Impact of Comparing Treatment Status With Other CPAP Users

Inclusion Criteria

• •Eligibility criteria:
• •The patient has been diagnosed with SAS and has initiated CPAP therapy according to the criteria of Japanese public health insurance system(i.e., Apnea hypopnea index (AHI) \>= 20/h by polysomnography, or respiratory event index (REI) is \>= 40/h by portable monitoring device at the time of OSA diagnosis).
• •The patient makes regular outpatient visits for the continuation of CPAP therapy according to the requirements for the coverage of Japanese public health insurance.
• •At least three months have passed since the introduction of a CPAP remote monitoring system, and the researchers can confirm CPAP adherence online.
• •The patient has mailing address necessary for sending feedback by post or email.
• •3. After the number of patients who have provided consent reaches the planned sample size, a postal item will be sent to confirm the accuracy of the participant's address. The mailing will include a postcard for reply or QR code that allows the research team to verify that the participant has received the item. Participants whose receipt of the mailing can be confirmed will be eligible for randomization.
• •4. Participants will be randomly assigned to either the control group (receiving only information about their own CPAP adherence) or the peer comparison group (receiving information about their own adherence plus the summary of adherence data from all participants).
• •5. Thereafter, for six months, participants will receive by mail monthly information about their CPAP adherence. Each mailing will include a postcard for reply and a QR code that allow participants to notify the researchers that they have opened the mailing.
• •In the control group, the following information will be provided:(1) Average daily CPAP usage time in the previous month, and (2) Percentage of days with CPAP usage more than or equal to 4 hours per day.In the peer comparison group, in addition to the above, the following information will be provided: (3) Mean daily CPAP usage time among all participants, (4) Percentage of days with CPAP usage ≥ 4 hours per day among all participants, and (5) Participant's rank among all participants based on average daily CPAP usage time.