Box 1.

Asthma Characteristics as Defined in the Dutch GP COPD Guideline and the Operationalization Based on the Available AC-Service Data

According to Dutch GP COPD guideline6	Data available in AC-service data
History of asthma “Anamnestic suspicion of asthma: a history of asthma”	Patient-reported history of asthma
Symptom pattern “Anamnestic suspicion of asthma: the nature of the symptom pattern”	Question 1 of the Asthma Control Questionnaire is regarded as the most typical asthma sign: “Nighttime awakenings”
Atopy of the patient or in first-degree family members “Anamnestic suspicion of asthma: Atopy of the patient or in first-degree family members”	A combination of different variables of the data set: Self-reported atopy: Patient-reported responsiveness for the following triggers: House-dust mites, food, grass pollen, tree pollen, animal dander, and seasonal change. Self-reported history of atopy: History of: Allergic Rhinitis Allergy Eczema Atopy of first-degree family members: Not available in this data set
Reversibility “Increase in FEV1 of ≥ 12% and ≥ 200 mL compared to the FEV1 prior to bronchodilatation suggestive for asthma”	Increase in FEV1 of ≥ 12% and ≥ 200mL compared to the FEV1 prior to bronchodilatation

Abbreviations: GP, general practitioner; COPD, chronic obstructive pulmonary disease; AC service, asthma/COPD service; GOLD, Global Initiative for Chronic Obstructive Lung Disease; FEV1, forced expiratory volume in 1 second.