Long-term adherence to inhaled corticosteroids and asthma control in adult-onset asthma

Abstract

Background: In short-term studies, poor adherence to inhaled corticosteroids (ICS) has been associated with worse asthma control, but the association of long-term adherence and disease control remains unclear.

Objective: To assess the relationship between 12-year adherence to ICS and asthma control in patients with adult-onset asthma.

Methods: As part of the Seinäjoki Adult Asthma Study, 181 patients with clinically confirmed new-onset adult asthma and regular ICS medication were followed-up for 12 years. Adherence (%) to ICS was assessed individually ((µg dispensed/µg prescribed)×100) during the follow-up. Asthma control was evaluated after 12 years of treatment according to the Global Initiative for Asthma 2010 guideline.

Results: Asthma was controlled in 31% and not controlled (partly controlled or uncontrolled) in 69% of the patients. Patients with not-controlled asthma were more often male, older, nonatopic and used higher doses of ICS than those with controlled disease. The mean±sd 12-year adherence to ICS was 63±38% in patients with controlled asthma and 76±40% in patients with not-controlled disease (p=0.042). Among patients with not-controlled asthma, those with lower 12-year adherence (<80%) had more rapid decline in forced expiratory volume in 1 s (-47 mL·year-1) compared to patients with better adherence (≥80%) (-40 mL·year-1) (p=0.024). In contrast, this relationship was not seen in patients with controlled asthma.

Conclusions: In adult-onset asthma, patients with not-controlled disease showed better 12-year adherence to ICS treatment than those with controlled asthma. In not-controlled disease, adherence <80% was associated with more rapid lung function decline, underscoring the importance of early recognition of such patients in routine clinical practice.

Conflict of interest statement

Conflict of interest: I. Vähätalo has nothing to disclose. Conflict of interest: H. Kankaanranta reports fees for lectures and consulting, costs for attending an international congress, and research grant to his institution from AstraZeneca; fees for consulting from Chiesi Pharma AB; fees for lectures and consulting, and costs for attending an international congress from Boehringer Ingelheim; fees for lectures and consulting from Novartis; fees for lectures from Mundipharma; fees for lectures and consulting, and costs for attending international congress from Orion Pharma; fees for consulting from SanofiGenzyme; and fees for lectures and consulting from GlaxoSmithKline, all outside the submitted work. Conflict of interest: L.E. Tuomisto reports costs for attending an international congress and costs for lecture from Boehringer Ingelheim, and costs for a lecture from AstraZeneca, outside the submitted work. Conflict of interest: O. Niemelä has nothing to disclose. Conflict of interest: L. Lehtimäki reports personal fees from AstraZeneca, Boehringer Ingelheim, Chiesi, Circassia, GSK, Novartis, Mundipharma, Orion Pharma, Sanofi and Teva, outside the submitted work. Conflict of interest: P. Ilmarinen reports a grant for analysis and write-up of a study, and a fee for a lecture from AstraZeneca; fees for lectures from Mundipharma and GlaxoSmithKline; and a fee for a lecture and for preparing presentation material from Novartis, all outside the submitted work.

Copyright ©ERS 2021.

Figures

FIGURE 1

Flow-chart of the study. ICS: inhaled corticosteroids; GINA: Global Initiative for Asthma; ACT: Asthma Control Test; AQ20: Airway Questionnaire 20.

FIGURE 2

Long-term adherence to inhaled corticosteroids (ICS) in patients with controlled and not-controlled asthma. a) The average 12-year adherence to ICS in study subgroups (mean±sd). Adherence >100% means that patients were dispensed more than a regular individually prescribed minimum dose of ICS. b) The average annual adherence (mean±sem) in patients with controlled and not-controlled asthma during the 12-year follow-up period. p-value represents difference in annual ICS adherence between not-controlled and controlled patients as defined by area under the curve method and independent-samples t-test. Significant difference was also seen when patients with COPD were excluded from the analyses (a) p=0.021 and b) p=0.019).

FIGURE 3

Schematic presentation of the changes in forced expiratory volume in 1 s (FEV1) (mL) during 12 years of follow-up in patients with not-controlled asthma and ≥80% or <80% adherence. Model based on group medians. At the year 0 patients were steroid-naïve and inhaled corticosteroid (ICS) treatment was initiated (diagnostic visit). Origin for lung function decline is the maximal point of lung function within 2.5 years after start of treatment.