Sleep, the Forgotten, Yet Potentially Modifiable, Dimension in Chronic Obstructive Pulmonary Disease Care

To the Editor:

We read with interest the latest Global Initiative for Chronic Obstructive Lung Disease Executive Summary by Agustí and colleagues published in the Journal (1). We applaud the authors and the Global Initiative for Chronic Obstructive Lung Disease committee members for publishing this thorough and updated guide to chronic obstructive pulmonary disease (COPD) and COPD treatment recommendations. The authors present a new definition of COPD, which varies from previous documents and focuses exclusively on characteristics that distinguish this disease from other diseases (1). The authors define COPD as a heterogenous lung condition characterized by chronic respiratory symptoms (dyspnea, cough, and/or expectorations) due to abnormalities of the airways (bronchitis, bronchiolitis) and/or alveoli (emphysema) that cause persistent, often progressive, airflow obstruction (1). It should be noted that COPD results from cumulative and repeated genome and environment interactions throughout the course of a lifetime (1). We support the authors in identifying multiple comorbidities with direct relationships to COPD, some of which are potentially modifiable. Consistent with a paucity of clear evidence from long-term randomized trials, the approach to sleep issues in COPD, including obstructive sleep apnea (OSA) (other sleep disorders, sleep deprivation, sleep fragmentation, and sleep-related hypoxemia [2, 3]), was minimally discussed. This lack of discussion is understandable in the context of our evidence base given the lack of rigorous trials testing the impact of screening for sleep disorders (e.g., OSA, insomnia) in the COPD population. However, it is known that sleep issues are present in 40–75% of patients with COPD (4, 5), and commonly used COPD questionnaires (COPD Assessment Test, St. Georges Respiratory Questionnaire) include questions about sleep symptoms. Therefore, we urgently need evidence to help us understand the optimal approach to identifying sleep comorbidities in COPD among symptomatic patients. By approaching these concerns with rigorous science, we anticipate that future COPD-specific guidelines will have much more to say about the role and implications of identifying sleep disorders. In the meantime, the NIH COPD Action Plan recommends assessing for and treating known comorbid conditions in patients with COPD. To effectively manage patients with known sleep comorbidities, clinicians should pursue evidence-based treatments that are known to improve quality of life, e.g., continuous positive airway pressure for OSA and cognitive behavioral therapy for insomnia.