Patients with the sleep apnea/hypopnea syndrome (SAHS) treated by nasal continuous positive airway pressure (CPAP) need to use CPAP long-term to prevent recurrence of symptoms. It is thus important to clarify the level of long-term CPAP use and the factors influencing long-term use. We examined determinants of objective CPAP use in 1, 211 consecutive patients with SAHS who were prescribed a CPAP trial between 1986 and 1997. Prospective CPAP use data were available in 1, 155 (95.4%), with a median follow-up of 22 mo (interquartile range [IQR], 12 to 36 mo). Fifty-two (4.5%) patients refused CPAP treatment (these were more often female and current smokers); 1,103 patients took CPAP home, and during follow-up 20% stopped treatment, primarily because of a lack of benefit. Methods of survival analysis showed that 68% of patients continued treatment at 5 yr. Independent predictors of long-term CPAP use were snoring history, apnea/hypopnea index (AHI), and Epworth score; 86% of patients with Epworth > 10 and an AHI >/= 30 were still using CPAP at 3 yr. Average nightly CPAP use within the first 3 mo was strongly predictive of long-term use. We conclude that long-term CPAP use is related to disease severity and subjective sleepiness and can be predicted within 3 mo.

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

Arterial blood pressure rises at apnea termination, and there is increasing evidence that the sleep apnea-hypopnea syndrome (SAHS) is associated with daytime hypertension but no randomized controlled trial evidence of whether SAHS treatment reduces blood pressure exists. We, therefore, conducted a randomized placebo-controlled cross-over study of the effects of 4 wk of continuous positive airway pressure (CPAP) or oral placebo on 24-h blood pressure in 68 patients (55 males, 13 females; median apnea-hypopnea index [AHI], 35) not receiving hypotensive medication. Ambulatory blood pressure was recorded for the last 48 h of each treatment. Epworth Sleepiness Score (ESS) and Functional Outcomes of Sleep Questionnaire (FOSQ) were also recorded. All patients were normotensive. There was a small decrease in 24-h diastolic blood pressure (placebo, 79.2 [SE 0.9] mm Hg; CPAP, 77.8 [SE 1.0] mm Hg; p = 0.04) with the greatest fall occurring between 2:00 A.M. and 9:59 A.M. The observed decrease in 24-h diastolic blood pressure was greater in two a priori groups, CPAP use > or = 3.5 h per night (81.5 [SE 1.2] mm Hg; 79.6 [SE 1.2] mm Hg; p = 0.03) and those with more than twenty 4% desaturations per hour (82.4 [SE 2.1] mm Hg; 77.4 [SE 2.1] mm Hg; p = 0.002). Systolic pressure also fell in the latter group (133.1 [SE 2.8] mm Hg; 129.1 [SE 2.1] mm Hg; p = 0.009). Desaturation frequency was the best predictor of diastolic blood pressure fall with CPAP (r = 0.38; p = 0.002). Both ESS and FOSQ domains improved. Thus, CPAP can reduce blood pressure in patients with SAHS, particularly in those with nocturnal oxygen desaturation, but the decrease is small.

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