Determinants of Non-Adherences to Long-Term Medical Therapy after Myocardial Infarction: A Cross-Sectional Study

Abstract

Purpose: Non-adherence to medications can be classified as unintentional and intentional. The aim of this study was to establish the major determinants of each non-adherence in myocardial infarction (MI). We also evaluated the effects of non-adherences on healthy behaviors. Materials and Methods: We enrolled 510 patients >1 year after MI. Nonadherences classified as unintentional or intentional were measured by a self-reported questionnaire. Polynomial and multiple regression analysis were performed to evaluate the determinant of each type of nonadherences. Results: Among patients with nonadherence, 263 (70.7%) patients were unintentionally non-adherent while 109 (29.3%) patients were intentionally non-adherent. Psychological belief and attitude were important in unintentional non-adherence (Exp(beta) = 0.917, p = 0.050 for anxiety; Exp(beta) = 1.191, p = 0.001 for concerns). Beliefs about medications were the strongest determinant of intentional non-adherence (Exp(beta) = 0.812, p < 0.001 for necessity; Exp(beta) = 1.421, p < 0.001 for concerns). Anxiety was important determinant of intentional non-adherence (Exp(beta) = 0.889, p = 0.015). Conclusion: Psychological factors and beliefs about medication were important determinants of both types of non-adherence. Combined approaches targeting the beliefs about medications and psychological distress are needed to improve drug adherence in patients with MI.