ASSESSMENT OF THE VALIDITY AND UTILITY OF A SLEEP-SYMPTOM QUESTIONNAIRE

Although questionnaires have been developed to assess symptoms of obst ructive sleep apnea (OSA), their overall reliability and utility have not been established. We have evaluated the ability of a questionnaire to identify increased apnea activity (IAA) in 465 participants in an epidemiologic study of OSA. Subjects and their roommates each complete d a questionnaire and underwent in-home sleep studies. Responses to 56 questions about sleep habits, sleepiness, and daytime performance wer e analyzed with factor analysis, logistic regression, and receiver-ope rator curves (ROCs). Factor analysis demonstrated that 16 questions, g rouped into five factors (functional impact of sleepiness, self-report ed breathing disturbances, roommate-observed breathing disturbances, d riving impairment, and insomnia) explained 67% of the variance in the questionnaire data. Symptom questions demonstrated internal consistenc y (Cronbach correlations: 0.91 to 0.98). Moderate levels of agreement were observed between self- and roommate-reported responses for nine o f ten questions asked of both the subject and his/her partner (kappa s tatistics: 0.34 to 0.57). Logistic regression analysis demonstrated th at IAA could be best predicted by three questions about intensity of s noring, roommate-observed choking, and having fallen asleep while driv ing (ROC area: 0.78). Use of symptoms with data on gender and body mas s index (BMI) improved predictive ability by 10% (ROC area: 0.87). Thu s, questionnaire data provide a valid means of characterizing symptom distributions in population surveys of OSA. Predictive ability is not significantly improved with multiple questions or a separate roommate questionnaire, but is improved with consideration of data on BMI and g ender.