Effect of continuous positive airway pressure on sleep architecture in thesleep apnea-hypopnea syndrome - A randomized controlled trial

There is randomized controlled evidence that patients with sleep apnea-hypo pnea syndrome (SAHS) treated with continuous positive airway pressure (CPAP ) have improved daytime function and quality of life. "Before-and-after" da ta indicate that CPAP improves sleep quality, but there is no randomized co ntrolled evidence of this. We tested the hypothesis that CPAP improved slee p quality in patients with SAHS. We also sought correlations between polyso mnographic (PSG) indices and benefit from use of CPAP. Twenty-two patients with SAHS (median, [interquartile range] apnea-hypopnea index, 40 [25-65] e vents/h) spent 1 mo receiving CPAP and 1 mo receiving placebo capsules, in random order, and home sleep studies were performed at the end of each mont h. CPAP resulted in a lower arousal index, less Stage 1, and more Stage 3+4 sleep, but there was no increase in Stage REM (rapid eye movement) sleep. Improvement in Epworth score after 6-12 mo of treatment correlated signific antly with PSG indices on CPAP: sleep efficiency index (r = 0.78, p < 0.001 ), Stage REM (r = 0.55, p = 0.001), Stage 3+4 (r = 0.5, p = 0.02), and arou sal index (r = -0.43, p = 0.05). This study provides randomized controlled trial evidence that patients with SAHS sleep better when receiving CPAP. Pa tients with good sleep quality on CPAP at 1 mo are likely to gain later ben efit in subjective daytime sleepiness.