The association between sleep quality, health status and disability due to breathlessness in chronic obstructive pulmonary disease patients

Background Chronic obstructive pulmonary disease (COPD) increases susceptibility to sleep disturbances. This study aimed to evaluate the association between COPD severity criteria with sleep quality. Methods One hundred fifty-eight patients in Rasul Akram Hospital of Iran University of Medical Sciences, Tehran, Iran, from April 2019 to March 2021 diagnosed with COPD were examined using the Pittsburgh Sleep Quality Index (PSQI), COPD Assessment Test (CAT), modified Medical Research Council (mMRC) dyspnoea scale, spirometry and pulse oximetry. Results Of 158 subjects, 125 patients were male (79%), and 33 were female (21%). The mean subject's age and FEV1/FVC ratio were 62.6 +/- 11.5 and 65.6 +/- 14.9%, respectively. The mean CAT scoring and Spo2 saturation reported 16.2 +/- 7 and 91.5 +/- 10.8%, respectively. The mean PSQI score was 8.2 +/- 3.8. The association between PSQI score with FEV1 and FEV1/FVC ratio was not statistically significant (p = 0.64 and 0.58, respectively), whereas the association between PSQI scores with CAT score (p < 0.0001, r(2) = 0.51) and dyspnoea severity (p < 0.0001, r(2) = 0.29) were statistically significant. The patients with higher CAT score demonstrated poor sleep quality, particularly in longer sleep latency (p = 0.001, r(2) = 0.056), bad subjective sleep quality (p < 0.0001, r(2) = 0.286), lower sleep efficiency (p = 0.002, r(2) = 0.077), higher sleep disturbance (p < 0.0001, r(2) = 0.225), daytime dysfunction (p < 0.0001, r(2) = 0.259) and sleep medication intake times a week (p = 0.01, r(2) = 0.069). Dyspnoea severity was attributed to bad subjective sleep quality (p < 0.0001, r(2) = 0.069), higher sleep disturbances (p = 0.005, r(2) = 0.08), and daytime dysfunction (p < 0.0001, r(2) = 0.108). Conclusion The PSQI has a significant association with the CAT and mMRC for COPD patients and is linked to the disease's severity.