Frequent sputum production is associated with disturbed night's rest and impaired sleep quality in patients with COPD

In this study, we measured night's rest parameters measured with an accelerometer and sleep quality in mild to very severe patients with COPD. Furthermore, our aim was to investigate the association between night's rest parameters and clinical variables and the association between sleep quality and quality of life or health status.

Mild to very severe COPD patients were recruited from general practitioners and outpatient clinics of general hospitals to participate in a cross-sectional study on physical activity in patients with COPD. A total of 103 patients (mean age 65 years, 67 % male) wore the accelerometer during night's rest for at least four nights and were included in the analyses.

No significant associations were found between objectively measured body movements during night's rest or subjective sleep quality and lung function, dyspnoea severity, body composition and physical activity during the day. Patients with frequent sputum production during the day had a higher number of sitting transitions during the night (5.3 vs 4.3 sitting transitions) and more frequently got out of bed compared to patients who hardly ever produced sputum during the day (1.0 vs 0.8 times per night). Furthermore, these patients also reported worse sleep quality (Pittsburgh sleep quality index (PSQI) score 4 vs 3).

Our results indicate that objectively measured body movements during night's rest like body postures and transitions are not related to sleep quality in patients with COPD. We did find an association between frequent sputum production and disturbances during night's rest and sleep quality. Future studies should investigate whether the treatment of mucus hypersecretion leads to improved night's rest.