Correlates of Barriers to Medication Adherence in Patients with Coronary Artery Disease

Adherence to medications can effectively reduce the recurrence of mortality, myocardial infarction or cardiovascular events in patients with coronary artery disease. However, around 50% of the patients do not adhere to medication. The purpose of this study was to explore the predictors of barriers to medication. A cross-sectional, descriptive correlational research design was used, and a non-probability sample of 250 participants was recruited from the cardiology outpatient department and ward of a medical center located in southern Taiwan. Inclusion criteria were as follows: (1) being 20 years or older, (2) having a diagnosis of CAD (ICD-9-CM Diagnosis Code 410-414) as determined by cardiologists, (3) having received CAD medications for at least three months, (4) being able to communicate either by Mandarin or Taiwanese, and (5) willing to participate in this study. The instruments included demographic data, medication-related variables, Cardiac Symptom Survey, Charlson Comorbidity Index, and Medication Adherence Scale (knowledge, attitude, and barriers). Data were analyzed using SPSS version 20.0 for Windows and SAS version 9.3. A tobit regression was conducted to identify significant predictors of barriers to medication adherence.

The results showed that the majority of the participants had high medication adherence with a mean knowledge dimension score of 1.92 (range, 0-3), a mean attitude dimension score of 26.71 (range, 11-30), and a mean barriers dimension score of 5.90 (range, 0-68). The significant predictors of barriers to medication adherence included poor attitude (p < .0001), younger age (p = .012), employment (p = .016), irregular follow-up (p = .041), and cardiac symptoms (p = .037).  Findings from this study can provide nurses as references to early detect and prevent barriers to medication adherence of the patients. It can be done by strategies such as, reviewing the patient’s prescribed medications by a physician in order to simplify the medication use and monitoring the side effects of medications by nurse specialists. Likewise, merely 21.2% of the participants had been received a comprehensive medication counseling. Implementing comprehensive medication counseling services is particularly needed to help improve medication adherence of the patients.