Patients with mild asthma may also have persistent airflow limitation (PAL), which increases the risk of acute exacerbations, according to a post-hoc analysis of the ATLANTIS study published in the January 2023 issue of The Lancet Respiratory Medicine.

In this post-hoc analysis, Kole et al examined 760 patients, aged 18-65 years (mean age 44 years) from the ATLANTIS study and who had been diagnosed with asthma at least 6 months prior to their recruitment in the study. The ATLANTIS study was conducted in nine countries: Brazil, China, Germany, Italy, Spain, the Netherlands, the UK, the USA and Canada. Nearly two-thirds (58%) of the participants were women. PAL was defined as a post-bronchodilator FEV1/FVC below the lower limit of normal at study entry. Majority (76%) of patients were never smokers. Thirty-three percent were found to have persistent airflow limitation. Patients were grouped into two: 248 with asthma and PAL and 512 with asthma without PAL. Through this study conducted between June 2014 and March 2017, the researchers aimed to evaluate the impact of PAL in patients with asthma.

Results showed that 21 (16%) of 133 patients with GINA step 1 and 24 (29%) of 83 patients with GINA step 2 asthma also had PAL. At one year follow-up, PAL was associated with older age at baseline; 46 years in patients with persistent airflow limitation vs 43 years old in those without persistent airflow limitation. Male patients (51% vs 38%) and those with longer duration of asthma (24 years vs 12 years) were more likely to have PAL. A similar independent association was noted between PAL and  higher blood eosinophil counts (median 0·27 × 10⁹ cells/L vs 0·20 × 10⁹ cells/L), a higher prevalence of small airway dysfunction and greater number of exacerbations. “Associations between PAL, age, and eosinophilic inflammation were validated in the U-BIOPRED cohort, whereas associations with sex, duration of asthma, and risk of exacerbations were not validated”, write the authors.

This study shows that not just patients with severe asthma, but many patients with mild asthma also had PAL. These patients also had eosinophilic inflammation and were at a higher risk of exacerbations. These findings imply that patients with mild asthma also need careful monitoring for detection of PAL and those with PAL may require more aggressive treatment by increasing the dose of their current medications or add-on medications in order to prevent exacerbations.

Reference

1. Tessa M Kole, et al; ATLANTIS; U-BIOPRED; CADSET investigators. Predictors and associations of the persistent airflow limitation phenotype in asthma: a post-hoc analysis of the ATLANTIS study. Lancet Respir Med. 2023 Jan;11(1):55-64. doi: 10.1016/S2213-2600(22)00185-0.