Salt Intake and Blood Pressure Control in Adults With Essential Hypertension
Trial Snapshot
- Phase
- Not Applicable
- Status
- Not yet recruiting
- Sponsor
- Enrollment
- 190
- Primary Endpoint
- 24 hour Urinary Sodium level
Study Overview
Brief Summary
The goal of this study is to explore the barriers and facilitators to adopting a reduced dietary salt and increased potassium intake among adults with essential hypertension in Singapore, and to evaluate the feasibility and preliminary effectiveness of a newly developed educational tool-Decreased Salt High Potassium (DSHP) Diet Tool-in reducing dietary sodium intake and increasing potassium intake.
This three-part study will involve adults aged 21 years and above, with a self-reported diagnosis of hypertension for at least six months and/or currently taking antihypertensive medication. Participants will be recruited from two SingHealth Polyclinics (Punggol Polyclinic and Pasir Ris Polyclinic). Healthcare providers (HCPs) working at these clinics who have experience in managing patients with hypertension and in educating patients on reducing dietary sodium intake will also be recruited.
The main questions this study aims to answer are:
- What are the perceived barriers and facilitators for patients with hypertension to reduce dietary sodium and increase potassium intake?
- What are the perceived barriers and facilitators experienced by healthcare providers in educating patients about sodium reduction and potassium intake?
- Is the DSHP Diet Tool feasible and effective in reducing dietary sodium intake and increasing potassium intake among patients with hypertension?
Participants in the intervention group will be provided DSHP Diet Tool and Decreased Salt High Potassium patient information leaflet (DSHP PIL). Participants in the control group will receive standard care and a patient information leaflet (DSHP PIL). Researchers will compare participants in the intervention group to the control group to determine whether the DSHP tool is effective in reducing dietary sodium and increasing potassium intake in patients with hypertension.
Detailed Description
Hypertension is a major public health concern globally, contributing to cardiovascular disease and premature mortality. According to the World Health Organization (2023), one in three adults worldwide suffers from hypertension. In Singapore, the 2022 National Population Health Survey reported that over 35% of residents aged 18 to 74 years had hypertension, with nearly 65% of those under medical follow-up exhibiting poor blood pressure control. One of the most significant and modifiable risk factors for hypertension is diet-specifically, excessive sodium (salt) intake and insufficient potassium intake.
Excess sodium elevates blood pressure by causing fluid retention and adversely affecting vascular function. Conversely, potassium intake helps regulate blood pressure through mechanisms like promoting sodium excretion and reducing vascular resistance. The benefits of dietary sodium reduction and increasing potassium intake are well-established in both clinical trials and population studies, particularly in individuals with hypertension.
Despite this, Singaporeans continue to consume well above the recommended daily intake for sodium and below the optimal levels for potassium. The average sodium intake is approximately 3,620 mg/day (exceeding the WHO recommendation of 2,000 mg/day), while potassium intake averages 2,500 mg/day (below the recommended 3,510 mg/day). Public health initiatives like the "War on Salt" campaign (launched in 2011) have had limited long-term success in addressing these dietary gaps.
Previous studies in Singapore and neighboring countries have identified significant gaps in knowledge, attitudes, and behaviors related to dietary sodium and potassium. However, there has been limited research focused on practical, context-specific educational interventions aimed at improving dietary behaviors related to salt and potassium intake, especially within the hypertensive population in the primary care setting.
Study Objectives and Hypothesis This study is designed in three parts to systematically develop, refine, and evaluate a novel educational tool-the Decreased Salt High Potassium (DSHP) Diet Tool-for hypertensive patients. The tool aims to support patients in reducing dietary sodium and increasing potassium intake, thereby improving blood pressure control and overall cardiovascular risk profiles.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Parallel
- Primary Purpose
- Treatment
- Masking
- Double (Participant, Outcomes Assessor)
Masking Description
Participants will be masked to group allocation. While both groups will receive educational materials, participants in the control arm will not be informed that the Patient Information Leaflet (PIL) is the comparator intervention. This design minimizes expectancy bias by ensuring participants are unaware of whether they are receiving the "active" DSHP Diet Tool or the control material. Outcome assessors analyzing biochemical and clinical data will also be masked to group allocation to reduce detection bias.
Eligibility Criteria
- Ages
- 21 Years to — (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •for patients:
- •Participants who are 21 years old and above.
- •Participants who self-reports to have hypertension for at least six months and/ or taking at least one type of antihypertensive medication daily for at least six months
- •Able to read English
Exclusion Criteria
- •for patients:
- •Participants with type 1/ type 2 or secondary diabetes mellitus
- •Participants with CKD stage 3B and above
- •Participants with serum potassium of above 4.5mmol/L (on the latest blood test)
- •Participants with serum sodium of less than 135 mmol/L (on the latest blood test)
- •Participants who are on daily potassium chloride
- •Participants who are on diuretics (thiazide or thiazide like diuretics)
- •Participants who are pregnant
- •Participants who had been diagnosed with any terminal illnesses, visually impaired, disability or mental health related illnesses (visually impaired refers to individuals who self-report to have difficulty reading the wordings on the patient consent form, even with the use of visual aids)
- •Participants who are not clinically stable (Clinically stable patients are defined in this study as:
- •Has clinic BP 100-160/60-100 mmHg, Heart Rate (HR) 60-100 bpm
- •No recent hospitalizations (within the last 3 months) due to hypertensive emergencies, strokes, myocardial infarctions or other acute cardiovascular events
- •No recent symptoms such as severe dizziness, fainting, or chest pain) *Participants who are on PRN potassium supplements is not an exclusion criteria
- •Inclusion criteria for Healthcare providers:
- •HCPs who had prior experience in advising patients on dietary salt reduction
- •HCPs who self-reported to have ever treated patients with hypertension
- •Exclusion criteria for healthcare providers
Arms & Interventions
DSHP Diet Tool and DSHP Patient information leaflet
Participants in this arm will receive standard hypertension care along with access to the Decreased Salt High Potassium (DSHP) Diet Tool for 24 weeks and DSHP Patient information leaflet. The DSHP Tool is a patient-centered educational resource developed to support sodium reduction and increase potassium intake through practical strategies, goal setting, and food guidance. Participants will also receive the DSHP Patient Information Leaflet (PIL). Patients will be guided on how to use the tool by a study coordinator. Clinical and dietary assessments will be conducted at baseline and at the end of the intervention.
Intervention: Decreased Salt High Potassium Tool (DSHP Tool) (Behavioral)
Standard Care + DSHP Patient Information Leaflet
Participants in this arm will receive standard hypertension care as provided at SingHealth Polyclinics, along with the DSHP Patient Information Leaflet (PIL). The PIL provides written guidance on reducing sodium and increasing potassium intake. No access to the DSHP Tool will be provided in this arm. Participants will undergo the same clinical and dietary assessments as the intervention group at baseline and after 24 weeks.
Outcomes
Primary Outcomes
24 hour Urinary Sodium level
Time Frame: At baseline and at the end of the intervention (24 weeks)
24 hour urinary sodium level will be assessed at baseline and at the end of the intervention
24 hour urinary potassium level
Time Frame: at baseline and at the end of intervention (24 weeks)
24 hour urinary potassium level will be measured at baseline and at the end of intervention (24 weeks)
Secondary Outcomes
- Blood pressure(at baseline and at the end of intervention (24 weeks))
- Body mass index(at baseline and at the end of 24 weeks)
- Salt literacy scale(At baseline and at the end of intervention (24 weeks))
- DASH score(at baseline and at the end of intervention (24 weeks))
Investigators
Sun Jingfeng
Family Physician
SingHealth Polyclinics