Michaela Nuttall, MSc, RN, DipN. is CHD Co-ordinator, Bromley Primary Care Trust, Farnborough, Kent.
Coronary heart disease is the single most common cause of premature death in the UK. Every year, more than 1.4 million people suffer from angina, there are 300 000 heart attacks and over 110 000 people die from heart problems. Although CHD-related mortality rates are declining, it still accounts for more than a quarter of all deaths (British Heart Foundation, 2001), many of which are preventable.
The concept of CHD prevention has increasingly gained acceptance in cardiovascular medicine. It is part of a continuum, with secondary prevention at one end, primary prevention for those at high risk in the middle and population-based primary prevention at the other end.
The prevalence of CHD stands at 3-5% of the population (Gray et al, 2000), so more than 95% of people in the UK would benefit from primary health prevention. Simple treatments and lifestyle changes can reduce the risk of cardiovascular events in people with CHD, as well as in those at high risk of developing it (Wood et al, 1998).
There are great differences in the advice and treatment for CHD offered nationwide, an issue the National Service Framework for Coronary Heart Disease (DoH, 2000) aims to tackle. It puts the concept of risk at the core of primary prevention, stressing that preventive care should be matched to an individual’s risk of developing CHD.
This paper pulls together evidence from various electronic databases, including Ovid, Medline, Cinahl, the British Nursing Index, and the Cochrane Library Database of Systematic Reviews and Database of Abstracts of Reviews of Effectiveness. A combination of key words - ‘coronary heart disease’, ‘primary prevention’ and ‘general practice’ or ‘primary care’ - was used to search the databases for the years 1996-2002.
The National Service Framework
The NSF on coronary heart disease provides a high-quality framework specifying effective interventions and models of care within the government’s modernisation programme. It promotes clear standards for the prevention and treatment of CHD, with the aim of improving the quality of care and access to it (DoH, 2000).
The Government’s blueprint for tackling heart disease recognises the importance of prevention and primary care alongside more specialist services. Its strategies range from preventing people from getting heart disease to managing and treating those diagnosed with CHD. The aims are to reduce onset, progression and death from CHD.The NSF establishes clear clinical areas for prevention and treatment of CHD (Box 1), focusing among other issues on CHD prevention in primary care. It aims to guide general practice towards helping both people with clinical evidence of CHD and those at high risk of developing it to reduce the risks of CHD.Standard four focuses on primary prevention of CHD in people at high risk. It promotes practice-based screening for risk factors and treatment based on risk, where appropriate (Box 2).
For people who do not have CHD, attendance in hospital or at the GPs should be seen as an opportunity to assess their risk of having a cardiovascular event in the next 10 years. Primary care is ideally placed to measure patients’ CHD risk, as GP surgeries already hold a minimum amount of information about patients in medical records.
Although nurses in all settings have the chance to assess and advise patients on CHD risk factors, those in primary care are particularly well placed. They have access to people at high risk through established clinics for people with diabetes and hypertension. The role of practice nurses in the prevention of CHD is potentially enormous. Extra support and education will be needed to develop this role.
Coronary heart disease risks
The onset of CHD cannot be explained by any single risk factor. A combination of factors can increase the risk steeply (Wood et al, 1998), although this depends on the specific factors present and their inter-relationship. It is important to distinguish between those risks that can cause CHD and a person’s risk of developing CHD.
The NSF on coronary heart disease recommends that risk assessment is calculated using the joint British recommendations on CHD prevention (Wood et al, 1998). These are the culmination of a collaborative project by the British Cardiac Society, the British Hyperlipidaemia Association, the British Hypertension Society, and the British Diabetic Association. The recommendations offer two ways to calculate risk: using the published tables or the Cardiac Risk Assessor Program software. The software option is undoubtedly ideal for use in primary care as it can be built into patient record templates and calculated automatically.
However, the risk charts must not be used for people who already have the following:
- Established CHD
- Other atherosclerosis
- Familial hypercholesterolaemia
- Malignant hypertension.
Establishing a high-risk register
As mentioned above, it is important to take a systematic approach to identifying people at high CHD risk. The formal risk assessment should be carried out for all those who have at least one major risk factor. The NSF on coronary heart disease recommends a structured approach to targeting people known to be at risk - in particular, those who have diabetes and/or hypertension.
These disorders are more prevalent in some populations than others: for example, people of South Asian descent have a higher incidence of diabetes than those of Caucasian descent (DoH, 2000). This should, however, not exclude opportunistic assessment, as both have a role in general practice. A computerised or paper search of registers of patients with diabetes and hyper-tension will identify those potentially at risk.
Patients with a calculated risk of CHD of more than 30% need to be prioritised for advice and interventions. The establishment of a high-risk register will ensure that effective, systematic care can be delivered. The register must be maintained, and reasons for removal include CHD diagnosis, transferred to the CHD register, moving away or death. Even when the risk has been reduced to less than 30%, the patient should remain on the register for regular advice and treatment.
Many people could benefit from lifestyle and pharmacological interventions: for example, advice from the GP can be effective in achieving smoking cessation (Russell et al, 1979), which can be enhanced by nicotine replacement therapy (Raw, 1998). In people with hypercholesterolaemia, the use of cholesterol-lowering drugs can reduce the risk of coronary events by up to 30% (Anon, 1996). Lowering blood pressure can also reduce the development of CHD (Rouse and Adab, 2001).
However, when all these interventions have been combined in single multiple-risk factor trials the results have been modest (Imperial Cancer Research Fund, 1995; Family Heart Study Group, 1994). The Cochrane Library reviewed multiple risk-factor interventions for primary prevention of CHD (Ebrahim et al, 2002) and concluded that effective interventions on a general population basis would be mostly ineffective and very costly.
However, it showed that people with hypertension were likely to benefit from counselling and education, and effective drug therapy. This further supports the notion of targeting of health promotion activities at high-risk individuals.
Lifestyle advice - Everyone, irrespective of individual CHD risk, can benefit from lifestyle advice. However, this approach needs to be targeted for financial and workload reasons. For people whose CHD risk is less than 30%, pharmacotherapy is not justified and lifestyle intervention should be the only approach offered.
Pharmacological management - Pharmacological management for primary prevention is similar to that for secondary prevention. Initially, treatments should be targeted at people at greatest risk. Those with a CHD risk of more than 30% over 10 years (DoH, 2000) should be offered the following:
- Advice and treatment to maintain blood pressure (BP) below 140/85 mmHg
- Statins to lower serum cholesterol, either to below 5mmol/l (LDL-C <3 mmol/l), or by 30%, whichever is greater
- Meticulous control of BP and glucose in people who also have diabetes: BP less than 130/80mmHg
- Aspirin (75mg) for people over 55 years who have either well-controlled hypertension or are at high risk of CHD.
All the above interventions contribute to minimising an individual’s risk of coronary death or major coronary event. Structured care provision will ensure appropriate treatment (Box 3). The NSF advises that protocols be locally written for managing people at high risk of developing CHD and should include patient assessment, the structure (the computer template used), lifestyle advice, therapy, indications for referral, arrangements for follow-up and review, and clinical audit.
The NSF suggests that systematic care can be delivered in general practice in a number of ways:
- Routine consultations, with the use of paper or electronic protocols and templates
- Special ‘practice cardiac prevention clinics’ that would typically be nurse-run
- Special ‘multipractice or PCG/PCT cardiac prevention clinics’, typically nurse-run.
Primary care is ideally placed for delivering effective primary prevention. The NSF on coronary heart disease gives clear advice on how to reduce risk of CHD, and a systematic approach for doing so. Yet general practices are just that - general - and CHD is one of the many diseases they deal with. Targeting people at highest risk would be the most effective use of time and resources.
Anon. (1996) West of Scotland coronary prevention study: identification of high-risk groups and comparison with other cardiovascular intervention trials. Lancet 348: 1339-1342.
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Department of Health. (2000) National Service Framework for Coronary Heart Disease. London: The Stationary Office.
Ebrahim, S., Davey Smith, G. (2002) Multiple risk factor interventions for primary prevention of coronary heart disease (Cochrane Review). The Cochrane Library, Issue 1. Oxford: Update Software.
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