Sleep disturbances caused by the symptoms of chronic obstructive pulmonary disease (COPD) are associated with airway constriction heterogeneity, which could be reflective of peripheral airway dysfunction, according to a study published in the Journal of Chronic Obstructive Pulmonary Disease.
To explore whether COPD sleep disturbances can be linked to heterogeneity of airway construction, the investigators used impulse oscillometry technique (IOS) to assess heterogeneity, the COPD and Asthma Sleep Impact Scale questionnaire (CASIS) to assess sleep quality, spirometry to assess forced expiratory volume in the first second (FEV1), and body plethysmography to assess air trapping and lung hyperinflation. Patients with a concomitant or previous diagnosis of obstructive sleep apnea or asthma were excluded from the study, leaving 50 enrolled participants with COPD (40 men, 10 women, 71±8 years old; BMI, 26.2±4.7kg/m2; FEV1 65%±25% predicted; mean±SD).
The mean CASIS score for participants was 36±3.3, with an R5-R20 value of 0.2±0.15 kPas L-1. For participants with increased R5-R20 values (>0.07 kPas L-1), CASIS scores were significantly higher (39±24; P =.02) when compared with normal R5-R20 values (21±17). When participants were categorized based on lung function for severely obstructed vs non-severely obstructed, or air trappers vs non-air trappers (FEV1< or >50% predicted; Residual Volume, RV> or <120% predicted, respectively), CASIS scores did not change (37±23 vs 33±25, respectively, P =.61 for FEV1; and 30±20 vs 40±23, P =.16 for RV).
The investigators concluded that the varying levels of severity and treatment approaches in participants could be a confounding factor, which indicates the need for larger cohort studies. Nevertheless, the results do show that patients with increased R5-R20 via IOS will likely present with more sleep disturbances, and “increased heterogeneity in airway constriction occurring during nighttime gives a reasonable pathophysiological insight for sleep disturbances referred by COPD patients.”
Marco B, Pierpaolo B, Emilia M, et al. Sleep disturbances in COPD are associated with heterogeneity of airway obstruction [published online September 6, 2018]. COPD. doi: 10.1080/15412555.2018.1504015