Relationship between age and bronchodilator response at diagnosis in adult-onset asthma

Possible variation in bronchodilator response (BDR) according to age at the diagnosis of adult-onset asthma is unknown. Our aim was to assess if BDR in FEV₁ is related to age at diagnosis of adult-onset asthma and how many subjects fulfill the 400 mL criterion of BDR, the suggested cut-off for asthma-like reversibility in asthma-COPD overlap (ACO).

A total of 1030 patients with adult-onset asthma were included; 245 from SAAS (Seinäjoki Adult Asthma Study, Finland) and 785 from COREA (Cohort for Reality and Evolution of Adult Asthma in Korea) cohorts. BDR in FEV₁ at the diagnosis of asthma was assessed. Patients were divided into groups based on age at asthma diagnosis: < 40, 40-59.9, and ≥ 60 years. The cohorts were analyzed separately.

BDR % in FEV₁ did not differ between the groups of different age at asthma diagnosis and no correlation between BDR and age was found. Of patients aged ≥40 years, only 18% (SAAS-cohort) and 5% (COREA-cohort) reached the 400 mL BDR in FEV₁. After exclusion of possible ACO patients, the results remained similar.

By using two large cohorts of steroid-naive patients with asthma, we have shown that BDR at diagnosis of asthma is constant over large age span range, and the limit of 400 mL in BDR in FEV₁ is rarely reached.

Seinäjoki Adult Asthma Study is registered at ClinicalTrials.gov with identifier number NCT02733016 .