Twenty years of inhaler therapy: A nationwide drug utilization study

AIMS: This study aimed to map nationwide trends and prescribing patterns in inhaler use from 2004 to 2023. In light of evolving clinical guidelines and attention to the environmental impact of inhalers within recent years, we also examined variation in prescribing behaviour and patient-level treatment choices. METHODS: Using nationwide health registries, we identified all individuals redeeming prescriptions for pressurized metered-dose inhalers (pMDIs), dry powder inhalers (DPIs) and soft mist inhalers (SMIs) in Denmark over the past 20 years. Analyses included trends in total use, new and chronic use, patient demographics, comorbidities, markers of disease severity and prescribing sector. Subgroup analyses stratified use patterns by inferred diagnosis (asthma vs. COPD) and repeated main analyses excluding children