The Effect of Motivational Interviewing on Knowledge, Self-Efficacy, and Treatment Adherence in Patients With Primary Hypertension Living in Semi-Rural Areas: A Randomized Controlled Trial

This study is a single-center, single-blind, parallel-group randomized controlled trial designed to examine the impact of a Health Belief Model (HBM)-based motivational interviewing (MI) intervention on knowledge level, self-efficacy, and treatment adherence among primary hypertension patients living in a semi-rural region. Hypertension, despite its typically asymptomatic course, is a prevalent chronic condition that contributes significantly to cardiovascular morbidity and mortality. Poor adherence to treatment and insufficient disease-related knowledge remain major barriers to achieving optimal blood pressure control. Self-efficacy is recognized as a crucial psychological determinant influencing lifestyle modification and medication adherence, and theoretical models-particularly the HBM-provide a structured framework for understanding individuals' health perceptions and facilitating behavioral change.

Motivational interviewing, a patient-centered counseling method aimed at strengthening intrinsic motivation, is thought to be particularly effective when combined with the HBM. The integration of these two approaches is expected to enhance individuals' readiness for change and promote active engagement in treatment. Existing evidence indicates that MI-based interventions can improve medication adherence, encourage lifestyle modifications, increase self-efficacy, and support better blood pressure control. These findings form the conceptual basis of the present study.

The trial was conducted between November 2025 and April 2026 at Hisarardı Family Health Center in Simav, Kütahya. The target population consisted of 140 individuals diagnosed with primary hypertension. Using G*Power with an effect size of 0.60, 80% power, and α=0.05, the required sample size was calculated as 50 participants per arm. Stratified randomization by sex and block randomization with blocks of four were employed.

The intervention group received a four-session MI program structured according to the HBM, consisting of the following components:

Enhancing risk perception and awareness of disease severity Highlighting treatment benefits and reducing perceived barriers Strengthening self-efficacy and developing a personalized action plan Strategies for maintaining behavioral change and identifying cues to action Each session lasted 30-45 minutes and was delivered biweekly. Participants in the control group did not receive any educational intervention and continued with routine clinical follow-up only.

Data were collected using the following instruments:

Hypertension Knowledge Level Scale Hill-Bone Medication Adherence Scale Hypertension Self-Efficacy Scale Systolic and diastolic blood pressure measurements Assessments were conducted at baseline (0 month), mid-intervention (3 months), and at the end of follow-up (6 months). Statistical analyses will be performed using SPSS 26.0, including paired and independent sample tests, correlation analyses, and effect size calculations.

Ethics approval, institutional permissions, and scale-use authorizations were obtained prior to data collection, and all procedures were carried out in accordance with the Declaration of Helsinki.

This study is expected to offer valuable insights into the applicability of theory-driven educational interventions in primary care settings, clarify the contribution of motivational interviewing to hypertension management, and inform national initiatives such as the Disease Management Platform (HYP).