0801 Predictive value of heart rate variability on BP outcomes in OSA status – a 10yr longitudinal study

Abstract

Abstract Introduction The apnoea/hypopnoea index (AHI) is commonly used as the indicator of OSA severity, but it cannot fully describe the illness severity, comorbidities, or treatment response. Heart rate variability (HRV) is a non-invasive way of detecting cardiac autonomic nervous system activity variations. It adds a new dimension to help understand the interplay between cardiac and nervous systems involvement in OSA. Aims: To explore the associations of HRV with OSA status in subjects from a longitudinal study where measurements were performed at 4-yr and 10-yr follow-up visits. Methods The cohort was established in 2003 to examine the prevalence of OSA in primary school children. During the 4-yr follow-up, HRV data in the time domain and frequency domain for 243 subjects when they were 10-17 years old were collected. Participants were invited to return for the 10-yr follow-up visit to undergo anthropometric measurements, overnight sleep study, and 24-hour ambulatory blood pressure (ABP) monitoring. Results Two hundred forty-three participants returned for the 10-yr follow-up. Participants who completed the HRV measurements at the 4-yr follow-up were included in this preliminary analysis. There were 122 participants (48.4% with OSA). Participants with OSA (AHI >=5 event/h) at the 10-yr follow-up had a higher high frequency (HF) norm, a kind of HRV parameter, at the 4-yr follow-up than those without OSA (40.5 ±22.1n.u.) vs (33.7 ±15.2n.u.) (P = 0.030). Conclusion HRV parameters combined with OAHI at 4yr likely partially explain SBP, and it can better predict SBP at 10yr than independent OAHI. HRV is prone to have an interaction effect, instead of a mediation effect, to help us predict SBP. Support (if any)