Factors Affecting Adherence to Antihypertensive Medication: Results from a Rural Population Study in East of Iran

INTRODUCTION: Medication therapy is one of the most important interventions for the control of hypertension and its complications, but patient nonadherence to prescribed antihypertensive medication is a challenge. This study was conducted to measure medication adherence and examine its determinants in patients with hypertension in a rural population of Iran.

METHODS: This cross-sectional study was conducted on 422 patients with hypertension covered by the healthcare network of Bajestan, Razavi Khorasan Province, Iran. Medication adherence was measured by using the Persian version of the 8 items Morisky Medication Adherence Scale (MMAS-8). The Chi-square test and Spearman’s correlation coefficient were used to examine the relationship between the determinants of medication adherence in SPSS.

RESULTS: The mean age of the patients was 65.02±8.88 years. Of the total of 422 patients, 299 (70.9%) were female. Based on the MMAS-8, medication adherence was high in 39.6% of the patients, moderate in 10.9% and low in 49.5%. The variables that correlated significantly with the level of medication adherence included age (P=0.032), education (P=0.022), income (P=0.001), the satisfaction of patients-physician communication (P=0.006), physician based education (P= 0.003), occupation, time interval of physician’s consultation (P=0.001), medication regime complexity (P=0.001), medications meals frequency (P=0.001), side effects (P=0.081) duration of the disease (P=0.015), comorbidities (P=0.001), smoking (P=0.047), patient’s ability to read medication instruction (P=0.011), the patient’s beliefs about the effectiveness of medications (P=0.001) and the patient’s beliefs about the effectiveness of health system (P=0.001). The variables of gender (P=0.147), marital status (P=0.054), and distance problems to the health center (P=0.181) were not significantly correlated with the level of medication adherence.

CONCLUSION: The results of the present study revealed a low medication adherence in half of the patients with hypertension due to various personal and socioeconomic determinants as well as factors associated with the health system, therapy-related factors, disease-related factors and patient-related factors. Purposeful interventions therefore appear essential to improving medication adherence in rural populations with a focus on the effect of each determinant of medication adherence.