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Chapter 1: Coronary heart disease and stroke: Reducing amenable mortality

Introduction

Over the past 10 years Scotland has seen a steady fall in the mortality rates of the cardiovascular diseases ( CVD) of coronary heart disease ( CHD) and stroke. Figure 1 shows the progress made between 1995 and 2006 towards the 2010 target of a 60% reduction in CHD deaths in those aged less than 75.

Although Scotland remains on course to meet this target, it is a matter of concern that the rate of decline in CHD mortality for men and women aged 35-54 years shows recent significant levelling off. Specifically, the average annual percentage fall in the rate in men changed from 6% between 1986 and 2003 to a fall of 0.5% between 2003 and 2006. There was also a small increase in mortality rates in young men between 2005 and 2006. Recent evidence suggests that the risk of developing heart disease is increasing in younger men between the ages of 35 and 55. This adverse trend reflects what is happening in other parts of the world, including England, Wales and the USA. It is probable that unfavourable trends in cardiovascular risk factors such as obesity and associated diabetes are now beginning to impact on CHD mortality. This highlights a pressing need to tackle the challenge of increasing obesity in the Scottish population.

The fall in mortality from stroke has been more consistent. Mortality from stroke in the under 75s has fallen substantially from 37 deaths per 100,000 in 1995 to 20 deaths per 100,000 in 2006 (Figure 2). If this trend continues, the 2010 target of a 50% reduction in mortality in this age group should be met. However, the continuing increase in the proportion of older people in the Scottish population will mean the number of people of all ages in Scotland suffering a stroke will continue to increase unless the incidence of stroke in the over 75s is reduced.

Figure 1: Mortality rates in Scotland from 1995 to 2006 for coronary heart disease for ages under 75

Source: GRO(S)

Figure 2: Mortality rates in Scotland from 1995 to 2006 for stroke for ages under 75

Source: GRO(S)

Behind these population trends there is also a worrying gap in cardiovascular health between the more affluent and the more deprived people of Scotland. See Figures 3 and 4.

What more could be done to accelerate the current overall decline in CVD mortality and narrow the gap which persists between mortality rates in rich and poor communities?

The recent Better Health, Better Care action plan ¹ emphasises the crucial need to reduce the significant widening health inequalities in Scotland. Current differences in life expectancy and health in Scotland, with people in the most affluent areas of the country living several years longer than those in the most deprived areas need to be tackled. The Scottish Government is working to break the link between early life adversity and future adult disease, and to support individual behaviours that promote good physical and mental health and wellbeing. The report of the Ministerial Task Force on Health Inequalities Equally Well² published in June 2008 demonstrates the Scottish Government's commitment to tackling health inequalities. Current health improvement policies aim to change the average behaviour of the Scottish population by focussing on reducing poverty, encouraging healthy lifestyles, including taking more exercise and eating more fruit and vegetables while reducing intake of salt, saturated fats and alcohol. Increasingly health improvement policies are also targeting those populations that are at greatest risk of future ill health and often least able to access health improvement support.

Impact of Health Improvement Measures

The Scottish Government is funding £56 million to support implementation of the recently published policy Healthy Eating, Active Living: An Action Plan to Improve Diet, Increase Activity and Tackle Obesity³. It is also building on Scotland's historic 2005 legislation banning smoking in enclosed public places and in May 2008 published a smoking prevention Action Plan Scotland's Future is Smoke Free. This has radical new proposals such as substantially reducing the availability, affordability and attractiveness of cigarettes to young people and further reduce the number of people exposed to tobacco smoke. Improving the pattern in the population of blood pressure, blood fats, diet, smoking and physical activity by even a small proportion will have a big impact on the numbers in the overall population having heart attacks and strokes. Table 1 illustrates the potential reduction in incidence of major cardiovascular events in the 10 years following treatment of middle aged men who are identified as high risk.

Figure 3: Coronary heart disease standardised mortality ratios by SIMD deprivation decile, 2002-2006

Source: ISD Scotland; GRO(S)

Figure 4: Cerebrovascular disease standardised mortality ratios, by SIMD deprivation decile, 2002-2006

Source: ISD Scotland; GRO(S)

Table 1: Potential reduction in incidence of major cardiovascular events in subsequent 10 years by treatment of middle-aged men identified as at high risk

(Combined treatment: Statin, BP lowering drug and aspirin)

Based on Table 18.8: Stroke: practical management. 3rd Edition. Warlow C et al. Blackwell 2008. ISBN 978-1-4051-2766-0 ⁴.

GPs and other professionals providing day-to-day services can opportunistically identify individuals with modifiable risk factors and provide medical treatment and offer lifestyle support to reduce future risk of major cardiovascular events. It is also possible to systematically screen populations known to be at higher risk. This approach underpins the Keep Well Programmes which provides anticipatory care for those at higher risk of CHD and diabetes. The programmes invite 45-64 year olds within deprived communities to attend a health check and offer those found to be at higher risk medical treatment and support to tackle smoking, poor physical activity and other health related behaviour. The first wave of Keep Well programmes are working in Community Health Partnerships in Greater Glasgow and Clyde, Lanarkshire, Tayside and Lothian NHS Board areas. A second wave will begin shortly in NHS Grampian, NHS Ayrshire and Arran, and NHS Fife. A related programme, Well North, in the north of Scotland aims to widen the reach of anticipatory care to remote and rural areas. The learning points from the evaluation of these first programmes have been shared widely across Scotland.

It is essential within Keep Well that GPs and others are able to estimate an individual's future risk of CVD. The Keep Well pilot in south Glasgow is now assessing the impact of a new risk-factor calculator, " ASSIGN", developed as part of the SIGN (Scottish Intercollegiate Guideline Network) guideline 97: Risk Estimation and the Prevention of CVD⁵ published in 2007. ASSIGN⁶ is based on the well-established "Framingham" risk score developed from research into cardiovascular disease in the population of Framingham, USA, over a period of many years. The new ASSIGN calculator measures risk on the basis of key factors for each individual such as age, sex, blood pressure, smoking history, and blood fats. ASSIGN also includes a measure of social deprivation - the Scottish Index of Multiple Deprivation ( SIMD) - as well as family history. This means that for the first time Scottish people will be able to have a full assessment of CHD risk, taking account of the influence of both deprivation and family history (which also acts as a proxy for ethnic background). Those assessed by ASSIGN as having more than 20% risk of CVD over 10 years should be offered lifestyle support such as smoking cessation and dietary advice and be considered for treatment with fat-lowering drugs (statins) and blood thinning drugs (such as aspirin). We know from previous surveys that approximately one-third of people over the age of 40 in Scotland will be in this risk category. The number eligible for drug treatment and health improvement support is likely to increase through the use of ASSIGN, and the expected reduction in CVD risk in that population should reduce future death and disability from CHD and stroke.

Strategies such as Keep Well by targeting sections of the population at greatest risk could reduce the average blood pressure of middle-aged men leading to a potential 16% reduction of the incidence of stroke in Scotland. If all main risk factors were optimally reduced in the whole Scottish population it has been estimated that 70% of deaths attributed to stroke could be avoided.

An important cause of stroke is atrial fibrillation (a type of irregular heart beat) which leads to the development of blood clots in the heart which then travel to the brain to cause strokes. Identifying those over 40 years of age who have atrial fibrillation and treating them with antithrombotic (anti- clotting) treatments such as warfarin or aspirin could further reduce the number of strokes by about 7%. This equates to 960 fewer strokes per year in Scotland. Of these 960 people, 320 would have died and 320 left with significant disability. Table 2 illustrates the estimated effect of treating this group on the number of strokes occurring in Scotland.

A "Resource Impact Assessment" ⁷ of the recent CVDSIGN Guidelines estimated the potential number of lives saved over 5 years by implementing the guidelines. Table 3 shows the estimated impact through reducing smoking rates, prescribing statins in high-risk patients and better uptake of healthy eating. Health professionals and other staff in primary health care and hospital services will be integral to delivering this reduction in CVD risk in the Scottish population. The estimated number of lives that would be saved in Scotland over 5 years by the implementation of the SIGN Guidelines is nearly 3,500.

Table 2: Estimated reduction in the incidence of strokes in Scotland following treatment with antithrombotic drugs of those aged 40+ with atrial fibrillation ( AF)

Based on Table 18.9: Stroke: practical management. 3rd Edition. Warlow C et al. Blackwell 2008. ISBN 978-1-4051-2766-0 ⁴.

Table 3: Estimated lives years saved in Scotland over 5 years by full implementation of primary prevention element of CVDSIGN Guidelines

Source: SIGN Impact Assessment ⁷

Impact of clinical treatment and interventions

Stroke

Even if the person has had a stroke, there is still significant scope to reduce the subsequent risk of death and disability. An increasing number of interventions are becoming widely available to reduce mortality, improve survival and enable recovery after a stroke. Interventions can also reduce the risk of future strokes and other vascular events. Table 4 illustrates the estimated impact on acute stroke in the Scottish population in a number of these interventions.

Table 4: Estimated effect of interventions for acute stroke on (a) death and (b) death or dependency in the 11,626 patients estimated to have a stroke each year in the Scottish population

Based on Table 18.2: Stroke: practical management. 3rd Edition. Warlow C et al. Blackwell 2008. ISBN 978-1-4051-2766-0 ⁴.

It is now widely accepted that patients with strokes admitted to dedicated hospital Stroke Units have better survival and recovery than those treated on general wards. The 2004 clinical standards for Stroke Services ⁸ include the requirement that at least 70% of patients with a stroke admitted to hospital should be cared for in a stroke unit within the first day of admission. Over 10,000 people are admitted to hospital for stroke each year in Scotland meaning that over 7,000 patients should be admitted to a stroke unit annually. The recent Scottish Stroke Care Audit ⁹ (Table 5) shows steady progress towards this target from 2005 to 2007. When the 70% target is achieved, deaths from stroke should have fallen 12% compared to the early 1990s when care in a stroke unit was the exception.

'It is now widely accepted that patients with strokes admitted to dedicated hospital Stroke Units have better survival and recovery than those treated on general wards. The NHSQiS 2004 clinical standards for Stroke Services include the requirement that at least 70% of patients with a stroke admitted to hospital should be cared for in a stroke unit within the first day of admission.'

Table 5: Percentage of patients with stroke admitted to a Stroke unit in Scotland at any time and within first day of admission

Source: Scottish Stroke Care Audit 2008 National Report⁹

Table 6 summarises the potential impact on recurrent stroke of secondary prevention of stroke by use of antithrombotics, reduction of blood pressure, lowering blood cholesterol and carotid endarterectomy (surgical removal of blood clots).

Providing thrombolysis (clot-busting) treatment for all stroke patients who might benefit has been identified by the National Advisory Committee for Stroke ( NACS) as a development priority for stroke services in Scotland. While trials of thrombolysis in stroke have not shown statistically significant reduction in deaths there is strong evidence that thrombolysis reduces disability preventing long-term disability in 1 in 10 patients.

Coronary Heart Disease ( CHD)

Five SIGN Cardiovascular Guidelines (93-97) ¹⁰ published in 2007 cover:

• Risk Estimation and Prevention
• Acute Coronary Syndrome (heart attacks)
• Cardiac Arrhythmias in CHD
• Management of Chronic Heart Failure
• Management of Stable Angina.

The Guidelines created a new landmark in evidence-based management of these conditions, but also highlighted gaps in current service provision and therefore potential unmet need. For this reason, SIGN developed the Resource Impact Assessment referred to earlier. This assessment will help NHS Boards plan for the phased implementation of the Guidelines. Table 7 summarises the potential clinical benefits including the number of lives saved over a 5-year period. It also links the associated costs of implementation to show costs per year of life gained ( YLG). Implementing the SIGN recommendations would, over a 5-year period, prevent an estimated 7,200 premature CVD deaths and avoid over 27,000 major vascular events such as heart attacks and strokes. This is equivalent to a 9% reduction in both the current CVD mortality rate and CVD event rate. As a direct result NHSScotland could potentially release over 60,000 bed days, costing some £20 million annually, for alternative uses. The costs per Year of Life Gained range across the guidelines from £3,700 for heart failure nurses to £190,000 for all secondary prevention. The resource impact assessment estimates that providing statins to asymptomatic individuals at high risk of CVD provides about 37% of the mortality benefit and 30% of the potential clinical and related resource released.

'Implementing the SIGN recommendations would, over a 5-year period, prevent an estimated 7,200 premature CVD deaths and avoid over 27,000 major vascular events such as heart attacks and strokes. This is equivalent to a 9% reduction in both the current CVD mortality rate and CVD event rate. '

Table 6: Estimated impact of interventions to prevent recurrent strokes on the estimated 11,626 strokes occurring annually in the Scottish population

Based on Table 18.4: Stroke: practical management. 3rd Edition. Warlow C et al. Blackwell 2008. ISBN 978-1-4051-2766-0 ⁴.

Table 7: Impact of SIGN Guidelines Implementation

Based on impact assessment of SIGN Guidelines (some figures are combined and rounded for simplification)
STEMI = ST elevation myocardial infarction
NSTEMI = non ST elevation myocardial infarction

NHS Boards are working together through the three Regional Planning groups to address some of the identified gaps in interventional services. Examples of regional provision of new services include cardiac resynchronisation therapy ( CRT) (which helps patients with heart failure) across Scotland. An Inter-Regional planning group is now working to ensure optimal reperfusion therapy across Scotland for myocardial infarction (heart attacks due to blood clots in the coronary arteries). These treatments include primary PCI (removing the clot by use of a small catheter inserted into the arteries in the neck) or thrombolysis ("clot busting" by drug treatment). Other gaps in present service provision will undoubtedly need to be addressed in due course to ensure full implementation of the SIGN Guidelines and the subsequent reduction in death and disability from CHD and stroke in Scotland.

Conclusion

The health improvement measures and interventions described above have the potential to save up to 10,000 lives from cardiovascular disease each year in Scotland, if optimally applied.

The revised Coronary Heart Disease and Stroke Strategy for Scotland, which will be published shortly, reaffirms the position of CHD and stroke as national clinical priorities. It seeks to respond to a number of challenges, not least to respond to new developments in evidence reflected in the SIGN Guidelines, and to accelerate the downward trend in amenable mortality from CVD observed in Scotland over many years.

'The health improvement measures and interventions described above have the potential to save up to 10,000 lives from cardiovascular disease each year in Scotland, if optimally applied.'

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