Diagnostic performance of a Doppler radar-based sleep apnoea testing device

<bold>Introduction:</bold> Inpatient polysomnography (PSG) is the gold standard for the diagnosis of obstructive sleep apnoea (OSA) but availability is limited due to both its complexity and costs. Home sleep apnoea testing devices are a diagnostic alternative in patients with increased risk for OSA. We evaluated the diagnostic performance of a Doppler radar technology based, contactless sleep apnoea testing device (CSATD) in a cohort of patients with a clinically increased risk of OSA. Method: Monocentric prospective study. Sleep monitoring with the CSATD SleepizOne+ (Sleepiz AG, Switzerland) was performed simultaneously with elective inpatient PSG. PSG was analysed blinded to the CSATD results according to AASM 2012 criteria by certified sleep physicians. The CSATD data were analysed automatically and independently by a dedicated software. <bold>Results:</bold> In total 102 patients, 66% male, with an average age of 55±15 years and BMI of 30±6 kg/m2 were included. The sensitivity and specificity of the CSATD for a PSG apnoea-hypopnoea-index (AHI) of ≥5/h were 0.89 (95%CI: 0.83-0.96) and 0.88 (95%CI: 0.73-1.0). The negative and positive predictive values were 0.62 (95%CI: 0.42-0.82) and 0.97 (95%CI: 0.94-1.0). The diagnostic agreement for the diagnosis of sleep apnoea (PSG AHI ≥5/h) was 89.8% and 100% for the CSATD AHI threshold of AHI≥5/h (n=79/88) or ≥15/h (n= 61/61). However, the concordance was poor in the classification of OSA severity, with 50% (13/26) concordance for mild, 38% (10/26) for moderate, and 76% (25/33) for severe OSA respectively. <bold>Conclusion:</bold> CSATD accurately identifies patients with OSA, particularly using an AHI threshold of ≥15/h. However, it performs subpar in disease severity stratification.