Factors associated with adherence to asthma treatment with inhaled corticosteroids: A cross-sectional exploratory study

Background: Understanding factors at the patient, provider or organizational level associated with inhaled corticosteroids (ICSs) adherence is important when planning adherence-enhancing interventions. Objective: To explore factors associated with adherence to ICS among patients with asthma aged 12-45years. Methods: A cross-sectional study was conducted among patients with asthma reporting ICS prescription during the baseline interview of an intervention study. Three methods were used to measure ICS adherence: a 4-item self-report questionnaire, a single question (SQ) measuring past 7-day exposure to ICS and a medication possession ratio (MPR, i.e., the sum of ICS days of supply/365). We assessed 46 potential factors of ICS adherence derived from the Predisposing, Reinforcing and Enabling Constructs in Educational Diagnosis and Evaluation (PRECEDE) model. Their association with ICS adherence was measured using multivariate logistic regressions. Results: Among the 319 participants included, 16.0% were deemed adherent according to the 4-item questionnaire. This proportion was 43.0% and 9.1% for the SQ and the MPR method, respectively. Ten factors were associated with good ICS adherence. Among these factors, four were associated with adherence through one of the measuring methods: a low family income level, a high number of asthma drugs used, a good knowledge of asthma pathophysiology and the perception that following the ICS prescription was easy. Two factors emerged through more than one measure: perceiving asthma severity as moderate to very severe and perceiving a high risk of death if ICSs are not taken as prescribed. Conclusion: ICS adherence was poor in those individuals with asthma. Future adherence-enhancing interventions could target the identified modifiable risk factors.