Launching a Salt Substitute to Reduce Blood Pressure at the Population Level in Peru

Study Overview
=================
Brief Summary
-----------------
This protocol aims to implement, using a stepped wedge trial design, a population-level intervention to replace high-sodium salt for a salt substitute (low-sodium, high-potassium salt) to reduce blood pressure levels among adults aged 18 years and over of the semi-urban area of Tumbes. We hypothesize that participants aged 18 years and over from villages receiving a salt substitute will have lower blood pressure compared to control villages.

Detailed Description
-----------------
Several randomized clinical trials and meta-analysis have reported that reduction of sodium intake decreases blood pressure. Also, the increase of potassium ingestion in minimal doses has been found in systematic reviews to produce a small reduction in blood pressure levels. The proposed intervention is a community-wide mass-strategy in which direct delivery of a salt substitute to households is accompanied by wide social marketing campaigns, both before and during the intervention period. With this experimental stepped wedge trial design, we will estimate the impact of a reduced-sodium salt substitution program on blood pressure at the population level. We propose the following specific aims: Specific Aim 1: To implement and assess the impact of an intervention using a salt substitute on blood pressure at the population level using a stepped wedge trial design. Specific Aim 2: To determine costs and efficacy of this implementation strategy using cost-effectiveness analysis.

Official Title
-----------------
Launching a Salt Substitute to Reduce Blood Pressure at the Population Level - Peru

Conditions
-----------------
Blood Pressure, Hypertension

Intervention / Treatment
-----------------
* Other: Salt substitute


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Males or females aged 18 years and over from the randomly selected villages. Capable of understanding study procedures and providing informed consent. Full-time resident in the area. Exclusion Criteria: Self-reported history of chronic kidney disease or heart disease. Refusal to participate.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Prevention
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Salt substitute<br>As described by Brown, in a stepped wedge design, an intervention is rolled-out sequentially to the trial participants (either as individuals or clusters of individuals) over a number of time periods. The order in which the different individuals or clusters receive the intervention is determined at random and, by the end of the random allocation, all individuals or groups will have received the intervention. Stepped wedge designs incorporate data collection at each point where a new group (step) receives the intervention. Thus, the salt substitute will be implemented in each cluster (village) in a randomized fashion. Not arms are needed since the 6 randomly-selected villages will be implemented in some moment of the protocol. | Other: Salt substitute<br>* A salt substitute using 25% of potassium chloride and 75% of sodium chloride will be implemented in each of the villages.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Systolic/diastolic blood pressure (mmHg) | We will assess changes in systolic and diastolic blood pressure over time. Periodic assessments will be carried out to obtain clinical measurements. Every five months, a new evaluation will be performed in all participant villages (intervention and control). Systolic and diastolic blood pressure will be measured in triplicate using standard procedures and automated and validated devices. These periodic assessments will be taken at each household to guarantee contact with each family member enrolled in this study. | Three years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Progression to hypertension | Using data of systolic and diastolic blood pressure, we will estimate progression towards hypertension among participants in intervened and control villages. | Three years | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Blood pressure, Hypertension, Stepped wedge trial design