Application of the Health Belief Model Using the PRECEDE-PROCEED Framework for Community-Based Hypertension Control: A Cluster Randomized Trial

Hypertension is a leading modifiable risk factor for cardiovascular disease, stroke, chronic kidney disease, and premature mortality worldwide, with a particularly high burden in low- and middle-income countries where awareness, treatment, and control remain suboptimal. In Bangladesh, national surveys indicate that approximately one in four adults has hypertension and fewer than half of treated individuals achieve adequate blood pressure control, reflecting gaps in medication adherence, lifestyle behaviours, and continuity of care. Formative mixed-methods research in the study area documented a high prevalence of uncontrolled hypertension despite widespread treatment, low adherence to antihypertensive medications, high dietary salt intake, low fruit consumption, physical inactivity, prevalent tobacco use, and fragmented care pathways that rely heavily on informal providers.

The Health Belief Model is a widely used theoretical framework for understanding and modifying preventive and treatment behaviours and posits that action is influenced by perceived susceptibility, severity, benefits, barriers, cues to action, and self-efficacy. The PRECEDE-PROCEED model provides a comprehensive planning and evaluation framework that links social, epidemiological, behavioural, and environmental assessments to educational, organisational, and policy strategies. Building on detailed formative work in rural and peri-urban communities in northeastern Bangladesh, this trial applies the Health Belief Model within the PRECEDE-PROCEED framework to design and evaluate a multicomponent, community-based educational intervention targeting key determinants of poor hypertension control.

This is a parallel-group, community-based cluster randomized controlled trial conducted in Kamalgonj Upazila, Moulvibazar district, Bangladesh. Clusters are defined as villages or wards with a population of approximately 3,000-5,000 residents and clear geographic boundaries; twelve clusters (six intervention, six control) are selected from an administrative sampling frame in collaboration with local health authorities and randomly allocated (1:1) to intervention or usual-care control after baseline data collection, stratified by urban-rural status. Adults are eligible if they are aged 18 years or older, have physician-diagnosed hypertension or documented systolic blood pressure 140 mmHg or higher or diastolic blood pressure 90 mmHg or higher on at least two screening occasions, have resided in the cluster for at least six months with no intention to move during the study period, and are able to provide informed consent; individuals with severe cognitive impairment, serious comorbidities requiring intensive care, or current or planned pregnancy within 12 months are excluded. The planned sample size is approximately 480 participants (about 40 per cluster), providing 80 percent power to detect a between-group difference of 5-7 mmHg in mean systolic blood pressure at 12 months, assuming a standard deviation of 20 mmHg, an intracluster correlation coefficient in the range 0.02-0.05, and up to 15 percent loss to follow-up.

The intervention is delivered over 12 months by trained community health workers using four integrated components grounded in Health Belief Model constructs and informed by the PRECEDE assessment. First, group education consists of four biweekly sessions (45-60 minutes each) conducted in community venues such as non-governmental organisation offices and uses interactive lectures, visual aids, group discussions, and role plays to address understanding hypertension and its complications, benefits of blood pressure control, medication adherence and management of side effects, and lifestyle modification including salt reduction, physical activity, healthy diet, and tobacco cessation. Second, individual counselling and motivational interviewing involve two one-to-one sessions (approximately 20-30 minutes each, at weeks 4 and 8) in which community health workers identify personal barriers such as cost, fear of side effects, low family support, and competing priorities, negotiate specific, measurable, achievable, relevant and time-bound behaviour change goals, and support self-management planning. Third, enabling strategies include establishing community blood pressure monitoring points with validated automated devices, providing simple pictorial educational materials in Bengali, medication reminder calendars, and wallet cards, sending periodic mobile phone reminders where feasible, and facilitating linkages to affordable antihypertensive medicines through government essential drug programmes and local pharmacies. Fourth, reinforcing strategies engage family members in at least one group session, promote informal peer support such as walking groups, provide regular follow-up contacts including monthly calls or home visits during months 3-12, and offer recognition for participants who achieve or maintain blood pressure control or demonstrate sustained behaviour change to strengthen social norms supportive of healthy behaviours.

Control clusters receive usual care available through existing government and private health services without additional theory-based educational or community mobilisation activities. All participants in both arms undergo data collection at baseline (before randomization), 6 months, and 12 months, conducted by trained interviewers and outcome assessors who are blinded to allocation where feasible. Blood pressure is measured using standardized procedures with validated automated oscillometric devices, with participants seated for at least 5 minutes and two readings taken 1-2 minutes apart on the same arm and averaged. Interviewer-administered questionnaires capture socio-demographic characteristics, scores on Health Belief Model constructs using a validated 38-item scale, medication adherence using a nine-item Bangladesh Medication Adherence Scale, lifestyle behaviours including salt use, physical activity, fruit and vegetable intake and tobacco use, hypertension knowledge, and health service utilisation including frequency and source of blood pressure monitoring and clinic visits.