Objective: Despite the importance of the chronic use of inhaled corticosteroids (ICS) in maintaining asthma control, reported adherence varies between 40% and 60%. The Beliefs about Medicines Questionnaire (BMQ) has been shown to correlate with self-reported adherence. The aim of this study is to investigate whether beliefs about ICS (necessity and concerns), as measured by the BMQ, relate to adherence objectively measured by prescription-refill records.
Methods: In a cross-sectional study of patients aged 18-45 years who filled at least two ICS prescriptions in 11 community pharmacies in The Netherlands, perceptions of ICS were assessed using the BMQ. Additionally, self-reported adherence was assessed using the Medication Adherence Report Scale. ICS prescription-refill adherence rates for a 12-month period prior to the survey were obtained from automated pharmacy dispensing records. Four attitudinal groups were defined using the necessity and concerns constructs. Statistical tests were used to examine associations between ICS adherence (assessed by subjective self-report and objective pharmacy records), specific beliefs about and attitudes towards ICS, and more general beliefs about pharmaceuticals.
Results: Questionnaires were returned by 238 patients (51.1%). Both self-reported adherence (r=.38) and adherence by pharmacy records (rho=0.32) correlated with ICS necessity beliefs and concerns. Patients defined as skeptical, indifferent, ambivalent, or accepting, on the basis of these constructs, differed with respect to both their attitudes towards medicines in general and their adherence to medication.
Conclusions: Patients' beliefs about ICS correlate not only with adherence by self-report but also with a more objective measure of medication adherence calculated by pharmacy dispensing records. The necessity-concerns constructs offer a potentially useful framework to help clinicians elicit key treatment beliefs influencing adherence to ICS.