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

INTRODUCTION: 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. METHODS: 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). RESULTS: 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). CONCLUSIONS: 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.