Importance of Screening to Prevent Heart Attacks

The prevalence of coronary heart disease is increasing owing to improved survival and an aging population. Primary prevention should be targeted at those individuals with the highest global risk. Mass screening of the whole population to identify those at high risk is a relatively low-yield, high-cost option. Alternatively, we could target screening at population subgroups in which high-risk individuals are over-represented, such as those with a family history and deprived communities. This higher yield, lower cost option would nonetheless achieve good coverage of high-risk individuals in the general population. Surveys suggest that we currently have high levels of unmet need amongst those who would benefit most from primary prevention. Urgent action is required to address this.

Why?

Cardiovascular disease remains the main cause of death in the UK, accounting for more than a third of all deaths [101]. It is also the main cause of premature death (31% of premature deaths in men; 23% in women). Each year, cardiovascular disease accounts for over 208,000 deaths and 57,000 premature deaths. Reassuringly, mortality from coronary heart disease is falling in the UK, in common with other Western countries. By contrast, the prevalence of coronary heart disease is increasing [102,103], owing to a combination of improved survival and an aging population. Therefore, in spite of declining mortality, the economic burden has increased. Cardiovascular disease costs the UK health service approximately £15,000 million per annum, in addition to non-health service costs of £6200 million arising from lost productivity and £3100 million required to fund social care [101]. Increasing prevalence of obesity and Type II diabetes will add further to the burden of cardiovascular disease. Our approach to cardiovascular disease needs to evolve in response to its changing epidemiology. Previous efforts to improve survival after acute events have been effective. However, greater efforts are now needed to stem the worrying increase in chronic disease via primary prevention.

How?

The risk of developing cardiovascular disease depends on the net effect of multiple risk factors, many of which can be modified via lifestyle changes and therapeutic interventions. Our approach to the prevention of cardiovascular disease has evolved. In the past, primary prevention was based on identifying and treating individuals with a very high level of a single risk factor, such as high blood pressure.

Whilst effective at reducing the individual‘s risk, this is a relatively ineffective population strategy, since individuals with only moderately raised levels are more numerous and, therefore, account for the majority of events. In addition, targeting interventions on the basis of individual risk factors ignores the multifactorial nature of cardiovascular disease. The preferred approach is now to target individuals with an increased global risk, usually due to a combination of risk factors. Targeting interventions on the basis of global risk is more than twice as effective as a population strategy [1].

Who?

In order to treat those individuals in the general population who have high global risk of developing cardiovascular disease, we must first identify them. This can either be done via mass screening of the whole population, or targeted screening of a subgroup in which high-risk individuals are known to be over-represented. Global risk of coronary heart disease is usually derived from validated risk scores, such as assessing cardiovascular risk using Scottish Intercollegiate Guidelines Network (ASSIGN) or the QRESEARCH primary care database (QRISK) [2,3], with interventions being targeted at those with a greater than 20% risk of cardiovascular events over 10 years. However, calculating risk scores requires information on a number of risk factors, such as age, sex, BMI, cholesterol concentration, diabetes, family history, smoking status, deprivation category and blood pressure. Electronic recording of such information in primary care has improved, but, as yet, there is no system for ensuring that all necessary information on the whole UK population is collected and recorded. Opportunistic capture of this information when patients visit primary care for another reason is feasible. However, some subgroups of the population, such as middle-aged men, attend their general practitioner infrequently. Information can be derived during occupational health checks, but these are undertaken on a minority of people and socioeconomically deprived individuals are under-represented. The Oxford and Collaborators Health Check (OxCheck) and British Family Heart studies demonstrated that inviting unselected individuals for primary-care screening was feasible [4]. However, the yield of unselected screening is low. The investigators reported borderline cost–effectiveness [5], but the overall cost of such an approach may nonetheless be prohibitive [6].

An alternative is to screen subgroups of the population in which high-risk individuals are known to be over-represented, such as socioeconomically deprived communities or those with a family history. Family history is a strong predictor of cardiovascular risk. Siblings of patients suffering premature coronary heart disease have at least double the risk of cardiovascular events, owing to a combination of shared lifestyle risk factors and genetic predisposition [1,7–9]. Partners are also at increased risk as a result of shared lifestyle [10]. Family members have an increased prevalence of risk factors such as hypertension, dyslipidemia and smoking [11], which can be modified by educational and therapeutic interventions. Family history is a good proxy measure of global risk of premature coronary heart disease. The 14% of families who have a history of premature coronary heart disease account for 48% of all coronary heart disease events and 72% of premature events [12]. Hence, any preventative or treatment interventions targeted at family members would provide good coverage of high-risk individuals in the general population. We recently calculated that more than a third of admissions for premature myocardial infarction could potentially be prevented if we adopted a strategy similar to that used for familial cancers, by using admission for premature myocardial infarction as the trigger to approach and screen family members [13]. Compared with unselected screening of the general population, this approach would produce higher yield and be more cost effective. Furthermore, asymptomatic high-risk individuals may be motivated to modify their lifestyle and comply with medication, if approached when a relative is receiving hospital treatment.

When?

Now. Guidelines already advocate primary prevention among those with a high global risk, and some specifically recommend screening of first-degree relatives [11–15]. In spite of this, studies consistently demonstrate an unmet need among high-risk individuals. In particular, family members are characterized by a lack of awareness of their increased risk and a high prevalence of unrecognized or inadequately treated risk factors. In view of the increasing prevalence of chronic cardiovascular disease and the predictable consequences of increasing obesity and diabetes, action is required now.

Conclusion

Mortality from acute coronary events is falling. However, the population burden from chronic cardiovascular disease is increasing. We need to respond to this by effective primary-prevention strategies. Preventative strategies need to take cognizance of the multifactorial nature of cardiovascular disease and target interventions at those with the highest global risk. Identifying such individuals from the asymptomatic general population is a difficult task and the cost may be prohibitive. Family history is a good proxy measure of global risk. Screening the family members of patients who present with premature coronary heart disease is a higher yield, lower cost option that would provide good population coverage of those at high risk.

Future perspective

Research into cardiovascular disease has already identified important targets for modification and effective treatments to do so. However, we remain relatively ineffective at translating evidence into practice. Future research should focus on innovative, cost-effective methods of identifying asymptomatic individuals in the general population at high global risk who would benefit from risk-factor modification, particularly those who infrequently come into contact with the health service, such as middle-aged men. It is likely that a multifaceted approach is required; combining improved awareness in the general population with interventions targeted at high-risk subgroups (such as family members and deprived communities). We need to improve the capture and sharing of electronic data within the National Health Service (NHS) as well as exploring how information collected in other locations, such as private pharmacies, can inform the process.

Executive summary

•	The prevalence of cardiovascular disease is increasing owing to improved survival, an aging population and an increase in obesity and diabetes.

•	Improved primary prevention is required to stem this trend.

•	Primary prevention should be targeted at those individuals with the highest global risk, rather than on the basis of individual risk factors.

•	Mass screening of the whole population, whilst ideal, is a relatively low-yield, high-cost option.

•

Targeted screening of population subgroups in which high-risk individuals are over-represented, such as those with a family history of premature coronary heart disease or deprived communities, is a higher yield, lower cost option and will achieve good coverage of high-risk individuals in the population as a whole.

•	Surveys suggest high levels of unmet need amongst those who would benefit most from primary prevention. Action is required to address this.

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.