Effectiveness of a Theory of Planned Behavior-Based Intervention for Promoting Medication Adherence among Rural Elderly Hypertensive Patients in Iran

Introduction: Medication adherence is regarded as one of the most important factors in caring for hypertension. This study aimed to investigate the effect of intervention based on the theory of planned behavior (TPB) on medication adherence and its influencing factors on the elderly with hypertension in a rural area, Kerman province, Iran.                  Methods: This quasi-experimental study of the pre and post-control type was conducted on 109 elderly patients with hypertension. Data were collected using a multistage random sampling and a valid questionnaire based on the TPB. The intervention was an educational program based on TPB constructs using educational videos, pamphlets and booklets approved by the Ministry of Health. The collected data were analyzed by the SPSS 22 using parametric tests (Independent t-test, paired t-test, and regression analysis). Results: The average score of the attitudes , perceived behavioral control, as well as medication adherence behavior  constructs increased significantly after the intervention in the intervention group compared to the control group (p < 0.001). Multivariate regression analysis in intervention group after intervention showed that 76% of variations in intention were explained by the model. Attitude, subjective norms and perceived behavioral control were independent predictors of intention. The association between subjective norms and intention was of marginal significance (B = 0.89). Conclusion: The results of this research showed that an educational program based on TPB can affect medication adherence on elderly rural patients suffering from hypertension.