People with obstructive sleep apnea (OSA) who are early risers or up with the “lark” (a bird which sings before dawn) use their continuous positive airway pressure (CPAP) for a longer duration each night, according to a study published in the Annals of the American Thoracic Society.^1,2

The multicenter Apnea Positive Pressure Long-term Efficacy Study (APPLES) trial published in 2012 had demonstrated the beneficial effects of CPAP (vs sham CPAP) in improving sleepiness, especially in persons who had severe OSA (AHI > 30). To investigate if the chronotype of OSA affected the daily adherence to CPAP (hours per night) treatment in the same group of patients, researchers from Yale University School of Public Health, Yale University School of Medicine and Stanford University School of Medicine carried out a secondary analysis of the APPLES study in 469 patients, most (68%) of them were male. Majority had severe OSA (AHI 39.8 per hour) and obesity (average BMI 32).

The chronotype was determined with the help of the Morningness-Eveningness Questionnaire (MEQ). The MEQ score of ≥ 59 was categorized as morning type, ≤ 41 as evening type and 42-58 as intermediate chronotype. Based on the MEQ score, 44% of patients were found to have a morning chronotype, 8% had an evening chronotype, while 47% had an intermediate chronotype.

Analysis of data revealed that the average duration of nighttime sleep was 7 hours. The morning chronotype patients reported shorter sleep per night on weekends (7.3 hours) vs the intermediate (7.6 hours) vs the evening chronotype patients (7.9 hours). Evening chronotype patients were younger; the intermediate chronotype reported highest anxiety. No differences were observed for sleep apnea, insomnia or sleepiness among the three groups.

Over the 6 months of the study, the use of CPAP was higher by 40 minutes per night among participants with morning chronotype compared to those with intermediate chronotype. After adjusting for confounding variables, this duration came down to 32.8 minutes per night. Feeling unrested or tired during the day was reported maximally by the evening chronotype patients (41%) compared to the intermediate (28.3%) and the morning chronotype patients (17.4%). With every hour of use of CPAP, sleepiness and functional status was seen to improve. Factors such as duration of sleep or weekend catch-up sleep did not influence CPAP adherence.

Compared to the evening and intermediate chronotypes, OSA patients with morning chronotype were more likely to adhere to CPAP treatment with better clinical outcomes. These findings suggest chronotype as a predictive factor for adherence to CPAP treatment among patients with OSA.

References

1. Knauert MP, et al. Morning chronotype is associated with improved adherence to continuous positive airway pressure among individuals with obstructive sleep apnea. Ann Am Thorac Soc. 2023 Mar 14. doi: 10.1513/AnnalsATS.202210-885OC.
2. Short E. Early Birds with sleep apnea may get more CPAP benefits. Available at: https://www.medpagetoday.com/pulmonology/sleepdisorders/103827. April 1, 2023. Accessed on April 8, 2023.