Positive airway pressure initiation: a randomized controlled trial to assess the impact of therapy mode and titration process on efficacy, adherence, and outcomes

Abstract

Study objectives: (1) To determine the efficacy of automatically adjusted positive airway pressure (APAP) with a comfort feature (A-Flex) at reducing apneas and hypopneas in participants with moderate to severe OSA. (2) To determine the relative difference between A-Flex, continuous positive airway pressure (CPAP), and APAP-derived optimal pressure for CPAP (CPAP(APAP)) on adherence to treatment. (3) To determine the relative difference between APAP with A-Flex, CPAP, and CPAP(APAP) on long-term change in functional outcomes.

Design: Randomized, double-blinded, 3-arm, multicenter trial.

Setting: University and Veterans Affairs medical centers.

Patients or participants: 168 participants were randomized, and 140 completed the 180-day study.

Interventions: (1) A-Flex; (2) CPAP; (3) APAP for 14 days and then switched to CPAP at a fixed pressure.

Measurements and results: Apnea-hypopnea indices, average and minimum oxygen saturation, time spent < 90% were significantly poorer for A-Flex vs. CPAP at the initiation of study treatment; with the exception of minimum oxygen saturation, these differences were absent at 180 days. A-Flex had lower average leak values at both 3 and 6 months. There were no significant differences between groups in major efficacy, adherence, and outcome (subjective sleepiness, objective vigilance, blood pressure, quality of life) measures. No differences between groups in attitudes toward use were observed at 3 or 6 months; participant ratings for CPAP were significantly higher than A-Flex on treatment satisfaction and benefit, but not different for sleep quality and mask comfort.

Conclusions: We found that A-Flex shows equivalency, but non-superiority (except for average leak values), in efficacy, adherence, and functional outcomes compared to CPAP after either 3 or 6 months.

Clinical trial registry: Positive Pressure Treatment of Obstructive Sleep Apnea, http://www.clinicaltrials.gov, NCT00636181.

Keywords: A-Flex; APAP; Auto-CPAP; CPAP; automatically adjusted positive airway pressure; obstructive sleep apnea.

Figure 1

Automatically adjusted positive airway pressure (APAP) algorithm with A-Flex. Pressure (solid line in upper part of figure) is automatically adjusted by the APAP device, with the pressure reduced at the start through the end of exhalation, with the pressure returning to the therapeutic level at the start of the next inspiratory phase. The amount of pressure reduction can be adjusted (gray lines).

Figure 2

Participant flowchart. AM, anthropometric measurements; APAP, Auto-CPAP; ATEA, Adherence and Therapy Effectiveness Assessment; ATUQ, Attitudes Toward Use Questionnaire; CPAP, continuous positive airway pressure; ESS, Epworth Sleepiness Scale; FOSQ, Functional Outcomes of Sleep Questionnaire; PAP, positive airway pressure; PSG, polysomnography; PVT, psychomotor vigilance task; VAS, visual analog scales; VS, vital signs.