China Salt Substitute Study in Tibet (CSSS-Tibet)

Study Description

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Study Description Study Design Arms and Interventions Outcome Measures Eligibility Criteria Contacts and Locations More Information

Brief Summary:

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 or disease	Intervention/treatment	Phase
Hypertension	Dietary Supplement: Regular Salt; Dietary Supplement: Salt Substitute	Not Applicable

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 Design

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Study Type :	Interventional (Clinical Trial)
Actual Enrollment :	282 participants
Allocation:	Randomized
Intervention Model:	Parallel Assignment
Masking:	Single (Participant)
Primary Purpose:	Treatment
Official Title:	China Salt Substitute Study in Tibet: Efficacy of Salt Substitute in Reducing Blood Pressure in Hypertensive Adults
Study Start Date :	February 2009
Actual Primary Completion Date :	August 2009
Actual Study Completion Date :	August 2009

Arms and Interventions

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Study Description Study Design Arms and Interventions Outcome Measures Eligibility Criteria Contacts and Locations More Information

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

Outcome Measures

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Primary Outcome Measures :

1. 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.

Secondary Outcome Measures :

1. 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 ]
2. 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

Eligibility Criteria

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Study Description Study Design Arms and Interventions Outcome Measures Eligibility Criteria Contacts and Locations More Information

Ages Eligible for Study:	40 Years and older (Adult, Senior)
Sexes Eligible for Study:	All
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

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Study Description Study Design Arms and Interventions Outcome Measures Eligibility Criteria Contacts and Locations More Information

Locations

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

Sponsors and Collaborators

The George Institute for Global Health, China

Peking University

Beijing Jishuitan Hospital

People's Hospital of Dangxiong County

Investigators

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

More Information

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Publications:

Tian HG, Guo ZY, Hu G, Yu SJ, Sun W, Pietinen P, Nissinen A. Changes in sodium intake and blood pressure in a community-based intervention project in China. J Hum Hypertens. 1995 Dec;9(12):959-68.

Hooper L, Bartlett C, Davey SG, Ebrahim S. Advice to reduce dietary salt for prevention of cardiovascular disease. Cochrane Database Syst Rev. 2004;(1):CD003656. Review.

He FJ, MacGregor GA. Effect of longer-term modest salt reduction on blood pressure. Cochrane Database Syst Rev. 2004;(3):CD004937. Review. Update in: Cochrane Database Syst Rev. 2013;4:CD004937.

China Salt Substitute Study Collaborative Group. Salt substitution: a low-cost strategy for blood pressure control among rural Chinese. A randomized, controlled trial. J Hypertens. 2007 Oct;25(10):2011-8.

Zhou X, Liu JX, Shi R, Yang N, Song DL, Pang W, Li YM. Compound ion salt, a novel low-sodium salt substitute: from animal study to community-based population trial. Am J Hypertens. 2009 Sep;22(9):934-42. doi: 10.1038/ajh.2009.135. Epub 2009 Aug 6.

He FJ, MacGregor GA. Can a low-sodium, high-potassium salt substitute reduce blood pressure in rural Chinese people? Nat Clin Pract Cardiovasc Med. 2008 Apr;5(4):186-7. doi: 10.1038/ncpcardio1122. Epub 2008 Jan 29.

Hu J, Jiang X, Li N, Yu X, Perkovic V, Chen B, Zhao L, Neal B, Wu Y. Effects of salt substitute on pulse wave analysis among individuals at high cardiovascular risk in rural China: a randomized controlled trial. Hypertens Res. 2009 Apr;32(4):282-8. doi: 10.1038/hr.2009.7. Epub 2009 Feb 27.

Li N, Prescott J, Wu Y, Barzi F, Yu X, Zhao L, Neal B; China Salt Substitute Study Collaborative Group. The effects of a reduced-sodium, high-potassium salt substitute on food taste and acceptability in rural northern China. Br J Nutr. 2009 Apr;101(7):1088-93. doi: 10.1017/S0007114508042360. Epub 2008 Aug 19.

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):

Zhao X, Yin X, Li X, Yan LL, Lam CT, Li S, He F, Xie W, Sang B, Luobu G, Ke L, Wu Y. Using a low-sodium, high-potassium salt substitute to reduce blood pressure among Tibetans with high blood pressure: a patient-blinded randomized controlled trial. PLoS One. 2014 Oct 22;9(10):e110131. doi: 10.1371/journal.pone.0110131. eCollection 2014.

Responsible Party:	The George Institute for Global Health, China
ClinicalTrials.gov Identifier:	NCT01429246 History of Changes
Other Study ID Numbers:	HHSN268200900027C
First Posted:	September 7, 2011
Last Update Posted:	July 29, 2016
Last Verified:	September 2011

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