Longer nightly use of continuous positive airway pressure (CPAP) may help patients with severe obstructive sleep apnea (OSA) achieve normal daily functioning, according to a report in the June 1st issue of SLEEP. Still, the optimal duration of use depends on the outcome being evaluated.

"The actual need for CPAP in terms of reversing sleepiness is likely to be individually determined," lead author Dr. Terri E. Weaver, from the University of Pennsylvania in Philadelphia, said in a statement.

"We cannot assume that an individual using CPAP only four hours per night is inadequately treated for sleepiness outcomes. We also cannot assume that the patient is effectively treated," Dr. Weaver noted. "Therefore, it is important to evaluate treatment effectiveness by assessing the level of adherence in conjunction with treatment outcomes."

The study involved 149 patients with severe OSA who underwent sleepiness and functional testing before and after being treated with CPAP for 3 months.

The likelihood of achieving a normal score on the Epworth Sleepiness Scale increased with up to 4 hours of CPAP; for the Multiple Sleep Latency Test, up to 6 hours of CPAP were required. Normalization of scores on the Functional Outcomes associated with Sleepiness Questionnaire was associated with up to 7.5 hours of CPAP.

The results suggest that the odds of normal daily functioning generally increases with longer durations of CPAP use, the authors state. However, it should be noted that some patients achieve normal functioning with relatively limited use of this modality, they add.

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