Validity and Reliability of a Questionnaire to Measure Adherence to Treatment by Patients with Cardiovascular Disease

Abstract

Objective: Develop and validate an instrument to measure adherence to pharmacological and non-pharmacological treatment on the part of patients diagnosed with cardiovascular disease, based on a theoretical reference supported by treatment adherence behavior and self-efficacy. Materials and methods: The process of facial, content and construct validity performed on the instrument is outlined in detail, as are the reliability tests. The instrument was subject to evaluation by six experts and 380 adults with different sociodemographic characteristics, before being applied to 145 patients who had been diagnosed with ischemic cardiovascular disease. Results: A questionnaire with 29 items, 6 dimensions, a Cronbach’s alpha of 0.837 and a score of 29-174 was obtained, indicating that the higher the score, the better the adherence. Conclusions: It is considered a useful instrument to determine therapeutic behavior in terms of adherence to treatment among patients with ischemic cardiovascular disease, since it is based on a theoretical construct that is founded on adherence behavior, on the one hand, and self-efficacy, on the other. The latter is a predictor of adherence behavior. This broadens the approach to measuring the phenomenon, including determining the abilities or capacity perceived by patients in order to complete a treatment.