Coronary heart disease (CHD) death rates have been falling across most of Europe in recent decades. However, CHD remains the leading cause of mortality. Furthermore, the burden of CHD may be increasing due to a variety of factors including reductions in case-fatality (resulting in more CHD survivors and increasing prevalence), population ageing, and globalisation. There are also worrying signs that favourable risk factor trends (declines in smoking, blood pressure, and blood cholesterol) may be stalling and that at least in some countries CHD mortality in younger age groups has not declined or has declined more slowly in recent years.

Data on regional trends and predictions are available but these may conceal important differences between populations. For all these reasons it is essential to assess the likely future trends in CHD mortality in a range of European populations. It is also important to quantify the potential impact of cost-effective, population wide policy interventions on future trends in the burden of disease. We performed these analyses using a well-known CHD model (IMPACT) which has been widely used to explain past trends in CHD mortality in many European countries.

The key objectives were therefore to:

• Identify data sources across a range of European countries and populate CHD IMPACT models with the available data up to at least the year 2020.
• Validate the CHD IMPACT model for forward projection by comparing the model predicted CHD mortality (based on recent trends in CHD risk factors in each country) with recent observed CHD mortality (government statistics).
• Estimate the future burden of CHD disease (mortality) in each country to at least the year 2020.
• Identify a series of realistic policy options for appraisal that could be modelled using the CHD IMPACT model, through discussion with stakeholders in each country.
• Explore the impact of implementing these policy scenarios up to 2020 and beyond using the newly developed and validated IMPACT model in each country.

Methods

1. We developed the previously validated retrospective CHD IMPACT models in nine European populations (Scotland, Republic of Ireland, Northern Ireland, Sweden, Finland, Iceland, Czech Republic, Poland, and Italy). In four regions we were able to explicitly validate the model for forward projection by comparing IMPACT model CHD mortality estimates with recently observed CHD mortality trends (Scotland, Northern Ireland, Republic of Ireland, and Sweden).
2. We then projected CHD mortality to 2020 and 2030 using national data on population estimates, CHD mortality, and major risk factor trends. Because future trends in CHD mortality are uncertain, we used two counterfactuals (alternative sets of assumptions), one representing the status quo (CHD mortality remaining constant since around the year 2010), and one using a negative exponential distribution to predict future mortality declines.
3. Through discussion with stakeholders we identified a series of policy options for appraisal (such as reductions in dietary salt and saturated fat intakes and reductions in physical inactivity and smoking).
4. Finally, we estimated the effects of possible policy interventions on CHD mortality in 2020 in each country, including drawing lessons about likely impact and generalisability.
5. For pragmatic reasons, medical treatment efficacy and uptake were kept constant in this analysis though in reality significant improvements may be expected by 2020.

Results

The IMPACT Model validation which took place in four countries demonstrated acceptable agreement between predicted future CHD mortality and observed mortality (varying from 80% to 106%). Stakeholders approached were reasonably consistent in prioritising population wide primary prevention interventions (particularly policies to alter dietary nutrient intake, increase physical activity, and reduce smoking). We then modelled feasible policy scenarios to reflect these priorities. The scenarios modelled were reductions in smoking [of 5%, 10% or 15%], and in saturated fat intake [of -1%, -2% or -3% total energy intake] and salt intake [-10%, -20% or -30%], plus increases in physical activity [+5%, +10% or +15%]. Predicting future trends clearly involves uncertainties. However, unless there are substantial improvements in CHD mortality, most countries will see a large increase in the CHD disease burden, mainly due to population ageing.

The most optimistic policy scenarios modelled could reduce CHD mortality substantially, by up to around one third in each country. Roughly 40% of this mortality reduction would be achieved by the proposed alterations in nutrient intakes, 40% from changes in smoking prevalence, and approximately 20% from improvements in physical activity. These results were relatively consistent across diverse populations, under different assumptions about future CHD mortality trends and applying probabilistic sensitivity analyses.

Conclusions

Small and eminently feasible population reductions in cardiovascular risk factors such as cigarette smoking, dietary salt, saturated fat and physical inactivity could substantially decrease future coronary heart disease deaths in Europe, thus consolidating the earlier gains. However, whilst not an original objective, our analyses identified some unfavourable risk factor trends in recent years in several countries (in blood pressure, cholesterol, obesity and diabetes). If these adverse trends continue, future prevention goals might become very challenging.

The full report can be downloaded via this link.