China Salt Substitute Study in Tibet (CSSS-Tibet)

July 27, 2016 updated by: The George Institute for Global Health, China

China Salt Substitute Study in Tibet: Efficacy of Salt Substitute in Reducing Blood Pressure in Hypertensive Adults

The study was a single-blind randomized controlled trial conducted between February and August 2009 in two townships (Yangbajing and Gongtang) of Dangxiong County, an area at 4300 meters altitude in Tibet. A brief baseline survey and assessment for eligibility was performed before randomization. A total of 282 residents with known hypertension (systolic blood pressure ≥ 140mmHg) were recruited and randomly assigned to intervention or control with stratification by gender and baseline blood pressure. The intervention group received 6-month's supply of salt substitute (68% sodium chloride, 22% potassium chloride and 10% magnesium sulfate heptahydrate) and the control group 6-month's supply of regular salt (100% sodium chloride). After 3-month's intervention, the ones with a blood pressure above 140 mmHg / 90 mmHg will be given low-dose diuretic for further anti-hypertensive therapy. The study hypothesis is that salt-substitute will greatly reduce blood pressure in treated patients when compared to controls. Blood pressure levels were measured at baseline and followed up by trained observers using an automated sphygmomanometer and brief survey on level of compliance, amount of salt consumed, and reasons for non-compliance.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Hypertension is one of the most important risk factors that induce cardiovascular and cerebrovascular disease. Reducing the blood pressure levels of population can not only control the incidence of cardiovascular and cerebrovascular disease effectively, but also reduce the mortality. Anti-hypertension drug therapy has been proven to be an effective method to reduce blood pressure. Dietary sodium restriction and potassium supplementation is the core of dietary approaches to stop hypertension. Tibet is located on the Tibetan Plateau with an average altitude about 4000 meters above sea level. Tibetan diet is rich in meat but poor in vegetables and fruits. Salt intake is quite high due to habitual drinking of salty butter tea. Former national surveys showed a high prevalence of hypertension in Tibet. The investigators conducted this randomized controlled intervention study to test whether the investigators can offer a cost effective way to lower blood pressure and control hypertension in a sample of subjects from Yangbajing and Gongtang in Dangxiong County, Lhasa, Tibet.

A randomized controlled trial was conducted in Yangbajing Township and Gongtang Village in the Dangxiong county , Tibet. A total of 282 hypertensive patients were chosen as study subjects. The regular salt or salt substitution were randomly allocated to the two groups. The whole intervention last for 6 months, with Phase 1 for three months and a following Phase 2 for another three months. For Phase 1, the study subjects were allocated the regular salt or the salt substitute after a randomization. For Phase 2, the study subjects continued the intervention of regular salt or salt substitute while the ones with a blood pressure above 140mmHg/90 mmHg will be given low-dose diuretic for further anti-hypertensive therapy. During the whole intervention period, the study subjects were not informed of what kind of salt they were taking. Blood pressure was the major outcome and would be measured at baseline, 3 months and 6 months.

Study Type

Interventional

Enrollment (Actual)

282

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • China
    • Tibet
      • Lhasa, Tibet, China, 850000
        • Dangxiong People's Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

40 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Age 40 years or older
  • Resident of Yangbajing Township and Gongtang Village in Tibetan Autonomous Region, People's Republic of China
  • Mean Systolic Hypertension (≥ 140 mmHg)

Exclusion Criteria:

  • Currently taking any potassium supplements (or lives in household where someone does)
  • Previously diagnosed kidney disease or gout (or lives in a household where someone does) and physician considered he/she cannot take salt substitute.
  • Any person who intended to use salt outside the assigned treatment salt provide in the study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Normal Salt
100% Sodium Chloride
Dietary supplement: Regular Salt
Estimated Household Individual Consumption of 30 grams per day
Experimental: Salt Substitute
65% Sodium Chloride, 25% Potassium Chloride, 10% Magnesium Sulphate)
Dietary supplement: Salt Substitute
Estimated 30 grams per day per household member

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Baseline Mean Systolic Blood Pressure (mmHg) at 6 months
Time Frame: (Baseline compared to 6 months after start of intervention)
3 Serial in Right Arm with Seated Patients with at least 1 minute between measurements using Omron 751 Automated Cuff.
(Baseline compared to 6 months after start of intervention)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Percent of patients having blood pressure under control (<140/90 mmHg)
Time Frame: Baseline, and post start of intervention at 3 months and 6 months
Baseline, and post start of intervention at 3 months and 6 months
Change in Baseline Mean Systolic Blood Pressure (mmHg) at 3 months.
Time Frame: (Baseline compared to 3 months after start of intervention)
3 Serial in Right Arm with Seated Patients with at least 1 minute between measurements using Omron 751 Automated Cuff
(Baseline compared to 3 months after start of intervention)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

The George Institute for Global Health, China

Collaborators

Peking University
Beijing Jishuitan Hospital
People's Hospital of Dangxiong County

Investigators

  • Study Director: Yangfeng Wu, PhD, The George Institute, China (Beijing, CN)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

February 1, 2009

Primary Completion (Actual)

August 1, 2009

Study Completion (Actual)

August 1, 2009

Study Registration Dates

First Submitted

August 31, 2011

First Submitted That Met QC Criteria

September 2, 2011

First Posted (Estimate)

September 7, 2011

Study Record Updates

Last Update Posted (Estimate)

July 29, 2016

Last Update Submitted That Met QC Criteria

July 27, 2016

Last Verified

September 1, 2011

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • HHSN268200900027C (Other Grant/Funding Number: NHLBI)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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