Prevalence of sleep apnoea and its associated impact on quality of life in a primary care COPD population
COPD and obstructive sleep apnoea (OSA) are both associated with reduced quality of life. Previous studies have estimated the prevalence of OSA among patients with moderate to severe COPD, but little is known about the impact on quality of life in a milder, primary care population. We describe the characteristics of COPD patients stratified by sleep apnoea, and assess differences in quality of life in a primary care cohort.
Baseline data from the Birmingham COPD Cohort study was used to describe the proportion of COPD patients with OSA. A multivariable regression model (adjusted for age, sex, smoking status, severity of airflow obstruction and number of co-morbidities) was used to determine the association between OSA and CAT score amongst COPD patients. COPD was defined using the lower limit of normal (GLI equations), based on spirometry data from the Cohort baseline assessment. OSA was defined as being high risk on the Berlin Sleep Apnoea Questionnaire.
Among patients with COPD (n=1037), 48.2% also had OSA. These patients were younger and more likely to be obese and have a positive smoking history compared to those without OSA. Those with COPD and OSA reported higher CAT scores (mean difference 4.2, 95% CI 3.03 to 5.30), signifying greater impact on their daily lives.
OSA is common amongst patients with COPD in primary care. COPD patients with OSA reported clinically significantly worse quality of life than those without OSA, suggesting that associations previously found in more severe COPD patients are also present in those managed within primary care.