| The purpose of this study was to develop and test psychometric instruments for the Medication Adherence Model constructs (Purposeful Action, Patterned Behavior, and Feedback). The study was conducted in three phases. Phase I undertook clarity and content validity evaluations of the items by 5 healthcare professionals and 5 individuals with hypertension. Phase II selected the final items and subscales by undertaking item analysis, internal consistency, and factor analysis with a sample of 227 individuals with hypertension. Phase III determined the temporal stability and construct validity estimates for the final Medication-Taking Questionnaires using the Phase II sample. The temporal stability sample totaled 116 individuals, and the construct validity sample totaled 111 individuals.; Four Medication-Taking Questionnaires were finalized and tested. The Medication-Taking Questionnaire, representing Purposeful Action, consisted of 13 items and 2 subscales (perceived benefits of treatment and perceived as safe). The Medication-Taking Questionnaire representing Patterned Behavior consisted of 16 items and 4 subscales (regularity of lifestyle, medication routine, remembering to take medications, and financial access to medications). Feedback was represented by 2 separate scales: (a) Medication-Taking Questionnaire: Positive Feedback (8 items) and (b) Medication-Taking Questionnaire: Negative Feedback (4 items).; The construct and divergent hypotheses were supported for the Medication-Taking Questionnaire: Patterned Behavior, suggesting that benefits and safety of treatment were being measured. Validity estimates were not supported for the Patterned Behavior and Feedback constructs, but results were possibly confounded due to the lack of similar measures. However, the results suggest that medication-taking patterns may be independent of general lifestyle routines and busyness. Medication-Taking Questionnaire: Positive Feedback appeared to represent the perceived benefits of medication-taking, and the Medication-Taking Questionnaire: Negative Feedback appeared to represent the perceived severity of an individual's hypertension.; Results provided preliminary support for the Medication Adherence Model depiction that intention to take medications and medication-taking patterns are contributors to being adherent to hypertension medications. Further studies using the Medication-Taking Questionnaires are needed to test the Medication Adherence Model and improve the questionnaires. Continuing examination of the Medication-Taking Questionnaires has the potential to contribute to the development of effective medication adherence interventions. |
