Validation of the Persian version of Berlin sleep questionnaire for diagnosing obstructive sleep apnea

ABSTRACT

Obstructive sleep apnea [OSA] is a common but usually under-diagnosed sleep disorder. Objective diagnosis is based on polysomnography, which is an expensive test. We assessed the reliability and diagnostic accuracy of the Berlin questionnaire [BQ] in diagnosis of OSA in Iranian sleep clinic patients. A cross-sectional linguistic validation study was conducted on consecutive Iranian patients with Persian language attending one sleep clinic in Isfahan [Iran] were studied. Patients completed the Persian BQ [contains 10 questions in 3 categories], developed by forward-backward translation method. The patients underwent an overnight polysomnographic study at the clinic. Apneas/hypopnea index of >5/Hour was considered for diagnosis of OSA. One hundred and fifty seven patients [55.4% male, mean age = 52.3 +/- 13.6 years] were evaluated. Sleep study confirmed OSA diagnosis in 91.7% of the studied patients. The reliability analysis of the BQ categories showed alpha Cronbach's as 0.70 and 0.50 for category 1 and category 2, respectively. BQ categories 1-3 were positive respectively in 88.5%, 67.5%, and 66.9% of the patients. The BQ and sleep study were in agreement for 82.1% of the cases. The sensitivity, specificity, positive and negative predictive values, and positive, and negative likelihood ratio of the BQ were calculated as 84.0%, 61.5%, 96.0%, 25.8%, 2.18%, and 0.26% respectively. BQ is useful as a screening test for diagnosing OSA in Iranian patients with sleep complaints; however, the test cannot be used for rolling out the OSA. Further studies on editing, modifying, and applying the BQ in a larger sample of patients are warranted in our society