Our results strongly suggest that any policy intervention achieving even a 1% population-wide reduction in risk of cardiovascular disease can be expected to produce a net cost saving to the NHS, as well as decreasing losses in productivity and improving health. Only if a very large sum of money needs to be spent on implementing the legislation would this cease to be the case. Our findings are reassuringly consistent with analyses from the United States, Australia, and the UK Treasury.7 8 9 10 11 12 13 14 15 26
Likewise, a five year campaign on salt reduction by the UK Food Standards Agency cost approximately £15m and achieved a reduction of 0.9 g/day in average salt intake. This was estimated to prevent approximately 6000 cardiovascular deaths a year, with estimated savings totalling some £1.5bn, or £300m a year.6
Furthermore, analyses of cohorts with lower cardiovascular risk show fewer cardiovascular events delayed to an older age and incurring substantially lower Medicare costs.27
The 5% reductions modelled for systolic blood pressure and cholesterol concentration are entirely consistent with the actual falls achieved in regional programmes such as North Karelia, Stanford, and HeartBeat Wales.28 29
Furthermore, much larger reductions in entire populations have been documented since the 1980s. For instance, cholesterol reductions of 22% in Finland, 14% in Iceland, 10% in Sweden, and 6% in the United States have been reported.30 31 32 33
Likewise, blood pressure reductions of 8% in England and 6% in Finland have been reported.29 30
Our 0.5% reduction in industrial trans
fats represents a conservative estimate of what is possible, given past UK trends and recent Danish experience of successful eradication.34
fats have now been banned in five European countries: Denmark, Switzerland, Austria, Sweden, and Iceland. Manufacturers have adapted rapidly, easily, and with minimal costs.35
We would suggest that the UK is unlikely to be very different. Furthermore, important inequalities exist, given the very high consumption of trans
fats recently reported in some disadvantaged groups (exceeding 6% of daily energy).35
Benefits in deprived communities might therefore be even larger.
Strengths of analysis
Our spreadsheet model allows a relative risk to be applied to each year’s risk of primary cardiovascular disease in the population. It also allows percentage reductions in cholesterol concentration and systolic blood pressure to be considered separately for men and women. The model is designed to be transparent and involves relatively few assumptions, each of which can be easily tested. Furthermore, the estimates are based on a series of conservative assumptions, so the true benefits are likely to be substantially larger.
We quantified only NHS savings. Net social savings will clearly be much larger. The model focuses on primary prevention of cardiovascular disease. All population-wide risk factor reduction programmes considered in this report would also benefit the five million patients with recognised cardiovascular disease in the UK.36 37
Substantial reductions in diabetes, many common cancers, and other chronic diseases would also occur.37
This simple model assumed a uniform distribution of burden and benefit across social groups. In fact, deprived groups have disproportionately more disease and would thus gain more from population-wide risk factor reductions. Absolute inequalities would also be decreased.38
This is not simply a cost of illness study. It is a modelling study that shows the range of possible cost savings and QALY benefits from a range of plausible interventions. It therefore allows an upper limit to be placed on the cost at which any such intervention would be worthwhile. Greater complexity in the model might lead to additional precision in the results. However, we suggest that this additional precision might make surprisingly little difference to the key policy decisions.
The sensitivity analyses were reassuring and suggested that using a different risk “engine” to drive the model would have a relatively modest effect. The model is based on the original Framingham equations and the same risk score as the Joint British Societies’ guidelines, which is widely used and understood. It also reflects the model that was presented to the NICE Programme Development Group to assist in their deliberations and inform their subsequent key recommendations.35
Limitations of analysis
Our conclusions are clearly subject to several important limitations reflecting the nature of the model. Apart from the increased mortality immediately after a first non-fatal primary cardiovascular event, we made no attempt to consider recurrent events or subsequent deaths. The estimates of deaths avoided, life years gained, and cost savings are thus likely to be underestimates, making the analysis somewhat conservative. A further limitation is the 10 year time frame for prevention of cases; gains over a lifetime would clearly be greater.
The analysis was pragmatically limited to people aged between 40 and 79 years at the time of the intervention. However, given the very high rates of cardiovascular events in people aged over 80, substantial additional benefits might be expected. Our interventions assumed relatively uniform effects across age and risk groups by definition. However, the subsequent changes in specific risk factors included age gradients and considered men and women separately.
In this study, the counterfactual (no intervention) implicitly assumes that the population risk of cardiovascular disease would remain constant. However, there may be a “natural” increase or decrease in cardiovascular risk without population-wide interventions. Modest changes could also follow targeted interventions in subgroups. Either of these scenarios might affect future costs and QALYs.
Finally, this initial modelling lacks a full probabilistic sensitivity analysis, because many essential data inputs (such as the distribution of risk factors in the population) were readily available only as point estimates. However, the range of changes in risk factors and their effects quantified in the results tables and web appendices provide a satisfactory and rigorous sensitivity analysis. Future studies might usefully include a full probabilistic sensitivity analysis to formally test the uncertainties inherent in the various modelling assumptions.
Implications of findings
We estimated that a 1% reduction in the relative risk of cardiovascular disease would generate discounted NHS savings of approximately £30m a year in England and Wales, compared with no additional intervention, This estimate is considerably less than 1% of the £7bn healthcare costs calculated by Luengo-Fernández et al.2
However, this again highlights the conservative approach taken in our modelling.
In terms of opportunity cost, any programme that reduces the rate of death from cardiovascular disease by 1% is cost effective up to costs of £30m, as long as no alternative programme causes a bigger reduction at the same costs or the same reduction at lower costs. Varying the underlying Framingham risk equation to include newer values such as QRISK2
will also be useful.39
However, the resulting changes are likely to be small. Furthermore, subsequent research should ensure that such models remain up to date, accessible, and credible. A better quantification of our understanding of causal pathways for cardiovascular disease will be challenging but important.
An important factor is the feasibility of population-wide dietary changes—for instance, in salt consumption. Cultural aspects are important in some countries, such as salted fish in Portugal and salted vodka further east. However, most populations now live in a global economy. We eat what is available, affordable, and acceptable. In our UK study population, that means that more than 80% of consumed salt is concealed in processed food.22 35
In the UK, media campaigns and voluntary agreements with the food industry have already achieved a 1 g reduction in salt consumption. We therefore suggest that a 3 g reduction might be entirely feasible by using more muscular regulatory approaches. The 6 g reductions in Finland and Japan were achieved in spite of cultural traditions and resistance from the industry.22 29
Furthermore, reductions of 5-10% in the salt content of any specific food during one year are simply not noticed by most consumers. This is because human taste buds adapt very quickly. Salt has already been substantially decreased in the UK and several other countries, with no evidence of widespread compensation by consumers.35
This paper does not detail the specific costs of particular programmes. It is making a more general argument. Given the benefits in terms of increased health and reduced healthcare costs, the sorts of programmes we have seen work in other countries must surely also be cost effective here.
Our model is relatively simple and transparent with clear limitations. However, the cumulative conservative assumptions mean that the benefits and cost savings are almost certainly underestimated. The findings are reassuringly consistent with results from very different methods in the United States, Australia, and the UK Treasury.7 8 9 26 27 40
Population-wide prevention interventions seem to be both powerful and cost saving.
What is already known on this topic
- Population-wide prevention programmes, such as salt reduction, trans fat eradication, or smoke-free legislation seem to be very effective for preventing cardiovascular disease
- Studies in the United States and Australia suggest that as well as reducing cardiovascular events and deaths, such programmes may also be cost saving
What this study adds
- A national programme reducing population cardiovascular risk by 1% would prevent approximately 25000 cardiovascular disease cases and generate public sector savings of about £30m a year
- Reducing mean population cholesterol or blood pressure levels by 5% (as already achieved in some other countries) would result in annual savings of approximately £80m or £100m
- Legislation or other measures to reduce dietary salt intake by 3 g/day or industrial trans fatty acid intake by approximately 0.7% of total energy content would save about £40m or £230m a year