Do obstructive sleep apnea syndrome patients underestimate their daytime symptoms before continuous positive airway pressure treatment?

BACKGROUND

Daytime somnolence is an important feature of the obstructive sleep apnea (OSA) hypopnea syndrome and is usually subjectively assessed using the Epworth Sleepiness Scale (ESS).

OBJECTIVE

To compare the scores of the ESS and different domains of the Quebec Sleep Questionnaire (QSQ) assessed before and after the first months of continuous positive airway pressure (CPAP) treatment, as well as retrospectively without treatment.

METHODS

The ESS score and domain scores of the QSQ were obtained before and after a three-month period of CPAP treatment using a retrospective assessment of the pretreatment scores in 76 untreated OSA patients.

RESULTS

Fifty-two patients completed the study. The ESS and QSQ scores significantly improved following CPAP therapy. Retrospective evaluation of the ESS score was significantly worse than pre- and post-treatment values (mean [± SD] pretreatment score 11.0±4.8; retrospective pretreatment score 13.5±5.1). Such differences were not observed in any domain of the QSQ, including the domain assessing hypersomnolence.

CONCLUSION

OSA patients underestimated their sleepiness according to the most widely used instrument to assess hypersomnolence. This finding may not be observed with other methods used to assess OSA-related symptoms such as quality of life questionnaires.