Adaptation of the 10-Item Functional Outcomes of Sleep Questionnaire to Iranian Patients with Obstructive Sleep Apnea

The purpose of this study was to evaluate the psychometric properties of the Farsi version of 10-item Functional Outcomes of Sleep Questionnaire (FOSQ-10) in Iranian patients with obstructive sleep apnea (OSA).

The FOSQ-10 was translated into Farsi using the standard forward–backward method. One hundred patients who fulfilled the inclusion criteria completed a series of questionnaires including IR-FOSQ-10, Medical Outcome Survey Short Form 12 (SF-12) and Epworth Sleepiness Scale (ESS). Internal consistency, test–retest reliability, concurrent validity, discriminant validity and responsiveness of IR-FOSQ-10 were investigated.

The Cronbach’s alpha coefficient was 0.85 in IR-FOSQ-10 total score and ranged from 0.78 to 0.83 in each subscale. The test–retest reliability demonstrated by intraclass coefficient was 0.92. There were significant moderate-to-good negative correlations between IR-FOSQ-10 subscales and ESS except for sexual relationship subscale. FOSQ-10 subscales generally correlated higher with related subscales of SF-12. The IR-FOSQ-10 was able to distinguish patients with abnormal sleepiness score from those with normal sleepiness score. The results of sensitivity to change proved that the IR-FOSQ-10 was able to detect changes after continuous positive airway pressure therapy.

The psychometric properties of the IR-FOSQ-10 suggest that it is a reliable and valid measure among Iranian patients with OSA.