ABSTRACT
Introduction: Clinical guidelines recommend the combined use of "self-completed questionnaires such as the Test of Adherence to Inhalers (TAI)" and the pharmacy refill rate (PRR) to determine adherence, but evidence based on comparative studies to support these recommendations is limited. Our objective was to determine adherence to inhalers in asthmatic patients, using the TAI and the PRR, as well as the correlation and concordance between both methods. Methods: Multicentre cross-sectional study including the first 196 consecutive adult asthmatic patients, of whom 183 were on maintenance treatment with Inhaled Corticosteroids (ICS). Nonadherence was defined as TAI < 50 or PRR < 80% in the previous 12 months. Results: A statistically significant positive correlation was observed between TAI and PRR scores (Spearman's rho coefficient = 0.185; p = 0.012). Prevalence of nonadherence based on TAI was 73.22%; 95%CI (66.54-79.91) and 57.92%; 95%CI (50.50-65.35) based on PRR was. In terms of agreement, a Cohen's kappa index = 0.174 and an overall % agreement of 61.7% were obtained. Twenty-two of the 49 patients who scored 50 on TAI (44.9%) refilled < 80% of inhalers. In contrast, 48 of the 134 patients who scored ≤ 49 on TAI (35.8%) refilled ≥ 80% at the pharmacy. Conclusions: Adherence remains suboptimal with prevalences of nonadherent patients > 50%. The concordance results supports, in line with guideline recommendations, that the use of both approaches (TAI and PRR) increases the ability to identify poor adherence compared to TAI or PRR alone.
