Dietary Salt Reduction, Prevalence of Hypertension and Avoidable Burden of Stroke in Vietnam: Modelling the Health and Economic Impacts

Comprehensive analysis of stroke epidemiology in Vietnam: Insights from GBD 1990-2019 and RES-Q 2017-2023

Background

Stroke is a significant health burden in Vietnam, with substantial impacts on mortality, morbidity, and healthcare resources. An up-to-date report on stroke epidemiology and associated risk factors in Vietnam was missing.

Method

We analyzed the data published in the Global Burden of Disease (GBD) 2019, in combination with the first-time analysis of the Registry of Stroke Care Quality Improvement (RES-Q) initiative in Vietnam from 2017 to 2023.

Findings

Comparative analysis globally revealed that Vietnam had one of the highest stroke incidence and prevalence rates in Southeast Asia and ranked 4th in stroke mortality among 11 neighbouring countries. In the RES-Q dataset, 95,696 patients (77 %) were ischemic stroke, 23,203 (18 %) were intracerebral haemorrhage, and 2816 (2 %) were subarachnoid haemorrhage. In GBD 2019, stroke was the leading cause of death among cardiovascular diseases in Vietnam, accounting for 135,999 fatalities. The incidence of stroke was 222 (95 % UIs 206-242) per 100,000 population, with a prevalence of 1541 (1430-1679) per 100,000. Results align with the report from the RES-Q dataset in two megacities of Vietnam: Hanoi (incidence rate of 168.9, prevalence rate of 1182.2) and Ho Chi Minh City (incidence rate of 207.1, prevalence rate of 1221.8). Key risk factors for stroke mortality are high systolic blood pressure (79,000 deaths), unhealthy dietary (43,000 deaths), high fasting plasma glucose (35,000 deaths), and air pollution (33,000 deaths). Incidence is lower in rural Vietnam, but availability and quality of care are higher in megacities.

Interpretation

The results promote a further understanding of stroke and risk factors for the Vietnamese population and suggest prevention and treatment strategies for the Vietnamese government, including facility and capacity improvement and applications of advanced technologies.

Public health economic modelling in evaluations of salt and/or alcohol policies: a systematic scoping review

BACKGROUND

Public health economic modelling is an approach capable of managing the intricacies involved in evaluating interventions without direct observational evidence. It is used to estimate potential long-term health benefits and cost outcomes. The aim of this review was to determine the scope of health economic models in the evaluation of salt and/or alcohol interventions globally, to provide an overview of the literature and the modelling methods and structures used.

METHODS

Searches were conducted in Medline, Embase, and EconLit, and complemented with citation searching of key reviews. The searches were conducted between 13/11/2022 and 8/11/2023, with no limits to publication date. We applied a health economic search filter to select model-based economic evaluations of public health policies and interventions related to alcohol consumption, dietary salt intake, or both. Data on the study characteristics, modelling approaches, and the interventions were extracted and synthesised.

RESULTS

The search identified 1,958 articles, 82 of which were included. These included comparative risk assessments (29%), multistate lifetables (27%), Markov cohort (22%), microsimulation (13%), and other (9%) modelling methods. The included studies evaluated alcohol and/or salt interventions in a combined total of 64 countries. Policies from the UK (23%) and Australia (18%) were the most frequently evaluated. A total of 58% of the models evaluated salt policies, 38% evaluated alcohol policies, and only three (4% of included modelling studies) evaluated both alcohol- and salt-related policies. The range of diseases modelled covered diabetes and cardiovascular disease-related outcomes, cancers, and alcohol-attributable harm. Systolic blood pressure was a key intermediate risk factor in the excessive salt-to-disease modelling pathway for 40 (83%) of the salt modelling studies. The effects of alcohol consumption on adverse health effects were modelled directly using estimates of the relative risk of alcohol-attributable diseases.

CONCLUSIONS

This scoping review highlights the substantial utilisation of health economic modelling for estimating the health and economic impact of interventions targeting salt or alcohol consumption. The limited use of combined alcohol and salt policy models presents a pressing need for models that could explore their integrated risk factor pathways for cost-effectiveness comparisons between salt and alcohol policies to inform primary prevention policymaking.

Role of dietary potassium and salt substitution in the prevention and management of hypertension

Cardiovascular diseases (CVD) continue to be the leading cause of deaths and disability worldwide and the major contributor is hypertension. Despite all the improvements in detecting hypertension together with technological advances and affordable, efficacious and relatively free of adverse effects anti-hypertensive agents, we continue to struggle to prevent the onset of hypertension and to control blood pressure (BP) to acceptable targets. The poor control of hypertension is commonly due to non-adherence to medications. Another reason is the failure to adopt diet and lifestyle changes. Reduction of dietary salt intake is important for lowering BP but the role of potassium intake is also important. Globally the intake of sodium is double that of the recommended 2 gm per day (equivalent to 5 gm of sodium chloride/salt) and half that of the daily recommended intake of potassium of 3500 mg/day, giving a sodium-to-potassium ratio of >1, when ideally it should be <1. Many studies have shown that a higher potassium intake is associated with lower BPs, particularly when coupled concurrently with a lower sodium intake giving a lower sodium to potassium ratio. Most hypertension guidelines, while recommending reduction of salt intake to a set target, do not specifically recommend a target for potassium intake nor potassium supplementation. Here we review the role of potassium and salt substitution with potassium in the management of hypertension. Hence, the focus of dietary changes to lower BP and improve BP control should not be on reduction of salt intake alone but more importantly should include an increase in potassium intake.

Comparative Prevalence of Cerebrovascular Disease in Vietnamese Communities in South-Western Sydney

Culturally and linguistically diverse (CALD) communities are growing globally. Understanding patterns of cerebrovascular disease in these communities may improve health outcomes. We aimed to compare the rates of transient ischaemic attack (TIA), ischaemic stroke (IS), intracerebral haemorrhage (ICH), intracranial atherosclerosis (ICAD), and stroke risk factors in Vietnamese-born residents of South-Western Sydney (SWS) with those of an Australian-born cohort. A 10-year retrospective analysis (2011-2020) was performed using data extracted from the Health Information Exchange database characterising stroke presentations and risk factor profiles. The rates of hypertension (83.7% vs. 70.3%, p < 0.001) and dyslipidaemia (81.0% vs. 68.2%, p < 0.001) were significantly higher in Vietnamese patients, while the rates of ischaemic heart disease (10.4% vs. 20.3%, p < 0.001), smoking (24.4% vs. 40.8%, p < 0.001), and alcohol abuse (>1 drink/day) (9.6% vs. 15.9%, p < 0.001) were lower. The rates of ICAD and ICH were higher in Vietnamese patients (30.9% vs. 6.9%, p < 0.001 and 24.7% vs. 14.4%, p = 0.002). Regression analysis revealed that diabetes (OR: 1.86; 95% CI: 1.14-3.04, p = 0.014) and glycosylated haemoglobin (OR: 1.51; 95% CI: 1.15-1.98, p = 0.003) were predictors of ICAD in Vietnamese patients. Vietnamese patients had higher rates of symptomatic ICAD and ICH, with unique risk factor profiles. Culturally specific interventions arising from these findings may more effectively reduce the community burden of disease.

Economic effects of dietary salt reduction policies for cardiovascular disease prevention in Japan: a simulation study of hypothetical scenarios

Objective

Reducing dietary salt intake is an essential population strategy for cardiovascular disease (CVD) prevention, but evidence on healthcare costs and outcomes is limited in Japan. We aimed to conduct a pilot economic evaluation under hypothetical scenarios of applying the salt reduction policies of England to Japan.

Methods

We examined salt reduction policies in England: media health promotion campaigns, front-of-pack labeling, and voluntary and mandatory reformulation with best-case and worst-case policy cost scenarios. We assumed that these policies were conducted in Japan for 10 years from 2019. We used published data on epidemiology and healthcare expenditures in Japan and the costs and effects of salt reduction policies in England, and defined the benefits as a decrease in national medical expenditures on CVD. We developed a Markov cohort simulation model of the Japanese population. To estimate the annual net benefits of each policy over 10 years, we subtracted monitoring and policy costs from the benefits. We adopted a health sector perspective and a 2% discount rate.

Results

The cumulative net benefit over 10 years was largest for mandatory reformulation (best case) at 2,015.1 million USD (with costs of USD 48.3 million and benefits of USD 2063.5 million), followed by voluntary reformulation (net benefit: USD 1,895.1 million, cost: USD 48.1 million, benefit: USD 1,943.2 million), mandatory reformulation (worst case, net benefit: USD 1,447.9 million, cost: USD 1,174.5 million, benefit: USD 2,622.3 million), labeling (net benefit: USD 159.5 million, cost: USD 91.6 million, benefit: USD 251.0 million), and a media campaign (net benefit: USD 140.5 million, cost: USD 110.5 million, benefit: USD 251.0 million). There was no change in the superiority or inferiority of policies when the uncertainty of model parameters was considered.

Conclusion

Mandatory reformulation with the best-case cost scenario might be economically preferable to the other alternatives in Japan. In future research, domestic data on costs and effects of salt reduction policies should be incorporated for model refinement.

Cost-effectiveness of non-communicable disease prevention in Southeast Asia: a scoping review

Background

Cost-effectiveness analyses (CEAs) on prevention of non-communicable diseases (NCDs) are necessary to guide decision makers to allocate scarce healthcare resource, especially in Southeast Asia (SEA), where many low- and middle-income countries (LMICs) are in the process of scaling-up preventive interventions. This scoping review aims to summarize the cost-effectiveness evidence of primary, secondary, or tertiary prevention of type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVDs) as well as of major NCDs risk factors in SEA.

Methods

A scoping review was done following the PRISMA checklist for Scoping Reviews. Systematic searches were performed on Cochrane Library, EconLit, PubMed, and Web of Science to identify CEAs which focused on primary, secondary, or tertiary prevention of T2DM, CVDs and major NCDs risk factors with the focus on primary health-care facilities and clinics and conducted in SEA LMICs. Risks of bias of included studies was assessed using the Consensus of Health Economic Criteria list.

Results

This study included 42 CEAs. The interventions ranged from screening and targeting specific groups for T2DM and CVDs to smoking cessation programs, discouragement of smoking or unhealthy diet through taxation, or health education. Most CEAs were model-based and compared to a do-nothing scenario. In CEAs related to tobacco use prevention, the cost-effectiveness of tax increase was confirmed in all related CEAs. Unhealthy diet prevention, mass media campaigns, salt-reduction strategies, and tax increases on sugar-sweetened beverages were shown to be cost-effective in several settings. CVD prevention and treatment of hypertension were found to be the most cost-effective interventions. Regarding T2DM prevention, all assessed screening strategies were cost-effective or even cost-saving, and a few strategies to prevent T2DM complications were found to be cost-effective in certain settings.

Conclusion

This review shows that the cost-effectiveness of preventive strategies in SEA against T2DM, CVDs, and their major NCDs risk factors are heterogenous in both methodology as well as outcome. This review combined with the WHO "best buys" could guide LMICs in SEA in possible interventions to be considered for implementation and upscaling. However, updated and country-specific information is needed to further assess the prioritization of the different healthcare interventions.

Systematic review registration

https://osf.io, identifier: 10.17605/OSF.IO/NPEHT.

Avoidable burden of stomach cancer and potential gains in healthy life years from gradual reductions in salt consumption in Vietnam, 2019-2030: a modelling study

OBJECTIVE

Excess salt consumption is causally linked with stomach cancer, and salt intake among adults in Vietnam is about twice the recommended levels. The aim of this study was to quantify the future burden of stomach cancer that could be avoided from population-wide salt reduction in Vietnam.

DESIGN

A dynamic simulation model was developed to quantify the impacts of achieving the 2018 National Vietnam Health Program (8 g/d by 2025 and 7 g/d by 2030) and the WHO (5 g/d) salt reduction policy targets. Data on salt consumption were obtained from the Vietnam 2015 WHO STEPS survey. Health outcomes were estimated over 6-year (2019-2025), 11-year (2019-2030) and lifetime horizons. We conducted one-way and probabilistic sensitivity analyses.

SETTING

Vietnam.

PARTICIPANTS

All adults aged ≥ 25 years (61 million people, 48·4 % men) alive in 2019.

RESULTS

Achieving the 2025 and 2030 national salt targets could result in 3400 and 7200 fewer incident cases of stomach cancer, respectively, and avert 1900 and 4800 stomach cancer deaths, respectively. Achieving the WHO target by 2030 could prevent 8400 incident cases and 5900 deaths from stomach cancer. Over the lifespan, this translated to 344 660 (8 g/d), 411 060 (7 g/d) and 493 633 (5 g/d) health-adjusted life years gained, respectively.

CONCLUSIONS

A sizeable burden of stomach cancer could be avoided, with gains in healthy life years if national and WHO salt targets were attained. Our findings provide impetus for policy makers in Vietnam and Asia to intensify salt reduction strategies to combat stomach cancer and mitigate pressure on the health systems.

Estimated Impact of Achieving the Australian National Sodium Reduction Targets on Blood Pressure, Chronic Kidney Disease Burden and Healthcare Costs: A Modelling Study

Excess sodium intake raises blood pressure which increases the risk of chronic kidney disease (CKD). We aimed to estimate the impact of reduced sodium intake on future CKD burden in Australia. A multi-cohort proportional multistate lifetable model was developed to estimate the potential impact on CKD burden and health expenditure if the Australian Suggested Dietary Target (SDT) and the National Preventive Health Strategy 2021-2030 (NPHS) sodium target were achieved. Outcomes were projected to 2030 and over the lifetime of adults alive in 2019. Achieving the SDT and NPHS targets could lower population mean systolic blood pressure by 2.1 mmHg and 1.7 mmHg, respectively. Compared to normal routines, attaining the SDT and NPHS target by 2030 could prevent 59,220 (95% UI, 53,140-65,500) and 49,890 (44,377-55,569) incident CKD events, respectively, while postponing 568 (479-652) and 511 (426-590) CKD deaths, respectively. Over the lifetime, this generated 199,488 health-adjusted life years (HALYs) and AUD 644 million in CKD healthcare savings for the SDT and 170,425 HALYs and AUD 514 million for the NPHS. CKD due to hypertension and CKD due to other/unspecified causes were the principal contributors to the HALY gains. Lowering sodium consumption in Australia could deliver substantial CKD health and economic benefits.

Association Between DNA Methylation and Blood Pressure: A 5-Year Longitudinal Twin Study

BACKGROUND

Previous EWASs (Epigenome-Wide Association Studies) have reported hundreds of blood pressure (BP) associated 5'-cytosine-phosphate-guanine-3' (CpG) sites. However, their results were inconsistent. Longitudinal observations on the temporal relationship between DNA methylation and BP are lacking.

METHODS

A candidate CpG site association study for BP was conducted on 1072 twins in the Chinese National Twin Registry. PubMed and EMBASE were searched for candidate CpG sites. Cross-lagged models were used to assess the temporal relationship between BP and DNA methylation in 308 twins who completed 2 surveys in 2013 and 2018. Then, the significant cross-lagged associations were validated by adopting the Inference About Causation From Examination of Familial Confounding approach. Finally, to evaluate the cumulative effects of DNA methylation on the progression of hypertension, we established methylation risk scores based on BP-associated CpG sites and performed Markov multistate models.

RESULTS

16 and 20 CpG sites were validated to be associated with systolic BP and diastolic BP, respectively. In the cross-lagged analysis, we detected that methylation of 2 CpG sites could predict subsequent systolic BP, and systolic BP predicted methylation at another 3 CpG sites. For diastolic BP, methylation at 3 CpG sites had significant cross-lagged effects for predicting diastolic BP levels, while the prediction from the opposite direction was observed at one site. Among these, 3 associations were validated in the Inference About Causation From Examination of Familial Confounding analysis. Using the Markov multistate model, we observed that methylation risk scores were associated with the development of hypertension.

CONCLUSIONS

Our findings suggest the significance of DNA methylation in the development of hypertension.

Reduction of Cardiovascular Events and Related Healthcare Expenditures through Achieving Population-Level Targets of Dietary Salt Intake in Japan: A Simulation Model Based on the National Health and Nutrition Survey

Reducing population dietary salt intake is expected to help prevent cardiovascular disease and thus constrain increasing national healthcare expenditures in Japan’s super-aged society. We aimed to estimate the impact of achieving global and national salt-reduction targets (8, <6, and <5 grams/day) on cardiovascular events and national healthcare spending in Japan. Using published data including mean salt intake and systolic blood pressure from the 2019 National Health and Nutrition Survey, we developed a Markov model of a closed cohort of adults aged 40−79 years in 2019 (n = 66,955,000) transitioning among six health states based on the disease course of ischemic heart disease (IHD) and stroke. If mean salt intake were to remain at 2019 levels over 10 years, cumulative incident cases in the cohort would be approximately 2.0 million for IHD and 2.6 million for stroke, costing USD 61.6 billion for IHD and USD 104.6 billion for stroke. Compared with the status quo, reducing mean salt intake towards the targets over 10 years would avert 1−3% of IHD and stroke events and save up to 2% of related national healthcare costs. Attaining dietary salt-reduction goals among adults would yield moderate health economic benefits in Japan.