Subjective sleep quality is associated with disease status in COPD patients. The cross-sectional Greek UNLOCK study

Purpose: The association of chronic obstructive pulmonary disease (COPD) severity and related health status with sleep quality remains unclear. We aimed to investigate the association between COPD and sleep quality in the Greek national branch of the UNLOCK cohort.

Methods: A sample of 257 COPD patients enrolled cross-sectionally from primary care in Greece. Sleep quality was assessed by the COPD and Asthma Sleep Impact Scale (CASIS-7 items) questionnaire (higher score indicates worse sleep quality). We tested for associations of sleep impairment with health status (CAT and mMRC scores), exacerbations, hospitalizations, GOLD 2018 ABCD status, inhaler adherence, frailty, and sense of coherence, adjusting for age, gender, smoking status, and comorbidities.

Results: The majority of patients reported uncontrolled symptoms (91% with ≥ 10 CAT or 61% with ≥ 2 mMRC). Mean (SD) age was 65 (12.3) with 79% males. CASIS-7 mean (SD) score was 37.7 (12.9). After adjustments, CASIS was significantly associated with worse health status (e.g., CASIS increased with CAT ≥ 10 [β = 12.53, (95% CI, 6.82, 18.25); p < 0.001], mMRC ≥ 2 [β = 4.96, (95% CI, 1.56, 8.34); p = 0.004]), COPD severity (CAT-based GOLD BD [β = 8.88 (95% CI, 2.50, 15.26); p = 0.007]), frailty [β = 8.85 (95% CI 4.45,13.25); p < 0.001], and sense of coherence [β = -0.14 (95% CI -0.21, -0.06), p < 001]. When using a CASIS cut-off score of 30 as indicator of sleep impairment, additional to the aforementioned associations, we found increased risk for sleep impairment with ≥ 2 exacerbations/year and poor inhaler adherence (p value < 0.05).

Conclusions: Our study suggests that worse health status and COPD severity are associated with poor sleep quality in COPD patients.