We will prospectively recruit 7000 OSA patients referred to the sleep center or China Medical University Hospital between 2020 and 2027. Polysomnographic (PSG) study data, clinical features, and health data from the National Health Insurance Research Database will be linked. Endotypic traits will be determined by PSG study parameters. The associations between clinical features, endotypic traits, and health outcome will be examined. Some patients will be invited to receive lung function tests, blood serum tests, blood gas tests, and cognitive function tests.