Diagnosis of asthma in the community can be difficult. Various phenotypes have different triggers and clinical presentations.

Furthermore, asthma can be episodic or can follow a relapsing and remitting course, which further complicates attempts to arrive at a diagnosis. Studies suggest fewer than half of patients receive spirometry testing to confirm variable expiratory airflow limitation prior to diagnosis. Furthermore, the expected rate of spontaneous remission of adult asthma, allowing for complete cessation of asthma therapy, is unknown.

This prospective, multicentre cohort study from Canada aimed to determine whether asthma could be ruled out in newly diagnosed adults and whether they could be safely weaned off asthma medications. Participants had physician-diagnosed asthma established within the past 5 years.

Patients were excluded if they were using long-term oral steroids, were pregnant, breastfeeding or unable to perform diagnostic tests or had a smoking history >10 pack-years. All participants (n=613) were assessed with peak flow and symptom monitoring, spirometry and serial bronchial challenge tests, and those on daily medication had it gradually tapered off. Participants in whom asthma was ruled out were followed up over 1 year.

Asthma was ruled out in 203 (33%) of 613 study participants. 12 participants had cardiorespiratory conditions previously misdiagnosed as asthma. 181 participants continued to exhibit no evidence of asthma after 12 months. This group was less likely to have undergone testing for airflow limitation in the community at the time of initial diagnosis.

Among some adult patients with physician-diagnosed asthma, reassessing that diagnosis may be warranted.

Shawn D Aaron, Katherine L Vandemheen, J Mark FitzGerald, et al. JAMA 2017;317(3):269–79. http://jamanetwork.com/journals/jama/article-abstract/2598265