Defining trajectory in severe asthma: can it be changed?

Extract

The intrinsic variability of asthma across time is a well-known feature of the disease and stratifying disease severity is an integral component of asthma management [1]. Severe asthma is estimated to comprise up to 10% of the asthmatic population and is associated with substantial socioeconomic burden, with more than half of asthma-related healthcare costs being attributed to this level of severity [2–4]. It is associated with recurrent symptoms, increased risk for exacerbations, loss of lung function, fixed airflow obstruction and adverse side-effects of corticosteroids [5–9]. Despite this significant burden, and even though phenotypic changes from childhood to early adulthood have been previously described, little is known about the longitudinal trajectory towards severe asthma in adulthood [10, 11]. Chen et al. [12] performed a retrospective study on 13 467 asthma patients and found that 10 years after new-onset severe asthma, 83% of them had transitioned into a mild-to-moderate level of severity. A prospective cohort study aiming to characterise the long-term trajectory of mild asthma in 125 patients aged >16 years found that 92% of patients remained in the mild state over the following 10 years, and that inappropriate use of rescue therapy, older age and comorbidity were independently associated with an increased risk of progression from mild asthma [1]. However, a different progression trend was described by Haselkorn et al. [13], who found that approximately 50% of patients with severe or difficult-to-treat asthma had very poorly controlled asthma after more than 10 years of follow-up.