Trends of COPD in Spain: Changes Between Cross Sectional Surveys 1997, 2007 and 2017

We aim to describe the changes in prevalence and risk factors associated to chronic obstructive pulmonary disease (COPD) in Spain, comparing three population-based studies conducted in three timepoints.

We compared participants from IBERPOC conducted in 1997, EPISCAN conducted in 2007 and EPISCAN II in 2017. COPD was defined as a postbronchodilator FEV₁/FVC (forced expiratory volume in 1s/forced vital capacity) ratio <0.70, according to GOLD criteria; subsequently, also as the FEV₁/FVC below the lower limit of normal (LLN).

COPD prevalence in the population between 40 and 69 years decreased from 21.6% (95% CI 20.7%-23.2%) in 1997 to 8.8% (95% CI 8.2%-9.5%) in 2017, a 59.2% decline (p<0.001). In 2007, the prevalence was 7.7% (95% CI 6.8%-8.7%) with an upward trend of 1.1 percentage points in 2017 (p=0.073). Overall COPD prevalence decreased in men and women, although a significant increase was observed in the last decade in females (p<0.05). Current smokers significantly increased in the last decades (25.4% in 1997, 29.1% in 2007 and 23.4% in 2017; p<0.001). Regrettably, COPD underdiagnosis was constantly high, 77.6% in 1997, 78.4% in 2007, and to 78.2% in 2017 (p=0.95), higher in younger ages (40-49 yrs and 50-59 yrs) and also higher in women than in men in all three studies (p<0.05).

We report a significant reduction of 59.2% in the prevalence of COPD in Spain from 1997 to 2017 in subjects aged 40-69 years. Our study highlights the significant underdiagnosis of COPD, particularly sustained in women and younger populations.