(A1213) Insomnia Severity Index and Arousal Threshold as Predictors of CPAP Adherence

Introduction: Continuous positive airway pressure (CPAP) is standard treatment for obstructive sleep apnea (OSA), but its effectiveness is limited by high non-adherence rates. Some studies suggest that low arousal threshold (ArTH), how easily a person awakens from sleep, and comorbid insomnia can negatively impact CPAP compliance. However, findings are not entirely consistent. This study aims to clarify the associations between CPAP adherence and insomnia and arousal threshold.

Methods: CPAP patients with insomnia severity index (ISI) scores (n = 32) were included. ISI and sleep study metrics were collected from electronic medical records and CPAP usage data from ResMed and Philips. Adherence was defined as usage ≥4 hours/night for ≥70% of nights. Statistical analyses included Wilcoxon-rank-sum and Fisher’s exact tests performed in R studio.

Results: ISI was significantly associated with CPAP adherence (p = 0.016) with patients with higher ISI scores (more severe insomnia symptoms) being less likely to be adherent to CPAP therapy. Among CPAP-adherent patients (n = 26), the average ISI was 14.64 and 6.75 among patients who were not CPAP-adherent (n = 6). There were no significant associations between ArTH level and adherence and between ISI and ArTH.

Conclusions: Insomnia severity significantly impacts CPAP adherence, with higher ISI scores linked to lower compliance. While no significant association was found between arousal threshold and adherence or between ISI and ArTH, further research with larger cohorts is needed to explore these relationships more comprehensively. Integrating tailored behavioral interventions for insomnia may enhance CPAP effectiveness and overall treatment outcomes in OSA patients.