New-Onset Asthma in Adults: What Does the Trigger History Tell Us?

Background: Adult-onset asthma is an important asthma phenotype and, in contrast to childhood asthma, is often associated with specific triggers of onset. It is unknown whether these triggers correspond with specific phenotypic characteristics or predict a specific asthma outcome. Objective: To compare clinical, functional, and inflammatory characteristics between patients with different triggers of asthma onset, and relate these triggers to asthma outcome. Methods: Two hundred adults with recently diagnosed (<1 year) asthma were prospectively followed for 5 years. The trigger of asthma onset was patient reported and defined by the question: “What, in your opinion, elicited your asthma?” Asthma remission was defined as no asthma symptoms and no asthma medication use for ≥1 year. Kruskal-Wallis and Fisher's exact test were used to compare categories containing >10 patients. Results: Ten categories of triggers were identified, of which 5 contained >10 patients. Clinical and inflammatory characteristics and remission rates differed significantly between categories. “New allergic sensitization” (11%) was associated with mild atopic asthma and a relatively young age at onset; “pneumonia” (8%) with previous smoking, low IgE, and the highest remission rates (one third); “upper respiratory symptoms” (22%) with high exhaled NO and eosinophilia; “no trigger identified” (38%) did not show any specific characteristics; and “stressful life event” (7%) with high medication usage, low type 2 markers, and no disease remission. Conclusions: Patients with adult-onset asthma can be characterized by the trigger that seemingly incited their asthma. These triggers might represent underlying mechanisms and may be important to phenotype patients and predict disease outcome.