Protocol for the economic evaluation of the China Salt Substitute and Stroke Study (SSaSS)

Q: What is the clinical evidence from this study?

Study design: RCT. Population: High risk of stroke (history of stroke or uncontrolled hypertension) (n=20996). Intervention: Sodium-reduced, potassium-enriched salt substitute vs. Regular salt with baseline advice on stroke prevention and salt reduction. Primary outcome: Incremental cost-effectiveness ratio (cost per cardiovascular event averted and cost per QALY gained).

Q: What does this research mean for the field?

Sodium-reduced, potassium-enriched salt substitution can be evaluated for cost-effectiveness per cardiovascular event averted and QALY gained within a large cluster-randomized trial in rural China. Novelty: ClaimNovelty.METHODOLOGICAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

Ka Chun Li; Maoyi Tian; Bruce Neal; Liping Huang; Jie Yu; Yishu Liu; Xuejun Yin; Xinyi Zhang; Yangfeng Wu; Nicole Li; Paul Elliott; Lijing L. Yan; Darwin R. Labarthe; Zhixin Hao; Xiangxian Feng; Jianxin Zhang; Yuhong Zhang; Ruijuan Zhang; Bo Zhou; Zhifang Li; Jixin Sun; Yi Zhao; Yan Yu; Lei Si; Thomas Lung

doi:10.1136/bmjopen-2020-045929

Why the study?

Prior economic evidence focused on sodium reduction in the food industry or processed foods with blood pressure as the outcome, leaving the cost-effectiveness of a low-sodium salt substitute to reduce stroke unstudied.

Is a sodium-reduced, potassium-enriched salt substitute a cost-effective intervention for preventing stroke, major cardiovascular events, and mortality compared with regular salt in a high-risk rural Chinese population?

Key Points

To describe the design of an economic evaluation assessing whether a low-sodium, potassium-enriched salt substitute is cost-effective for preventing stroke and major cardiovascular events in high-risk individuals.
Economic evaluation conducted alongside a 5-year, open-label, cluster randomized controlled trial across 600 villages in five Chinese provinces (N=20,996).
Clusters were randomized 1:1 to receive either free low-sodium salt substitute for all home cooking or to continue using regular salt.
Analyses adopt a healthcare system perspective, combining routine New Rural Cooperative Medical Scheme insurance data with health-related quality of life measured via the EQ-5D-5L.
Cost-effectiveness will be evaluated as the incremental cost-effectiveness ratio expressed as cost per major cardiovascular event and stroke averted.
Cost-utility will be assessed as cost per quality-adjusted life year gained, using EQ-5D-5L value sets developed for the Chinese population.
Medical care costs and adjudicated cardiovascular events will be captured via longitudinal health insurance databases and mortality surveillance records.

Study Design

Type

RCT (n=20,996)

Randomization

Cluster randomization, stratified at the county level with 1:1 allocation of villages

Multicenter

Yes

Structured PICO

Is a sodium-reduced, potassium-enriched salt substitute a cost-effective intervention for preventing stroke, major cardiovascular events, and mortality compared with regular salt in a high-risk rural Chinese population?

P

Population

20,996 rural Chinese adults across 600 villages at high risk of stroke (prior stroke or age >=60 with uncontrolled hypertension), followed for 5 years.

I

Intervention

Sodium-reduced, potassium-enriched salt substitute provided free of charge to replace all regular salt used in home cooking for the whole family over 5 years, accompanied by oral, written, and promotional reminders (e.g., cooking apron) to minimize total usage.

C

Comparator

Continued use of regular salt, with advice about stroke prevention and salt reduction provided only at trial commencement.

O

Outcome

Incremental cost-effectiveness ratio (ICER) expressed as cost per cardiovascular event (stroke and other major adverse cardiac events, adjudicated by an independent committee) averted and cost per quality-adjusted life year (QALY, measured via EQ-5D-5L) gained over the 5-year trial period from a healthcare system perspective.hard clinical

This protocol outlines the first within-trial economic evaluation assessing the cost-effectiveness of dietary salt substitution on hard cardiovascular morbidity and mortality outcomes rather than blood pressure alone.

Limitations

Adherence to salt substitute observed in the trial (provided free of charge) may not reflect real-world compliance.
New Rural Cooperative Medical Scheme (NCMS) does not reach 100% coverage and participants may drop out from the NCMS.
Most quality of life (EQ-5D-5L) data were collected from a random subset (10% of clusters) during the four mid-term follow-ups, requiring imputation for missing values.
Adherence and increased compliance in using salt substitute observed in the trial may not reflect real-world settings.
The New Rural Cooperative Medical Scheme (NCMS) does not reach 100% coverage and participants may drop out.
Most quality of life data were collected from a random subset (10% of clusters) of the trial population during the four mid-term follow-ups, requiring imputation.

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Implication

This planned RCT economic evaluation will determine salt substitution cost-effectiveness per event and QALY; delivers first direct evidence on hard cardiovascular outcomes.

Abstract

INTRODUCTION: Cardiovascular diseases (CVDs) are the leading causes of death and disability worldwide. Reducing dietary salt consumption is a potentially cost-effective way to reduce blood pressure and the burden of CVD. To date, economic evidence has focused on sodium reduction in food industry or processed food with blood pressure as the primary outcome. This study protocol describes the planned within-trial economic evaluation of a low-sodium salt substitute intervention designed to reduce the risk of stroke in China. METHODS AND ANALYSES: The economic evaluation will be conducted alongside the Salt Substitute and Stroke Study: a 5-year large scale, cluster randomised controlled trial. The outcomes of interest are quality of life measured using the EuroQol-5-Dimensions and major adverse cardiovascular events. Costs will be estimated from a healthcare system perspective and will be sought from the routinely collected data available within the New Rural Cooperative Medical Scheme. Cost-effectiveness and cost-utility analyses will be conducted, resulting in the incremental cost-effectiveness ratio expressed as cost per cardiovascular event averted and cost per quality-adjusted life year gained, respectively. ETHICS AND DISSEMINATION: The trial received ethics approval from the University of Sydney Ethics Committee (2013/888) and Peking University Institutional Review Board (IRB00001052-13069). Informed consent was obtained from each study participant. Findings of the economic evaluation will be published in a peer-reviewed journal and presented at international conferences. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT02092090).

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Cite This Study

Li et al. (2021) conducted an RCT in High risk of stroke (history of stroke or uncontrolled hypertension) (n=20,996). Sodium-reduced, potassium-enriched salt substitute vs. Regular salt with baseline advice on stroke prevention and salt reduction was evaluated on Incremental cost-effectiveness ratio (cost per cardiovascular event averted and cost per QALY gained).

synapsesocial.com/papers/6a819648a19bfff313b95624 https://doi.org/10.1136/bmjopen-2020-045929

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Protocol for the economic evaluation of the China Salt Substitute and Stroke Study (SSaSS)

Key Points

Study Design

Structured PICO

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

Protocol for the economic evaluation of the China Salt Substitute and Stroke Study (SSaSS)

Key Points

Study Design

Structured PICO

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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