Prevalence of OSAS in Chinese Elderly and Its CPAP Compliance

Objective: Obstructive sleep apnoea syndrome (OSAS) is a common form of sleep-disordered breathing (SDB) causing sleep fragmentation, daytime sleepiness, cognitive function impairment, and poor health status in addition to increased risk of cardiovascular complications. OSAS is equally common among the middle-aged male Caucasian and Hong Kong (HK) Chinese populations with a prevalence of at least 4%. However, the prevalence of OSAS in the elderly population in Asia including HK is unknown. Study Design: A sleep questionnaire will be conducted for 1000 subjects aged at least 60 yrs in the elderly community centers focusing on symptoms of OSAS, subjective sleepiness, restless leg syndrome, and sleep-related habits and routines, in addition to past medical history and medications. Home sleep study (EMBLETTA) capable of recording sleep (a single EEG channel), respiratory events, snoring, respiratory efforts and oximetry will be performed on 300 subjects randomly. Those who have negative or technical inadequate EMBLETTA study with a high pre-test probability of moderate to severe OSA will be invited to undergo hospital-based polysomnography for confirmation of their sleep apnoea status. Subjects with AHI>15/hr regardless of symptoms or those with AHI 5-15/hr plus comorbid conditions or excessive daytime sleepiness will be offered continuous positive airway pressure (CPAP) titration followed by CPAP treatment, with serial assessment of subjective sleepiness, quality of life, and cognitive function. Outcome measures: the prevalence rates of SDB (AHI>10, >15 and >30/hr), OSAS, and other sleep disturbances, such as restless leg syndrome (RLS). In addition, we will examine the factors which are predictive of the presence of SDB in this population, and assess the CPAP acceptance, compliance, and treatment outcome of those with OSAS.