Abstract MP45: Nocturnal Hypoxemia, Obstructive Sleep Apnea and the Risk of Cardiovascular Diseases and Mortality: Insights From the Atherosclerosis Risk in Communities Participants of the Sleep Heart Health Study

Background: Nocturnal hypoxemia may better capture disease burden than obstructive sleep apnea (OSA). Using a subset of participants from the Atherosclerosis Risk in Communities (ARIC) study who participated in the Sleep Heart Health Study (SHHS), we examined the association of nocturnal hypoxemia and OSA with cardiovascular diseases (CVD) and mortality in a white, older cohort in the US. Methods: A total of 1,455 participants free of CVD had an in-home, overnight polysomnogram; nocturnal hypoxemia (% of total sleep time with oxygen saturation <90%) and OSA (apnea-hypopnea index - # of apneas/hypopneas per hour of sleep) were derived from these readings. Incident CVD events and mortality were identified through the end of 2019 using annual telephone calls, hospital discharge lists and death certificates and were adjudicated by physician review. Included in this analysis were coronary heart disease (CHD), heart failure (HF), stroke, any CVD event (CHD, HF, or stroke), atrial fibrillation (AF), and all-cause mortality. We used Cox proportional hazards models to assess the association of nocturnal hypoxemia (categories: <1%, 1-<5%, ≥5%) and OSA (categories: <5, 5-<15, 15-<30, ≥30) with each outcome. Results: At the sleep assessment, participants had a mean (SD) age of 62 (6) years, 53% were female, and 14% had a nocturnal hypoxemia ≥5%. Over a mean follow-up of 17.8 years, a total of 408 participants had any CVD event, and 602 died. Nocturnal hypoxemia ≥5% was associated with incident HF and all-cause mortality in the fully adjusted model (Table). Nocturnal hypoxemia ≥5% was also associated with incident CVD and AF in Model 1; however, adjustment for body mass index attenuated these associations (Table, Model 2). OSA was not associated with the outcomes in any model (data not shown). Conclusion: Further research is needed to understand the distinction between nocturnal hypoxemia and OSA and how they relate to the risk of CVD and mortality. It is possible that reducing nocturnal hypoxemia should be targeted over OSA for CVD prevention.