Impact of a Theory-Based Intervention to Promote Medication Adherence in Patients With a History of Myocardial Infarction

Background Patient discontinuation of cardioprotective medications after a cardiac ischemic event commonly occurs early after hospital discharge. Theory-based interventions could be effective in promoting better patient self-regulation of health-related behaviors and positive intentions to adhere to the recommended medical regimen. Objective The aim of this study was to evaluate the potential efficacy and feasibility of a theory-based intervention to promote adherence to cardioprotective medications. Methods In this mixed-methods quasi-experimental study with 3 time points, we recruited 45 participants with a positive intention to adhere and a history of myocardial infarction. They were recruited in primary care units in Brazil. Data collection occurred in 2 waves (T-b and T-60). The intervention consisted of developing action and coping plans, delivered in a 30-minute face-to-face session, with face-to-face reinforcement at a 30-day interval. Quantitative data were submitted to descriptive, Wilcoxon, and McNemar analyses; qualitative data were submitted to content analysis. Results An increase in the proportion of patients adhering to medications at the end of follow-up was found (T-60 - T-b, +60.0%; P < .001). In addition, a significant reduction was found for blood pressure (T-60 - T-b, -8.6 mm Hg; P < .001), heart rate (T-60 - T-b, -6.6 bpm; P < .001), and low-density lipoprotein (T-60 - T-b, -6.2 mg/dL; P < .05). Qualitative results revealed that the intervention was feasible, with an attrition rate of zero. The intervention was found to be easy to apply to patients' daily lives, and there was adequate time for implementation. Conclusions Our data confirm the potential efficacy of a theory-based intervention on the promotion of adherence to cardioprotective medications and on the related clinical end points, as well as its feasibility in the clinical context (Universal Trial Number: U1111-1189-9967).