153 patients undergoing pulmonary rehabilitation were screened for obstructive sleep apnea via i) ApneaLink (ResMed, Munich) and ii) the Berlin Questionnaire. The Epworth Sleepiness Scale (ESS) was administered to grade daytime sleepiness. Results of ApneaLink screening and questionnaires were prospectively compared. The Respiratory Disturbance Index (RDI) was used to compute predictive performance of the Berlin Questionnaire for obstructive sleep apnea