Study objectives: To compare compliance and treatment response between continuous positive airway pressure (CPAP) and auto-titrating positive airway pressure (APAP) and to develop selection criteria for the use of APAP.
Design: Randomized, single-blinded, parallel crossover study.
Setting: Tertiary referral sleep disorders center.
Patients: Consecutive patients with obstructive sleep apnea syndrome requiring treatment with CPAP.
Interventions: 2-month treatment each of conventional CPAP and APAP in random order comparing objective compliance, Epworth Sleepiness Score, SF-36 Health Survey, visual-analog measures of ease of and attitude to treatment, side effects, and treatment pressures or system leaks obtained from the Autoset T device.
Measurements and results: There were no differences between treatment modes in overall compliance (CPAP 4.86 +/- 2.65, APAP 5.05 +/- 2.38 hours per night, P = .14), Epworth Sleepiness Scale scores (baseline 12.4 +/- 5.1, CPAP 8.4 +/- 5.2, APAP 7.9 +/- 4.8, P < .001 relative to baseline, NS between modes), SF-36 scores (significant improvements in Role Physical and Vitality domains relative to baseline, P < .001 but NS between modes). There were fewer reported side effects in APAP mode (CPAP 28, APAP 15 reports, P = .02) and compliance was greater with APAP in those reporting any side effect (95% confidence interval CPAP 0-6.8, APAP 2.9-7.8 hours per night, P < .001). APAP delivered significantly lower median and 95th centile airway pressures and fewer system leaks.
Conclusions: Compliance, subjective sleepiness, and quality of life are similar between patients who used CPAP and APAP. APAP delivers lower pressures and results in lower-pressure leaks and fewer reported side effects. Compliance is higher with APAP in subjects reporting any side effect. APAP may be indicated in patients reporting side effects with conventional CPAP.