Randomized Placebo-controlled Crossover Trial of Continuous Positive Airway Pressure for Mild Sleep Apnea/Hypopnea Syndrome

TLDR

The benefit threshold for treating mild sleep apnea/hypopnea syndrome (AHI 5–15) remains unclear, though a pilot CPAP study suggested daytime improvements in this group. We conducted a 4‑week, randomized, placebo‑controlled crossover trial with 34 mild SAHS patients, comparing CPAP to an oral placebo and assessing daytime outcomes at each treatment’s end. CPAP yielded significant improvements in symptom scores, subjective sleepiness, certain cognitive tasks, depression, and quality‑of‑life subscales, with 14 of 34 patients preferring it and those with AHI 5–10 showing enhanced daytime function, yet many patients found CPAP unacceptable.

Abstract

The minimal disease severity at which patients with the sleep apnea/hypopnea syndrome (SAHS) gain benefit from treatment is not well characterized, although 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, placebo- controlled study in a prospective series of 34 patients (13 female) with mild SAHS (AHI 5 to 15) and daytime sleepiness. Patients spent 4 wk on CPAP 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 placebo, 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 ⩽ 0.03). Fourteen of 34 patients preferred CPAP. In 14 patients with AHI in the range 5 to 10, symptoms, cognitive function, psychological well-being and quality of life were improved. These results confirm benefits for daytime function after CPAP treatment for mild SAHS, but highlight unacceptability of CPAP in many such patients.