CPAP improved symptom score (p < 0.01), subjective (Epworth; p < 0.01 ) but not objective (maintenance of wakefulness test; p > 0.2) sleepiness, performances on 2 of 7 cognitive tasks (p < 0.02), depression score (p < 0. 01), and five subscales of the SF-36 health/functional status questionnaire (p less than or equal to 0.03). Fourteen of 34 patients preferred CPAP. In 14 patients with AHI in the range 5 to 10, symptoms, cognitive function, p sychological well-being and quality of life were improved. These results co nfirm benefits for daytime function after CPAP treatment for mild SAHS, but highlight unacceptability of CPAP in many such patients.