Prevalence of Sleep Impairment and Assessment of Sleep Patterns using Pittsburgh Sleep Quality Index in Patients with Chronic Obstructive Pulmonary Disease

Background: Impaired sleep is reportedly common in chronic obstructive pulmonary disease (COPD) and its impact on Health-related quality of life has been documented. However, there is scarcity of data on sleep patterns and quality among patients with COPD in Nigeria. Methodology: Sixty clinically stable patients with COPD were evaluated. Information on demographics and presence of nocturnal symptoms were obtained. The Modified Medical Research Council (MMRC) dyspnea scale was used to assess severity of dyspnea. Subjective sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) and Daytime sleepiness was assessed using the Epworth sleepiness scale (ESS). Additionally, lung function was assessed by spirometry. In all the statistical tests, a p value of <0.05 was considered significant. Results: The mean age of the study population was 70 +/- 8years. Forty-nine patients (81.7%) had poor quality of sleep (PSQI > 5), with sleep duration and habitual sleep efficiency sub scores contributing the most to the total PSQI score. Three patients (5%) had excessive daytime sleepiness (ESS>9). Fortyfour (73.3%) patients reported disease related symptoms at night; cough (36.7%) was the most common nigh-time symptom. Severity of dyspnea and COPD according to Global Initiative for Obstructive Lung Disease (GOLD) stage were significantly associated with sleep quality (p=0.01 and 0.003 respectively). Conclusion: Results from this study suggest that overall sleep quality is poor in patients with COPD with many experiencing night-time symptoms. However, excessive daytime sleepiness was not common among the study population.