O079 The effect of long-term CPAP on subclinical markers of coronary artery disease in clinic patients with OSA

Abstract Background In view of the current uncertainty about the relationship between obstructive sleep apnoea (OSA) and development of major adverse cardiovascular events (MACE) we studied the long-term effect of continuous positive airway pressure (CPAP) on important subclinical markers known to be on the causal pathway to coronary artery disease (CAD) Methods We used our database of sleep clinic patients (n=4,226) who had baseline phenotypic assessments, between 2006 and 2010, including level 1 polysomnography to determine the presence and severity of OSA. We performed follow-up assessments between 2019-22 on 2 groups of consenting participants who were alive and free of MACE at baseline and during the follow-up period: those with long-term good CPAP use and those with poor or no use. We will compare follow-up High sensitivity Troponin-I and coronary calcium scores between groups, using propensity score matching methods. Progress to date A total of 263 patients completed follow-up assessments and will undergo propensity score matching. Of these, 134 had good CPAP use and 129 had no or poor CPAP use. The two groups had similar baseline characteristics: median age 62 vs 60 years, male 67% vs 64%, body-mass-index 32.6 vs 30.0kg/m2 respectively. Intended outcome and impact This project is intended to provide further insight into the relationship between OSA and risk for developing CAD, by studying the effect of long-term good CPAP use, compared to no or poor CPAP use, on changes in established sub-clinical biomarkers of coronary disease.