Using a low-sodium, high-potassium salt substitute to reduce blood pressure among Tibetans with high blood pressure: a patient-blinded randomized controlled trial

Xingshan Zhao, Xuejun Yin, Xian Li, Lijing L Yan, Christopher T Lam, Shenshen Li, Feng He, Wuxiang Xie, Ba Sang, Gesang Luobu, Liang Ke, Yangfeng Wu, Xingshan Zhao, Xuejun Yin, Xian Li, Lijing L Yan, Christopher T Lam, Shenshen Li, Feng He, Wuxiang Xie, Ba Sang, Gesang Luobu, Liang Ke, Yangfeng Wu

Abstract

Objectives: To evaluate the effects of a low-sodium and high-potassium salt-substitute on lowering blood pressure (BP) among Tibetans living at high altitude (4300 meters).

Method: The study was a patient-blinded randomized controlled trial conducted between February and May 2009 in Dangxiong County, Tibetan Autonomous Region, China. A total of 282 Tibetans aged 40 or older with known hypertension (systolic BP≥140 mmHg) were recruited and randomized to intervention (salt-substitute, 65% sodium chloride, 25% potassium chloride and 10% magnesium sulfate) or control (100% sodium chloride) in a 1: 1 allocation ratio with three months' supply. Primary outcome was defined as the change in BP levels measured from baseline to followed-up with an automated sphygmomanometer. Per protocol (PP) and intention to treat (ITT) analyses were conducted.

Results: After the three months' intervention period, the net reduction in SBP/DBP in the intervention group in comparison to the control group was -8.2/-3.4 mmHg (all p<0.05) in PP analysis, after adjusting for baseline BP and other variables. ITT analysis showed the net reduction in SBP/DBP at -7.6/-3.5 mmHg with multiple imputations (all p<0.05). Furthermore, the whole distribution of blood pressure showed an overall decline in SBP/DBP and the proportion of patients with BP under control (SBP/DBP<140 mmHg) was significantly higher in salt-substitute group in comparison to the regular salt group (19.2% vs. 8.8%, p = 0.027).

Conclusion: Low sodium high potassium salt-substitute is effective in lowering both systolic and diastolic blood pressure and offers a simple, low-cost approach for hypertension control among Tibetans in China.

Trial registration: ClinicalTrials.gov NCT01429246.

Conflict of interest statement

Competing Interests: Part of study funding came from United Health Group. There is no competing interests there and the funding does not alter the authors' adherence to PLOS ONE policies on sharing data and materials.

Figures

Figure 1. Trial Flow Chart.
Figure 1. Trial Flow Chart.
Figure 2. Unadjusted mean change of blood…
Figure 2. Unadjusted mean change of blood pressure levels at the 3-month follow-up from baseline for the salt substitute group and regular salt group in ITT and PP analysis.
a: Intent-to-treat with multiple imputations approach, N = 282. b: Per-protocol analysis, N = 213.
Figure 3. Distribution of Blood pressure at…
Figure 3. Distribution of Blood pressure at baseline and follow-up, per-protocol analysis.

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Source: PubMed

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