Seasonal Differences in the Factors Affecting Sleep Restfulness in Patients with Obstructive Sleep Apnea Receiving Continuous Positive Airway Pressure Therapy.

Background Restful sleep exhibits seasonal variation and is an important sleep quality indicator that affects various morbidities and mortality rates. We investigated whether the factors influencing restful sleep differed according to season in patients with obstructive sleep apnea (OSA) receiving continuous positive airway pressure (CPAP) therapy. Methods We conducted a prospective single-center study. From June 2024 to September 2024, 137 patients with OSA receiving CPAP therapy were given a thermohygrometer and instructed to install it in their bedroom for 1 year. We administered a sleep-related questionnaire, including subjective sleep duration, sleep restfulness, and questions from the Japanese version of the Epworth Sleepiness Scale (JESS), each season. Sleep restfulness was rated on a 5-point Likert scale, with 5 indicating restful sleep. Results The final study cohort comprised 126 patients (102 men and 24 women). Restful sleep was independently correlated with subjective sleep duration in the spring. Restful sleep was significantly associated with the JESS score, daily duration of CPAP use, and good adherence to CPAP therapy in summer; the presence of a bed partner, subjective sleep duration, JESS score, allergy medication use, daily duration of CPAP use, good adherence, bedroom relative humidity, and dehumidifier use in autumn; and body mass index, JESS score, daily duration of CPAP use, good adherence, and humidifier use as a CPAP device accessory in winter. Conclusion The factors influencing restful sleep vary by season in patients with OSA receiving CPAP therapy. Therefore, to achieve restful sleep, attention must be focused on the different factors associated with each season.