Introduction: Obstructive airway diseases, primarily COPD and asthma, are highly prevalent worldwide. In this abstract we explore the prevalence of individuals treated for obstructive airway disease in the Danish population.

Method: Using nationwide Danish registry data on all Danish citizens, individuals were included at birth, in 5-year intervals from age 5 till age 90, from 1 January 2015 till 31 December 2019. The national prescription registry (NPR), with data available from the 1 January 1995, was used to identify previous medication use. Present obstructive airway medication use (OAM) use was defined as medication use one year prior to inclusion (ATC R03). Past use was defined as any time point during NPR?s existence, creating a maximum of 20 years and a minimum of 15 years of prescription information.

Results: A total of 5,919,024 were included with 50.1% females. In total 1,941,807 (32,8%) had been prescribed OAM. Present OAM use was found in 429,473 (7,3%) and past OAM use, excluding current users, was seen in 1,512,334 (25,6%) individuals. Current OAM users is high at 5 years (7.7%) declining to a minimum at age 25 (3.3%) and then rising with age till age 85 (16.5%). Past users peak at age 15 (47.7%) declining until the age of 35 (16.1%) and again increasing until age 55 (25.3%) (see figure 1).

Conclusion: OAM use is high in the Danish population, with however many who have used OAM previously but discontinuous this.