Impact and mechanisms of night-to-night variability in sleep apnoea severity on health and treatment outcomes

Obstructive sleep apnea affects 1 billion people globally and is associated with major adverse physical and mental health outcomes and elevated accident and cardiovascular event risks.
However, there is considerable heterogeneity in pathophysiology and disease consequences. This makes identification of individual patients most at risk of adverse outcomes and appropriate treatment selection problematic in clinics. This is further complicated by inadequate diagnosis practices unable to identify causal mechanisms. Furthermore, obstructive sleep apnea diagnosis, severity categorisation and subsequent clinical management and treatment decisions rely entirely on single night sleep study to quantify the rate of breathing disturbances using the apnoea hypopnea index (AHI). The AHI, and indeed other sleep measures, vary markedly from night to night, particularly in people with mild to moderately severe obstructive sleep apnea. Emerging evidence suggests that 20- 50% of patients are
misdiagnosed based on a single night study. This will markedly impact on clinical management, costs and outcomes. This project will, for the first time, utilise novel nonintrusive sleep sensor technology to monitor sleep and health outcomes for an extended period in the home environment to determine 1) how much night to night variability in AHI (N2NV) impacts health outcomes, 2) identify the key physiological and behavioural factors that drive N2NV and 3) explore the impact of N2NV on effectiveness of OSA treatment in improving health outcomes.