O055 CPAP adherence in practice: do endotypes hold predictive value?

Abstract Introduction Obstructive Sleep Apnoea (OSA) is commonly treated with Continuous Positive Airway Pressure (CPAP), but adherence to therapy is often poor in real-world settings. Recent physiology lab studies have identified physiological OSA endotypes that may influence patient tolerance to CPAP treatment and, in turn, adherence outcomes. This pilot study investigates whether this physiological bias against CPAP is detectable in real-world populations by examining correlations between endotype metrics and long-term CPAP adherence in a clinical cohort. Methods Data from 40 adult OSA patients with diagnostic polysomnography and long-term CPAP adherence records was extracted from our institutional research database and retrospectively analysed. Two matched sub-cohorts with good and poor CPAP adherence were defined. Polysomnographic signals were processed using existing methods to estimate the values of four physiological OSA endotypes: chemoreflex loop gain, critical airway pressure (Pcrit), respiratory arousal threshold, and pharyngeal muscle responsiveness. Endotype distributions were statistically compared between the two groups. Results None of the four endotypes showed statistically significant differences between the adherent and non-adherent groups. Weak correlations were observed between adherence and both Pcrit and arousal threshold, aligning with existing physiological models of CPAP response. Discussion This study did not find significant associations between physiological endotypes and CPAP adherence in a clinical cohort. While weak trends consistent with previous mechanistic hypotheses were observed, these findings suggest that endotypes alone may have limited predictive value in real-world settings. Ongoing work is evaluating these associations in a large-scale cohort to account for potential confounding factors such as behavioural and socio-environmental influences.