Does inhaler adherence really matter in severe asthma?

Inhaled therapies, primarily the inhaled corticosteroid (ICS), have been the cornerstone of asthma treatment since the 1960s. They have been shown to reduce symptom burden, morbidity and mortality, and potentially avoid unnecessary and unscheduled healthcare. However, some people have severe asthma, defined by an inability to gain or maintain consistent disease control despite appropriate use of high dose ICS-containing inhalers. In this review, we discuss whether it is appropriate to demand adherence to a treatment this cohort are demonstrably resistant to.