Assessing Adherence by Combining the Test of Adherence to Inhalers with Pharmacy Refill Records.

Abstract

BACKGROUND AND OBJECTIVE\nThe Global Initiative for Asthma (GINA) recommends the concurrent use of self-report and pharmacy refill data to assess treatment adherence. However, clinical evidence to support this combined approach is limited. Objective: To determine non-adherence to inhaler medication based on a validated questionnaire (Test of Adherence to Inhalers; TAI) and prescription refill data in a community sample of patients with chronic obstructive pulmonary disease (COPD) or asthma. Secondarily, we sought to determine the degree of concordance between these two measures.\n\n\nMETHODS\nCross-sectional, observational multicentre study in patients with asthma or COPD. Sociodemographic and clinical data were obtained from clinical records. Refill data were retrieved from electronic pharmacy databases. Participants completed the 12-item TAI during a single visit as part of routine care. Non-adherence was defined as TAI < 50 or < 80% pharmacy refill rate (PRR) in the last six months.\n\n\nRESULTS\nA total of 816 patients (mean age, 60) were included. Non-adherence rates were 58.1% (TAI) and 28.6% (PRR) versus 64.6% for the combined data (p<.0001). Concordance between the two measures was weak (Cohen´s kappa=0.205).\n\n\nCONCLUSIONS\nThese findings confirm the GINA recommendations, indicating that concomitant use of the TAI and pharmacy refill data identifies a higher percentage of non-adherent asthma or COPD patients than either instrument alone.