China Salt Substitute Study in Tibet (CSSS-Tibet)

This study has been completed.
Sponsor:
Collaborators:
Peking University
Beijing Jishuitan Hospital
Dangxiong People's Hospital
Information provided by (Responsible Party):
The George Institute for Global Health, China
ClinicalTrials.gov Identifier:
NCT01429246
First received: August 31, 2011
Last updated: September 2, 2011
Last verified: September 2011
  Purpose

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.


Condition Intervention
Hypertension
Dietary Supplement: Regular Salt
Dietary Supplement: Salt Substitute

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Single Blind (Subject)
Primary Purpose: Treatment
Official Title: China Salt Substitute Study in Tibet: Efficacy of Salt Substitute in Reducing Blood Pressure in Hypertensive Adults

Resource links provided by NLM:


Further study details as provided by The George Institute for Global Health, China:

Primary Outcome Measures:
  • Change in Baseline Mean Systolic Blood Pressure (mmHg) at 6 months [ Time Frame: (Baseline compared to 6 months after start of intervention) ] [ Designated as safety issue: No ]
    3 Serial in Right Arm with Seated Patients with at least 1 minute between measurements using Omron 751 Automated Cuff.


Secondary Outcome Measures:
  • 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 ] [ Designated as safety issue: No ]
  • Change in Baseline Mean Systolic Blood Pressure (mmHg) at 3 months. [ Time Frame: (Baseline compared to 3 months after start of intervention) ] [ Designated as safety issue: No ]
    3 Serial in Right Arm with Seated Patients with at least 1 minute between measurements using Omron 751 Automated Cuff


Enrollment: 282
Study Start Date: February 2009
Study Completion Date: August 2009
Primary Completion Date: August 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
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

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.

  Eligibility

Ages Eligible for Study:   40 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

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
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01429246

Locations
China, Tibetan Autonomous Region
Dangxiong People's Hospital
Lhasa, Tibetan Autonomous Region, China, 850000
Sponsors and Collaborators
The George Institute for Global Health, China
Peking University
Beijing Jishuitan Hospital
Dangxiong People's Hospital
Investigators
Study Director: Yangfeng Wu, PhD The George Institute, China (Beijing, CN)
  More Information

Publications:

Responsible Party: The George Institute for Global Health, China
ClinicalTrials.gov Identifier: NCT01429246     History of Changes
Other Study ID Numbers: HHSN268200900027C
Study First Received: August 31, 2011
Last Updated: September 2, 2011
Health Authority: China: Bureau of Science and Technology of Tibet Autonomous Region

Keywords provided by The George Institute for Global Health, China:
Hypertension
Diet Therapy
Sodium Chloride, Dietary
Tibet
Aged

Additional relevant MeSH terms:
Hypertension
Vascular Diseases
Cardiovascular Diseases

ClinicalTrials.gov processed this record on August 21, 2014