The Treatment Adherence Perception Questionnaire (TAPQ) is a new, brief self-report instrument for assessing patient perceptions and attitudes regarding their own adherence to medical treatment plans. It includes 3 distinct scales: Perceived Behavior, Perceived Benefit, and Perceived Burden. In contrast with existing measures, the TAPQ was expected to have a clear factor structure; have good discrimination; and assess distinct types of perception, each of which has different patterns of association with interpersonal, personality, motivational, and emotional variables. Foundational work on the TAPQ (with 891 patients) included 5 quantitative scale development studies and 1 qualitative study. The present report focuses on results from a final validation study using 450 patients recruited via market research panels to complete online questionnaires. This study included a general medical sample and a sample of people with either diabetes or hypertension. A confirmatory factor analysis specifying strict measurement invariance across these groups produced a good fit. Analysis with item-response theory suggested that the scales on the TAPQ provide good discrimination across a wide range of experience levels. The 3 scales on the TAPQ each had distinct patterns of association with criterion variables regarding conscientiousness, health behavior, motivation, affect, type of diagnosis, and interpersonal communication with health-care professionals. These effects could not be explained by another existing measure of adherence or by a measure of response bias.
Public Significance StatementMedical patients often fail to follow recommended treatment plans and, consequently, suffer bad health outcomes. To allow researchers to study patient adherence to treatment plans, we developed a questionnaire that assesses how well patients believe they are adhering, how much they think treatment is beneficial, and how much they find it burdensome. Results suggest that each of these components is important for understanding treatment adherence.