Factors related to intentional and unintentional medication nonadherence in elderly patients with hypertension in rural community.

PURPOSE: We assessed medication nonadherence, categorized as intentional or unintentional, and related factors in elderly patients with hypertension, correlating the data with measurement of blood pressure as the final target of medication adherence and other possible influencing factors, such as lifestyle.

PATIENTS AND METHODS: Subjects were aged ≥65 years, resided in a rural area, and were taking antihypertensive drugs. The survey was conducted in July 2014. Participants were divided into the following three groups: "Adherence", "Unintentional nonadherence", and "Intentional nonadherence". Individual cognitive components, such as necessity and concern as well as self-efficacy and other related factors, were compared according to adherence groups. The interrelationships between those factors and nonadherence were tested using structural equation modeling analysis.

RESULTS: Of the 401 subjects, 182 (45.6%) were in the adherence group, 107 (26.7%) in the unintentional nonadherence group, and 112 (27.9%) in the intentional nonadherence group. Necessity and self-efficacy were found to have a significant direct influence on unintentional nonadherence behaviors (necessity β=-0.171, P=0.019; self-efficacy β=-0.433, P<0.001); concern was not statistically significant (β=-0.009, P=0.909). Necessity was found to have significant direct and indirect impact on intentional nonadherence (direct β=-0.275, P=0.002; indirect β=-0.113, P=0.036). Self-efficacy had no significant direct effect on intentional nonadherence though it had the only significant indirect effect on intentional nonadherence (direct β=-0.055, P=0.515; indirect β=-0.286, P<0.001). Concern had no significant influence on intentional or on unintentional nonadherence (direct β=0.132 0.132, P=0.151; indirect β=-0.006, P=0.909).

CONCLUSION: Unintentional nonadherence should be regularly monitored and managed because of its potential prognostic significance. Interventions addressing cognitive factors, such as beliefs about medicine or self-efficacy, are relatively difficult to implement, but are essential to improve medication adherence.