Long-term night-to-night variability of sleep-disordered breathing using a radar-based home sleep apnea test: a prospective cohort study.

STUDY OBJECTIVES: Night-to-night variability of sleep-disordered breathing (SDB) limits the diagnostic accuracy of a single measurement. Multiple recordings using a reliable, affordable method could reduce the uncertainty and avoid misdiagnosis, which could be possible with radar-based home sleep apnea testing (HSAT).

METHODS: We recruited consecutive patients with suspected SDB and performed contactless radar-based HSAT with automated scoring (Sleepiz One) over ten nights. During the first night, patients were simultaneously measured with peripheral-arterial tonometry.

RESULTS: Twenty-four of the 28 included patients could achieve a minimum of four measurements. The failure rate was 16% (201 of 238 measurements). The apnea-hypopnea index (AHI) and oxygen desaturation index were consistently lower with radar-based HSAT compared to peripheral arterial tonometry. The variability of the AHI was considerable, with a standard error of measurement of 5.2/h (95%CI 4.6-5.7/h) and a minimal detectable difference of 14.4/h (95%CI 12.7-15.9/h). Alcohol consumption partially accounted for the variability, with an AHI increase of 1.7/h (95%CI 0.6-2.8/h) for each standard drink. Based on a single measurement, 17% of patients were misdiagnosed, and 32% were misclassified for SDB severity. After five measurements, the mean AHI of the measured nights stabilized with no evidence of substantial changes with additional measurements.

CONCLUSIONS: Night-to-night variability is considerable and stable over ten nights. HSAT using radar-based methods over multiple nights is feasible and well tolerated by patients. It could offer lower costs and allow for multiple-night testing to increase accuracy. However, validation and reducing the failure rate are necessary for implementation in the clinical routine.

CLINICAL TRIAL REGISTRATION: "Recording of Multiple Nights Using a New Contactless Device (Sleepiz One Connect) in Obstructive Sleep Apnea", ClinicalTrials.gov, NCT05134402.