Background and objectives: COPD and obstructive sleep apnea (OSA) share similar pathological processes and cardiovascular sequelae. Coexisting OSA in COPD - "overlap syndrome" - has worse prognosis than either condition alone, and appropriate treatment improves survival. Our objectives were to ascertain the frequency at which COPD coexists with the risk of OSA in Taiwan and to compare the risk factors, COPD symptoms, and life quality metrics between COPD subgroups with versus without risk of OSA.
Methods: We conducted a random cross-sectional national telephone survey of adults >40 years old in Taiwan. Participants fulfilling an epidemiological case definition of COPD completed a questionnaire to assess COPD symptoms and OSA risk, comorbidities, and performance of daily activities. Data from COPD cohorts with and without risk of OSA were analyzed and compared.
Results: Of 6,600 interviews completed, 404 subjects fit the epidemiological case definition of COPD - an overall prevalence of 6.1% in this national sample. Data on OSA risk were available for 292 of this COPD cohort, of whom 29.5% were at risk of OSA. Compared to those without risk of OSA, those with risk of OSA were significantly more likely to have hypertension or cardiovascular disease and diabetes, had significantly higher body mass index and COPD Assessment Test scores, and reported impaired work performance and leisure activities.
Conclusion: Among adults in Taiwan who fulfill epidemiologic criteria for COPD, 29.5% have coexisting risk of OSA. Comorbid hypertension or cardiovascular disease and diabetes are common and significantly more prevalent among the COPD population at risk of OSA than those who are not. OSA screening is warranted in patients with COPD with those risk factors that are more prevalent in COPD with risk of OSA than without, to target early interventions to reduce adverse cardiovascular sequelae from overlap syndrome.
Keywords: COPD; OSA; cardiovascular risk; coexistent; obstructive sleep apnea; overlap syndrome.