This study aimed to determine COPD prevalence in Spain and identify the level of undiagnosis and the impact of undiagnosed COPD on health-related quality of life (HRQL) and activities of daily living (ADL).
We surveyed a population-based sample of 4,274 adults aged 40 to 80 years. They were invited to answer a questionnaire and undergo pre- and post-bronchodilator spirometry. COPD was defined as a postbronchodilator FEV1/FVC ratio of <0.70.
For 3,802 participants with good-quality postbronchodilator spirometry, the overall prevalence of COPD was 10.2% (95% confidence interval 9.2% - 11.1%) and was higher in men (15.1%) than in women (5.6%). The prevalence of COPD stage II or higher was 4.4% (95%CI; 3.8%-5.1%). The prevalence of COPD increased with age and with cigarette smoking and was higher in low educational levels. A previous diagnosis of COPD was reported by 27% of COPD cases only. Diagnosed patients had more severe disease, higher cumulative smoking consumption and more severely impaired HRQL compared with undiagnosed subjects. However, even patients with undiagnosed COPD stage I+ already showed impairment in HRQL and in some aspects of ADL compared with participants without COPD.
The prevalence of COPD in individuals between 40 and 80 years of age in Spain is 10.2% and increases with age, smoking consumption and lower educational levels. The rate of undiagnosis is very high and undiagnosed individuals with COPD already have a significant impairment in HRQL and ADL.