Discrimination of night-time cough in patients with stable COPD

Introduction:
Lack of awareness of night-time respiratory symptoms can lead to worsened COPD control, disturbed sleep and impaired daytime performance. The present study focuses on description of frequency, severity and characteristics of night-time cough in patients with stable COPD stages II-IV.

Methods:
Night-time cough was monitored by LEOSound lung sound monitor in patients with stable COPD stages II-IV. In 30 patients with ten patients in each stage group night-time cough was analysed for frequency, severity and characteristics.

Results:
Cough was found in all patients ranging from 1 to 294 events over the recording period. Cough mostly occurs in epochs (75\%). In 29 patients cough epochs were monitored, ranging from 1 to 75 events. The distribution of cough epochs showed the highest amount in COPD GOLD stage III. Active smokers had significantly more productive cough epochs (61\%) than non-smokers (24\%) (p = 0.0033).

Conclusions:
We found a high rate of night-time cough in patients with COPD, especially in those with COPD GOLD stage III. Productive cough was primarily related to still existing smoking status. LEOSound lung sound monitor offers a practical and vulnerable opportunity to evaluate night-time cough objectively.