Prevalence and Determinants of COPD in Spain: EPISCAN II.

Background: Two previous national epidemiological studies, IBERPOC in 1997 and EPISCAN in 2007, determined the COPD burden in Spain. Changes in demographics and exposure to risk factors demand the periodic update of COPD prevalence and its determinants.

Methods: EPISCAN II aimed to estimate the prevalence of COPD in the general population aged 40 years or older in all 17 regions of Spain. A random population screening sample, requiring 600 participants per region performed a questionnaire plus post-bronchodilator (post-BD) spirometry.

Results: A total of 12,825 subjects were initially contacted, and 9433 (73.6%) agreed to participate, of whom 9092 performed a valid spirometry. Baseline characteristics were: 52.6% women, mean±SD age 60±11 years, 19.8% current- and 34.2% former-smokers. The prevalence of COPD measured by post-BD fixed ratio FEV/FVC<0.7 was 11.8% (95% C.I. 11.2-12.5) with a high variability by region (2.4-fold). Prevalence was 14.6% (95% C.I. 13.5-15.7) in males and 9.4% (95% C.I. 8.6-10.2) in females; according to the lower limit of normal (LLN) was 6.0% (95% C.I. 5.5-6.5) overall, by sex being 7.1% (95% C.I. 6.4-8.0) in males and 4.9% (95% C.I. 4.3-5.6) in females. Underdiagnosis of COPD was 74.7%. Cases with COPD were a mean of seven years older, more frequently male, of lower attained education, and with more smokers than the non-COPD population (p<0.001). However, the number of cigarettes and pack-years in non-COPD participants was substantial, as it was the reported use of e-cigarettes (7.0% vs. 5.5%) (p=0.045). There were also significant social and clinical differences including living alone, previous respiratory diagnoses, more comorbidities measured with the Charlson index, greater BODE and COTE scores, cognitive impairment, and depression (all p<0.001).

Conclusions: COPD remains prevalent in Spain and frequently underdiagnosed.