Adherence to inhaled corticosteroid use and local adverse events in persistent asthma

Abstract

Objectives: To measure adherence to inhaled corticosteroid (ICS) therapy using prescription claims and a patient survey, to identify local adverse events (LAEs) from the patient perspective and from medical records, and to evaluate the association between LAEs and adherence to ICS therapy.

Study design: Survey administration and claims-based and medical record-abstracted data.

Methods: Patients aged 6 to 64 years with persistent asthma (defined using an established algorithm) and at least 2 ICS prescriptions were selected from a claims database (1999-2006) of a central Massachusetts medical group practice. Prescription claims were used to calculate the ICS medication possession ratio (MPR). A survey obtained information about patient-reported adherence to ICSs using the Morisky scale and a visual analog scale (VAS) and about LAEs using the validated Inhaled Corticosteroid Questionnaire. Medical records of survey respondents were abstracted for LAEs.

Results: Among 372 survey respondents, 2.7% met the claims-based measure of good adherence (MPR, > or =80%). Patient-reported adherence was much higher; 20.7% of patients were highly adherent based on the Morisky scale (score, 0) and 55.4% based on the VAS (score, > or =80%). Medical record review identified 27.2% of patients having at least 1 LAE within 1 year after the ICS index date, but 47.3% of patients reported being bothered at least "quite a lot" by LAEs. Multivariate analysis indicated that unpleasant taste was significantly related to lower adherence based on the Morisky scale (P = .02).

Conclusions: Patient-reported adherence and LAEs were higher than those measured from claims or medical records. Unpleasant taste seems to be associated with lower adherence based on the Morisky scale.