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

ABSTRACT

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.

KEYWORDS:

• Asthma
• asthma control
• exacerbations
• inflammation
• lung function
• mild-to-moderate asthma
• phenotype
• severe asthma

Acknowledgements

The authors thank Serge Simard for statistical analyses.

Declaration of interest

ME Boulay, C Pruneau-Pomerleau, F Deschesnes, H Villeneuve, and L Ringuette report no conflicts of interest. The authors alone are responsible for the content and writing of the paper. LP Boulet has the following potential conflicts of interest (last 3 years): Nonprofit Grants: Research funding provided to my center for participating in multicenter studies: These have mostly been performed in the context of the Canadian Network of Centres of Excellence “AllerGen” Projects: Altair, Amgen, Asmacure, AstraZeneca, Boehringer-Ingelheim, Boston Scientific, Genentech, GlaxoSmithKline, Novartis, Ono, Pharma, Schering, Wyeth. Support for Investigator Generated studies: Takeda, Merck, Boehringer-Ingelheim. Consulting/advisory boards: Astra Zeneca, Novartis, Methapharm. Royalties: Co- author for “Up-To-Date” card on occupational asthma. Patents: None. Nonprofit Grants for production of educational materials: AstraZeneca, GlaxoSmithKline, Merck Frosst, Boehringer-Ingelheim, Novartis. Speaking Activities: Lecture fees from AstraZeneca, GlaxoSmithKline, Merck, Novartis. Travel sponsorship to meetings for presentation of studies & Committees: Novartis, Takeda. Others: Member of the Canadian Thoracic Society Respiratory Guidelines Committee; Chair of GINA Guidelines Dissemination and Implementation Committee; Laval University Chair on Knowledge Transfer, Prevention and Education in Respiratory and Cardiovascular Health.

Additional information

Funding

This study was supported in part by Merck Canada (MCA-111122-005964).