Effects of a Health Literacy-tailored Self-management Intervention on People With Hypertension

Participants' blood pressure levels will be measured using a validated digital sphygmomanometer.

the number of participants with optimal blood pressure control at each measurement time point divided by the total number of patients enrolled in the group

The Vietnamese General Medication Adherence Scale (GMAS) will be used to measure medication adherence across 11 items covering forgetfulness, intentional skipping, complex regimens, and cost-related non-adherence. Items are rated on a 4-point Likert scale from 0 (Strongly disagree) to 3 (Strongly agree), with total scores 0-33; higher scores indicate better adherence. In addition, pill count (the number of pills not used compared to the number of pills received at the most recent prescription filling) will be used as an objective measurement to confirm medication adherence among participants.

The Vietnamese version of the Hypertension Self-Care Profile Behaviour Scale (HT-SCPB) will be used to measure self-management behaviour. It includes 20 items that address different aspects of self-management behaviour: checking BP, regular visits to doctors, medication adherence, and lifestyle modifications. Each item will be rated on a 4-point Likert scale from 1 (never/rarely) to 4 (always). The total score 20-80, with a higher score indicating higher hypertension self-management behaviours.

The Vietnamese version of the Self-Efficacy for Managing Chronic Diseases (SEM-CD) scale will assess self-efficacy across six items, including confidence in managing fatigue, pain, emotional distress, other symptoms, health-related tasks, and actions beyond medication. Items are rated on a 10-point Likert scale from 1 (not at all confident) to 10 (totally confident), with the mean score (1-10) representing overall self-efficacy.

The 12-item Vietnamese Short-Form of Health Literacy Questionnaire (HLS-SF12) will be used to measure HL levels (Duong et al., 2019). It includes twelve items that assess how easy it is for patients to find (4 items), understand (3 items), appraise (3 items) and apply health information (2 items). Each item will be rated on a 4-Likert scale (from 1= "Very difficult" to 4="Very easy"). The total score of the scale will be calculated by the formula HL Index = (Mean-1) x (50/3), where Mean is the average score of the 12 items. The HL Index ranges from 0 to 50; a higher score indicates better HL.