Dados do Trabalho

Título

Sleep-onset time variability and sleep characteristics on weekday and weekend nights in patients with COPD.

Introdução

Although it is primarily a respiratory disease, chronic obstructive pulmonary disease (COPD) has many extra pulmonary features, including sleep disturbances. Sleep irregularity, one of the main sleep disturbances, can be measured by sleep-onset time variability (i.e., intrasubject standard deviation of sleep-onset time). Despite having been investigated in many diseases, variability of sleep-onset time was not yet thoroughly investigated in individuals with COPD.

Objetivo

To analyze the repercussion of sleep-onset time variability on the quantity and quality of sleep in individuals with moderate-to-severe COPD and to describe sleep characteristics on weekday and weekend nights in this population.

Métodos

Pulmonary function was assessed using a portable spirometer and exercise capacity was assessed by the 6-minute walk test. Sleep was objectively assessed by a sleep monitor for seven consecutive nights. For analysis, individuals were divided into two groups according to results of sleep-onset time variability, characterized by intrasubject standard deviation of sleep-onset time (SOTV) ≥60 min or <60 min.

Resultados

The sample comprised 55 individuals (28 males; mean age 66±8 years; median FEV1 55 [38-62]%predicted). When compared with the SOTV<60min group (n=24), the SOTV≥60min group (n=31) presented shorter total sleep time (5.1±1.3h vs. 6.0±1.3h; P=0.006), lower sleep efficiency (73±12% versus 65±13%; P=0.030), longer wake time after sleep onset (155±66 min versus 115±52 min; P=0.023), longer duration of wake bouts (19 [16-28] min versus 16 [13-22] min; P=0.025), and higher number of steps at night (143 [104-213] versus 80 [59-135]; P=0.002). In general, sleep characteristics were poor regardless of the day of the week, and the only significant difference being that the participants woke up about 30 min later on weekends than on weekdays (P=0.013).

Conclusões

Sleep-onset time varied over 1h in a standard week in the majority of individuals with COPD in this sample, and a more irregular sleep onset indicated poor sleep quality both on weekdays and weekends. Sleep hygiene orientation could benefit these individuals if integrated with their health care.

Palavras -chave

Pulmonary disease, chronic obstructive; Sleep; Actigraphy.