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Longitudinal comparison study of pressure relief (C-Flex™) vs. CPAP in OSA patients



Continuous positive airway pressure (CPAP) devices with the option of flexible pressure delivery (e.g., C-Flex) are thought to provide an improved degree of comfort and result in better therapeutic adherence while maintaining standard CPAP efficacy. The purpose of this study was to compare adherence and subjective measures of comfort between C-Flex and CPAP treatment.


The study was an international, multisite, single-blinded study with participants randomized to either C-Flex or CPAP. Participants completed subjective measures of sleepiness and comfort at baseline, and at 30-, 90-, and 180-day follow-ups. Additionally, compliance data were downloaded from the device at each follow-up. Repeated measures analysis of variance was used to assess the effects of treatment.


There were 138 men and 46 women (average age of 48 ± 9.2, average Epworth Sleepiness Scale score of 14.9 ± 3.6, and average diagnostic apnea/hypopnea index (AHI) of 51.9 ± 27.7). C-Flex and CPAP groups were comparable on baseline measures, achieved comparable AHI on titration, and had comparable PAP pressure requirements. C-Flex users had comparable average hours of use per night and total nights of use across the study, but had a trend (p < .07) toward achieving greater total hours of utilization. While both groups had comparable decreases in sleepiness, C-Flex users reported on visual analog scales greater comfort (64.3 vs. 57.4; p = .01).


The results of this study demonstrated that C-Flex has comparable resolution of respiratory indices and adherence. Furthermore, C-Flex users reported greater mask comfort.

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This study was funded by Respironics, Inc.

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Correspondence to Leon Rosenthal.

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Dolan, D.C., Okonkwo, R., Gfullner, F. et al. Longitudinal comparison study of pressure relief (C-Flex™) vs. CPAP in OSA patients. Sleep Breath 13, 73–77 (2009).

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