O073 Traditional Clinical and Novel Oximetry Measures as Predictors of Cardiovascular Events

INTRODUCTION: Intermittent hypoxia is a key mechanism linking Obstructive Sleep Apnoea (OSA) to cardiovascular disease (CVD). Oximetry analysis could enhance understanding of which OSA phenotypes are associated with CVD risk. We investigated if traditional clinical and novel oximetry measures including hypoxic burden (HB) calculated from the polysomnogram SpO2 signal can predict CVD outcomes in all-comers and OSA subsample cohorts from the Sleep Heart Health Study (SHHS). METHODS: CVD mortality outcome and complete covariate information was used. We implemented 31 oximetry measures and assessed the performance of the parameters in predicting CVD outcomes (CVD death or incident CVD) in the all-comers and sleep apnoea subsamples. The performance of each measure was assessed using an adjusted Cox proportional hazard ratio (HR) analysis. RESULTS: In the general subsample, HB successfully predicted CVD death (HR>1.8, p<0.05) but did not predict incident CVD. In the sleep apnoea subsample (AHI>5) with no CVD at baseline, none of the SpO2 measures we considered predicted incident CVD. DISCUSSION: The ability of HB to predict CVD outcomes depends on the cohort and the CVD outcome. Our analysis of the selected SpO2 measures in an OSA subsample did not find strong links between any oximetry measures and incident CVD, and therefore no strong candidates for CVD risk phenotyping in the sleep clinic. Further work is needed to understand the complex relationship between OSA-related intermittent hypoxia patterns and development of CVD to further understanding of OSA phenotypes at risk of CVD consequences.