CPAP compliance - A two year follow-up study: The Icelandic sleep apnea cohort (ISAC)

Objectives: To estimate the main determinants of continuous positive airway pressure (CPAP) usage in a well defined population. Methods: Patients diagnosed with moderate to severe obstructive sleep apnea (OSA) in Iceland were invited to participate. Altogether 822 OSA patients participated (665 males, 157 females). Two years later they were invited for a follow-up evaluation. Results: Altogether 741 (90%) OSA patients returned for the 2 year follow-up. Of those, n=475 (64%) were using CPAP and n=266 were non-users. Of the nonusers, 17% had returned the device within 30 days, and altogether 30% had returned the device within 3 months. The average±SD use per night was 6.2±1.9 hours and only n=47 used CPAP 2 , p 35 kg/ 2 and ESS >10, altogether 76% were using CPAP at the follow-up visit compared to 44% of those with BMI Conclusion: Two-thirds of moderate to severe OSA patients are regular CPAP users after 2 years and the majority of them have high usage per night. Obesity, OSA severity, hypertension status and sleepiness are all important determinant of long-term compliance.