Comparative features of Asthma with frequent or infrequent exacerbations: A longitudinal study of retrospective and prospective events.

Background: A "frequent exacerbator phenotype" has been described, mostly in the population of patients with severe asthma. Further data are needed on such exacerbation-prone patients in milder asthma.

Aim: To compare the characteristics of frequent and nonfrequent exacerbators in asthma of different severities and to assess the stability of the exacerbator status.

Methods: This was an observational study comparing baseline data from frequent (≥2 exacerbations in the past year) and nonfrequent (<2 exacerbations in the past year) exacerbators. Patients were also followed up for one year. Information regarding clinical, physiologic, and inflammatory characteristics was collected at baseline and one-year follow-up.

Results: Forty-seven frequent and 53 nonfrequent exacerbators were recruited. No specific clinical, physiologic, or inflammatory characteristic was observed in the frequent as compared to the nonfrequent exacerbators at baseline. Fifty-eight percent of patients reporting frequent exacerbations at baseline remained in this group after one year of follow-up. Forty-two and 62% of patients with, respectively, mild-to-moderate asthma and severe asthma had frequent exacerbations. In a post hoc analysis according to asthma severity, frequent exacerbators with severe asthma had a higher body mass index and poorer asthma control, although they reported higher adherence to medication, in comparison to frequent exacerbators with mild-to-moderate asthma. No specific characteristics could discriminate between frequent and nonfrequent exacerbators of the same asthma severity.

Conclusions: Frequent exacerbators with severe asthma present some specific characteristics not observed in frequent exacerbators with mild-to-moderate disease. However, the latter group should be identified to reassess treatment needs and potential contributing factors.