Screening for Obstructive Sleep Apnea in High-risk Patients in a Danish Rural Population: A Pilot Feasibility Study

Participant-reported experience with the NightOwl device, assessed at Day 3 with a study-specific questionnaire. Items are rated on a 0-100 visual analog scale (0 = completely disagree, 100 = completely agree) and span four dimensions: 1) device usability (overall ease of use, learnability, adequacy of information, adherence to instructions, interference with daily life, sleep disturbance), 2) sensor application and overnight fit, 3) smartphone-application comprehensibility and ease of use, and 4) confidence in measurement and perceived health empowerment. Reported as mean (SD) per dimension, and as an overall mean score.

Assessed identically to Outcome 1 for the SleepImage Device.

For each device (NightOwl, SleepImage, Nox T3), the number of nights yielding an analyzable recording meeting predefined technical criteria, divided by the number of nights the device was worn, expressed as a percentage. The complementary proportion of failed, incomplete, or non-analyzable recordings is reported per device.

Number of enrolled participants divided by the duration of the recruitment period, expressed as participants per month. The recruitment period is defined as the time from enrollment of the first participant to enrollment of the last participant.

Proportion of participants enrolled via each recruitment route (diabetes outpatient clinic, general practice, patient-organisation/social media), reported as frequencies.

Number of participants obtaining three nights of home monitoring with analyzable recordings from all devices scheduled for each night (NightOwl and SleepImage on nights 1-2; NightOwl, SleepImage and Nox T3 on night 3), divided by the number enrolled, expressed as a percentage.

Total number of home monitoring nights attempted per participant to obtain three nights with analyzable recordings from all devices scheduled for that night. A night is repeated with all scheduled devices if the recording from one or more of these devices fails, is incomplete, or is non-analyzable, as assessed against predefined technical criteria; nights are repeated until three analyzable nights are obtained or the participant declines further attempts. Reported as mean (SD) and median (range) per participant, and as proportion of participants needing any additional test nights.

Among participants who declined further attempts before three analyzable nights were obtained, the number of nights attempted and the number of analyzable nights obtained (0, 1, or 2) at discontinuation. Reported as median (range) attempts, together with the number and proportion of enrolled participants discontinuing before obtaining three analyzable nights.

Completeness of planned baseline assessments, reported as the proportion of participants with fully complete baseline data across all assessments and as the proportion completed per individual assessment (Berlin Questionnaire, STOP-Bang, Epworth Sleepiness Scale, ENT examination with flexible endoscopy, autonomic neuropathy assessment, blood pressure, lipids, HbA1c).

The fraction of participants with mild, moderate and severe obstructive sleep apnea according the cardio-respiratory monitoring the final test night relative to all participants. Scoring is according to the 2012 scoring rules by the American Association of Sleep Medicine. This will guide power calculation for the future main study.