A longitudinal assessment of sleep variables during exacerbations of chronic obstructive pulmonary disease

Abstract

Although sleep disturbance is common in chronic obstructive pulmonary disease (COPD), relatively little is known on the effect of the exacerbation on sleep quality. Accordingly, we longitudinally assessed sleep variables during exacerbations and clinical stability. This is a sub-study of a larger observational analysis. Inclusion criteria were clinically stable COPD and two or more clinical exacerbations in the preceding 12 months. Patients were followed for approximately 6 months and during this time the following were recorded daily: (1) COPD exacerbations, which were determined in two ways, clinically and symptom defined using the exacerbations of chronic pulmonary disease tool (EXACT); (2) daytime sleepiness, which was measured using the Stanford Sleepiness Scale; (3) subjective awakenings, which was measured from a sleep diary; and (4) sleep duration, efficiency, and objective awakenings, which was measured from actigraphy. These variables for exacerbation and non-exacerbation days were compared. Seventeen patients (9 male, age 63 ± 12 years, forced expiratory volume in 1 second 52 ± 20%) entered data over 135 ± 18 days. During this time, 15 patients had 27 symptom-defined exacerbations and 8 had 9 clinically reported exacerbations. Symptom-defined exacerbation days were 26% of the total study days. More daytime sleepiness, decreased total sleep time (TST), and decreased sleep efficiency (SE) were present during exacerbations compared with clinical stability (p < 0.001). These disturbances tended to be greater during clinically reported exacerbations than during unreported events (p < 0.05). Increased daytime sleepiness, less TST, and poorer SE are present during COPD exacerbations.