OBJECTIVE: The study is to evaluate reliability and validity of the short Thai version of Functional Outcome of Sleep Questionnaire (FOSQ-10T), in patients with sleep disordered breathing (SDB).
METHODS: Inclusion criteria were Thai patients with SDB age ≥ 18 years old who had polysomnography results available. Exclusion criteria were patients unable to complete questionnaire for any reason, patients with a history of continuous antidepressant or alcohol use, and underlying disorders including unstable cardiovascular, pulmonary, or neurological conditions. All participants were asked to complete the FOSQ-10 T and Epworth sleepiness scales (ESS). Of these, 38 patients were required to retake FOSQ-10 T at 2-4 weeks later to assess test-retest reliability, and 19 OSA patients treated with CPAP were asked to do so at 4 weeks following therapy to assess questionnaire\'s responsiveness to treatment.
RESULTS: There were 42 participants (24 men, 18 women), with a mean age of 48.3 years. The internal consistency of the FOSQ-10T was good, as indicated by Cronbach\'s alpha coefficient of 0.85. The test-retest reliability was good, as indicated by intraclass correlation coefficient of 0.77. The correlation between the FOSQ-10T and ESS scores (concurrent validity) was moderate (r =  - 0.41). The scores of FOSQ-10T significantly increased after receiving adequate CPAP therapy, showing an excellent responsiveness to treatment. However, there was no significant association between FOSQ-10T scores and OSA severity measured by apnea-hypopnea index.
CONCLUSIONS: The FOSQ-10T has good reliability and validity to use as a tool to assess QOL in Thai patients with SDB. It is convenient and potentially useful in both clinical and research settings.

It is unclear if the response to positive airway pressure (PAP) treatment is different between African American (AA) and European Americans (EA). We examined whether race modifies the effects of PAP on sleep and daytime function. We assessed Epworth Sleepiness Scale (ESS), Functional Outcomes of Sleep Questionnaire, Psychomotor Vigilance Task and actigraphy in 185 participants with moderate-to-severe obstructive sleep apnea before and 3-4 months after PAP treatment. The participants were middle-aged (mean, 55.1 years), 83.8% men and 60.5% AA. Linear regression models were used to examine the effect of race on outcomes. The AA had smaller reductions in ESS (mean change (95% confidence interval, CI) AA, -2.30 [-3.35, -1.25] vs. EA, -4.16 [-5.48, -2.84] and frequency of awakenings (AA, -0.73 [-4.92, 3.47] vs. EA, -9.35 [-15.20, -3.51]). A race × PAP usage interaction term was added to the model to examine if the change in outcomes per 1 h increase in PAP usage differed by race. AA exhibited greater improvement in wake after sleep onset (β (95% CI) AA, -8.89 [-16.40, -1.37] vs. EA, 2.49 [-4.15, 9.12]) and frequency of awakening (β (95% CI) AA, -2.59 [-4.44, -0.75] vs. EA, 1.71 [-1.08, 4.50]). The results indicate the importance of race in evaluating outcomes following PAP treatment.