P032 Prospective Crossover Trial of Positional and Continuous Positive Airway Pressure Therapy (PaCT) for the Treatment of Mild-to-Moderate Positional Obstructive Sleep Apnoea

INTRODUCTION: Positional obstructive sleep apnoea (pOSA), defined by a supine-to-non-supine AHI ratio ≥2, is a phenotype present in a significant subset of patients with sleep-disordered breathing. CPAP has been the gold standard for OSA treatment since its first description in clinical use, although various practical and patient factors may preclude its use. Positional therapy (PT) provides an alternative for pOSA – shown to be effective in restricting supine sleep, thereby reducing the frequency of events and improving outcomes. METHODS: Prospective, single-centre crossover trial of consecutive, treatment-naïve participants with symptomatic, mild-to-moderate pOSA on diagnostic polysomnogram. Eligible participants were randomised to undergo paired treatment CPAP and PT polysomnography to assess efficacy. Participants thereafter received a two-month trial of each, according to randomisation. Adherence, symptom, quality of life (QoL) measures, and patient preference were assessed. RESULTS: 53 participants completed treatment and follow-up. Mean age was 55.1±12.7 years. 30 participants were male (56.6%). Median BMI was 30.1kg/m2 (27–34). Median baseline AHI was 14.4 (9.9–20.2). Median baseline Epworth Sleepiness Scale (ESS) was 12 (10–14) and improved after treatment with positional [8 (6–11); p=0.001] and CPAP [8 (6-11); p<0.001] therapies. There was no difference in ESS reduction between treatment groups (p=0.691). There was no significant difference in usage between therapies (p=0.877). QoL measures were also assessed. DISCUSSION: In this cohort with symptomatic mild-to-moderate pOSA, treatment with both PT and CPAP resulted in comparable, clinically significant symptomatic improvement with similar usage. Our findings suggest either therapy can be considered effective in appropriately selected patients.