BREATHEIN: Better understanding obstructive REspiratory Airway disease Treatment and HEalth: a nationwide INvestigative survey in Denmark-a study protocol.

Abstract

Understanding patient perspectives on asthma and chronic obstructive pulmonary disease (COPD) is limited, with no prior studies employing such a large-scale, proactive survey to systematically target individuals with a confirmed prescription for inhalation medication. This study aims to explore how patients with asthma or COPD manage their lives, including treatment experiences, symptoms and impacts on daily life. A nationwide survey will be launched in January 2025, targeting adults (≥18 years) in Denmark diagnosed with asthma or COPD and prescribed or dispensed inhalation medication between 1 October 2023 and 30 September 2024. Data from the Danish Health Data Authority's Register of Medicinal Product Statistics will identify eligible individuals. The electronic survey will be distributed via e-Boks to approximately 450 000 individuals.The questionnaire integrates validated tools-COPD Assessment Test, Modified Medical Research Council scale, EuroQol 5-Dimension 5-Level and Asthma Control Test-alongside expert-developed questions on symptoms, diagnosis, disease control, treatment and patient experiences. Questionnaire development included 10 cognitive interviews with patients from the Outpatient Clinic at Vejle Hospital.Descriptive statistics will be used to analyse both continuous and categorical data, with sensitivity analyses conducted as well. Data management will be handled in Research Electronic Data Capture, and statistical analyses will be performed using Stata V.18.0. The study is registered with the Danish Data Protection Agency (24/5229) and Open Patient Data Explorative Network (OP_2094) and follows the Declaration of Helsinki. Results will be published in peer-reviewed journals, presented at national and international conferences and shared through patient associations.