ACCESS-OSA: a randomized controlled trial for accurate, accessible, and cost-effective screening solutions for obstructive sleep apnoea: study protocol.

Obstructive sleep apnoea (OSA) is common and burdensome, yet current diagnostic pathways remain costly and often misclassify patients. Single-night polysomnography (PSG), the diagnostic gold standard, fails to capture night-to-night variability in severity, is difficult to access and costly. Emerging technologies enable multi-night in-home evaluation, but robust comparative evidence regarding accuracy and cost-effectiveness is lacking. This study will evaluate (a) the diagnostic accuracy of three multi-night in-home devices versus conventional single night PSG; (b) the patient and signal characteristics that optimize diagnostic performance; and (c) the cost-effectiveness of these pathways for clinical implementation. We will conduct a three-arm randomized diagnostic strategy trial (n = 500) enrolling adults referred for suspected OSA over a recruitment period of several years from July 2025. All participants will undergo both conventional single-night PSG and multi-night assessment with an under-mattress sensor, oximetry ring, and forehead EEG device. Participants will be randomized to one of three diagnostic pathways, determining the order in which sleep physicians interpret test results. Sleep physicians will provide sequential diagnostic decisions at each stage, and a blinded expert panel will determine consensus diagnoses. The primary outcome is diagnostic accuracy of each pathway compared with consensus diagnosis. Secondary outcomes include cost-effectiveness, patient-reported acceptability, clinical confidence, self-reported long-term symptoms, and health and quality of life outcomes over 12 months follow-up. Findings will provide definitive evidence for whether simplified and accessible multi-night testing can improve accuracy and cost-effectiveness of OSA diagnosis in routine care.