Patient nonadherence to medication regimens is associated with worse outcomes and substantial economic cost. Although estimated nonadherence is generally high in patients with chronic diseases (50%), rates are especially elevated in those with chronic obstructive pulmonary disease (COPD) and asthma (70%-80%).1,2

In a recent review published in the Journal of Allergy and Clinical Immunology, the authors examined the causes and consequences of nonadherence in patients with asthma and COPD, as well as potential interventions to increase adherence.3 “Despite the advances in respiratory care that have been introduced over the last 50 years, suboptimal control still accounts for a large proportion of the costs incurred by asthma and COPD,” the review authors wrote. “It is therefore time to address the underlying problem of nonadherence and make better use of available resources.”

Nonadherence rates are higher for inhaler use compared with oral, injected, and transdermal routes of administration. The causes can be intentional (such as denial of diagnosis, social embarrassment, or concern about potential adverse events) or unintentional (unwitting poor inhaler technique, misunderstanding about when to use it, and forgetfulness).4 For patients with COPD, adherence may be further influenced by the older age of this group, which confers a greater risk for cognitive dysfunction, comorbidity, and polypharmacy.5

In a retrospective analysis of 3981 patients in the United Kingdom, rates of uncontrolled asthma were nearly 4-fold in those individuals who failed an inhaler technique test, compared with those who passed the test.6 A retrospective study conducted in the United States reported that greater adherence to inhaled corticosteroids could have prevented approximately 24% of asthma exacerbations.7

In addition, an observational study by Italian researchers demonstrated a significant link between inhaler-handling errors and increased risk for emergency department visits (P <.001), hospitalization (P =.001), courses of oral corticosteroids (P <.05), and use of antibiotics (P <.001).8 In terms of economic cost, other findings indicate that an estimated $7 billion to $17 billion is wasted annually in the United States as a result of inhaler misuse.9