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A nurse-led approach to secondary prevention of CHD in primary care

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Shirley Ann Clare, BA (Hons), RN.

Healthy Heart Service Co-ordinator, St Helens and Knowsley Community NHS Trust

Advances in technology and pharmacological treatments have failed to lead to a decline in the prevalence of coronary heart disease (CHD), although they have brought about a reduction in the overall mortality rate.

Advances in technology and pharmacological treatments have failed to lead to a decline in the prevalence of coronary heart disease (CHD), although they have brought about a reduction in the overall mortality rate.

In a study of the contributions of modern cardiovascular treatments and risk factor changes to the decline in CHD mortality in Scotland between 1975 and 1994, Capewell et al (1999) found that 40% of the reduction was attributed to treatments for acute myocardial infarction, heart failure and revascularisation, and 52% was attributed to measurable risk factor reduction (smoking, cholesterol and blood pressure) as well as changes in deprivation.

Studies in Finland between 1972 and 1992 have produced similar results and have shown a decline in the CHD mortality rate by 55% in men and up to 68% in women. This was attributed to dietary changes, which have led to a decrease in serum cholesterol levels, together with smoking cessation and improved management of blood pressure (Pietinen et al, 1996).

In 1998 CHD accounted for 137 153 deaths in the UK (British Heart Foundation, 2000). It imposes a high personal and socio-economic cost not only to the individual but also to his or her family and society as a whole. However, the incidence of CHD is not spread evenly; regional variations in death rates show that there is a significantly higher rate of mortality in the north of England, Northern Ireland and Scotland. This is reflected in the fact that St Helens and Knowsley have a standard mortality ratio that is 40% higher than the national average.

Inequalities and deprivation play a major part in determining cardiac health. The relationship between social status and CHD is well established, showing the more socially disadvantaged being at a higher risk (British Heart Foundation, 2000). Compared with other geographical areas, St Helens and Knowsley are among the 50 most deprived, with Knowsley being ranked fifth and St Helens 38th out of the 354 districts in England.

Secondary prevention of CHD
Health promotion and prevention are core areas within government strategies to improve the general health of the population (Department of Health, 1997; 2000).

In 1996 the results of the ASPIRE Survey (1996) revealed that the follow-up monitoring and treatment of risk factors in patients with established heart disease was clearly deficient. The report concluded that the risk of future cardiac events could be reduced with effective lifestyle interventions, control of blood pressure, management of cholesterol and the appropriate use of cardioprotective drugs. Work by Campbell et al (1998) and Van de Weijden and Grol (1998) also revealed that secondary prevention in primary care was at a suboptimal level.

St Helens and Knowsley cardiovascular strategy
Before the publication of the National Service Framework for CHD, individual GPs varied their approach to the management of the disease. To address this and the issues highlighted above, during 1996/97 St Helens and Knowsley Health Authority developed a local cardiovascular strategy (1996). The purpose of this was to:

- Reduce premature deaths from CHD

- Preserve patients' ability to live independently

- Improve quality of life for patients with CHD by reducing or controlling symptoms

- Identify those residents with a genetic disposition to developing CHD and target with primary prevention.

This was to be achieved by delivering integrated care for patients with existing CHD. The term integrated implies a shared and reciprocal pathway that links primary, secondary and tertiary care. We have adopted this concept of care to divide the work into understandable components that relate to our current service configuration. This has subsequently become one of the most comprehensive cardiac programmes in the country.

The chronic care pathway for CHD consists of care received mainly in the community, and is aimed at reducing the number of further episodes of severe chest pain or myocardial infarction. As part of this new initiative, specialist nurse-led clinics were established within GP surgeries in order to provide a systematic and structured review of patients with existing CHD.

The Healthy Heart Service employs a full-time co-ordinator and 10.5 whole time equivalent (WTE) cardiac nurse advisers, making it the largest community-based cardiac nurse team in the country.

Nurse-led clinics
Nurse-led clinics are becoming recognised as an effective way to provide specialist advice and continued support to patients (Castineira et al, 1999; Rotchell, 1999; Sawyer, 2000). A trial in Scotland by Campbell et al (1998) suggested that nurse-led CHD clinics are practical to implement in general practice and are effective in providing secondary prevention. The St Helens and Knowsley initiative was in some ways similar to the Scottish trial, differing only in the use of specialist cardiac nurses to run the clinics.

Adopting an evidence-based approach
The overall aim of the cardiac nurse is to provide a high-quality service that is responsive to patients' needs and consistent in its approach. The main objective of the clinics is to ensure that patients benefit from evidence-based treatments known to improve outcome. These included pharmacological management with low dose aspirin and the use of statins as appropriate to reduce cholesterol to less than 5.0mmol/l and verify patient's compliance in taking medication, along with advice on healthier lifestyles. Incorporated in the review is calculating body mass index (BMI) and blood pressure monitoring. Also documented was the severity of the patient's angina. This was determined by using the Canadian Cardiovascular Society Classification (Table 1), which enables the nurse to assess the severity of the patient's symptoms and disability (Wood et al, 1998).

Pharmacological interventions
The benefits of using anti-platelet therapy in patients with CHD to reduce vascular events and mortality are well documented (Antiplatelet Trialists' Collaboration, 1994). There is also compelling evidence available from three major trials (Scandinavian Simvastatin Survival Study Group, 1994; CARE (Cholesterol and Recurrent Event Trial), Sacks et al, 1996; LIPID Study Group, 1998), which indicate the efficacy of statins in the reduction of recurrent coronary events and mortality in patients with CHD.

Lifestyle interventions
Given the current high prevalence of sedentary lifestyle and the number of smokers within this group of patients, there is little doubt that considerable health gains would arise if individuals changed their behaviour in relation to diet, smoking and physical activity. Evidence to support the proven effectiveness of lifestyle changes was demonstrated by Ornish et al in 'The Lifestyle Trial' (1998). This trial illustrated that intensive lifestyle changes may lead to regression of coronary atherosclerosis after one year.

Changing the behaviour of patients is a long-term challenge and commitment. To ascertain a patient's willingness to change and to promote healthier lifestyles the 'stages of change' model is applied (Health Education Authority, 1994; Prochaska and DiClemente, 1989) (Figure 1) alongside motivational interviewing techniques. This model was originally used in work on addictive behaviour and categorises individuals according to different stages of change.

The advantage of using this model is that it enables the person using it to identify where on the cycle of change the patient is and ensures that the appropriate input with regard to resources, skills and support is given (Rollnick et al, 1999).

Quality assurance
To ensure good practice and consistency, tools were developed to aid the review process, along with patient information leaflets. These include a leaflet on angina, which provides information on cardiac drugs (aspirin, beta blockers, ACE inhibitors, diuretics and calcium channel blockers) and different lifestyle activities (smoking, diet, alcohol and physical activity).

A hand-held card was also devised to encourage patients to take responsibility and ownership of their treatment. The card was also to be used as an aid to prompt continued care and provide guidance for follow-up by other health-care professionals.

Selecting patients for review
The estimated population of CHD patients in St Helens and Knowsley Health Authority area is 10 000. Initially the cardiac nurses worked with the practice team to develop CHD patient disease registers. These were established mainly from nitrate searches, combined where possible with existing registers, but these were limited in most practices.

After compiling the list, it was reviewed by the GP to confirm the patients' suitability for review and to identify an initial target group. These groups varied between practices and included patients aged under 50 years, those post-myocardial infarction or revascularisation and patients who had not been prescribed aspirin. To date, CHD clinics have been established in 74 out of 77 GP practices, and as of the end of September 2001 over 6500 patients have undergone an initial review.

Results of patients reviews
A database has been compiled, which includes the results of the 5300 patient reviews undertaken by the time of the data analysis (January 2001). Of these, 2859 patients have also received a follow-up review. This large sample of patients undergoing initial and follow-up review gives the Healthy Heart Service a clear understanding of the effectiveness of the interventions offered.

Cardiac nurses have collected data on the five interventions. These have been downloaded onto an Access database and analysed using SPSS. Cardiac nurses gave a subjective assessment of the dietary and activity status of the patients based on the answers to a number of questions. Data on smoking status were collected via questions asked of the patient rather than via carbon monoxide monitors. In addition, data were collected on the cholesterol measurements of heart patients, angina grade, blood pressure and BMI.

Of the 2859 patients for whom we currently have an initial review and follow-up data, 1775 (62.1%) were men and 1084 (37.9%) women. Patients' ages ranged from 25 to 91. As might be expected, the majority of patients were aged between 55 and 74.

For all patients given an initial review and a follow-up appointment, there were improvements in both the medication received and lifestyle behaviour. Table 2 shows before and after scores for the five interventions.

As well as improvements in each of the six interventions, the cardiac nurse-led clinics also appear to have initiated a definite improvement in other outcomes related to angina grade, cholesterol, hypertension and body mass index (Table 3).

Before the intervention, 48.1% of patients with heart disease had an angina grade of less than 2. After intervention this had increased to 59.6% (chi-squared=83.6 df=5, significance level=0.00). Similarly, more patients had a cholesterol level less than 5.0mmol/l, while the percentage of patients classed as 'hypertensive' (blood pressure above 140/85mmHg) had decreased from 44.1% before intervention to 33.4% after intervention (chi-squared=58.9 df=1, significance level=0.00). The percentage of patients with a body mass index above 30 decreased slightly from 29.3% to 25.7%.

Interventions were effective in men and women. Measures such as percentage of cardiac patients with an angina grade of less than 2 appear to be very successful in female patients. Before intervention 44.5% of female patients had an angina grade of less than 2; this increased to 58.3% after intervention (Table 4).

Analysis by age group shows that some interventions were more successful in younger patients than others. The percentage of cardiac patients with hypertension increased with age, both before and after intervention. After intervention 12.2% of those aged under 45 had hypertension compared to 44.8% of those aged 75 and over. Some age groups such as those aged 64 to 74 (48.6% to 35%) and those aged 45 to 54 (37.9% to 22.6%) had experienced bigger falls in the percentage of cardiac patients with hypertension than others (either very young or very old cardiac patients). Dietary habits had improved in all age groups.

Older patients were much less likely to smoke than younger patients. After intervention, 30.2% of cardiac patients aged under 45 continued to smoke compared to just 10.5% of those aged 75 and over. In all age groups, smoking prevalence fell by around 8%.

In common with the figures for hypertension, those patients in the 'middle' age groups were more likely to be on aspirin, both before and after intervention, than the younger or older cardiac patients. Just under 90% of patients aged 45 to 54 were on aspirin after intervention, compared to 79.4% of those aged 75 and over.

Differentials in the percentage of patients on statins existed before intervention when 51.9% of cardiac patients aged under 45 and 41.8% of those aged 45-54 were on statins. This compared with just 21.1% of those aged 75 and over who were on statins before intervention.

In the younger age groups a very small increase was seen in the number of patients on statins: 37% to 33.5% in 55-64-year-olds. A larger increase was seen in those aged 75 and over, from 21.1% to 34.6%.

Conclusion
The task of systematically reviewing all patients with established heart disease is a significant but necessary piece of work and requires a commitment from all those in the primary care team.

Before intervention there was some variability in the provision of optimal care, particularly in the care provided to different age groups. Of note are figures on the provision of statins. Before intervention older patients were half as likely to receive statins as younger cardiac patients.

Cardiac nurses have successfully increased uptake of each intervention, and it appears that this has improved outcomes for cardiac patients. However, some figures, such as the number of younger cardiac patients who continue to smoke, remain an area of concern. In addition, there remains an inequality in treatment by age group that should be addressed as the service progresses.

Much of the work started by the cardiac nurses is now reflected in the National Service Framework performance indicators and standards and is being adopted as standard practice within GP surgeries. All surgeries who employ a cardiac nurse now have CHD registers and processes to ensure that all patients have an annual review that is undertaken either by the cardiac nurse or practice nurse.

Working with members of primary care groups and cardiologists, the Healthy Heart Service has been involved with producing guidelines for the management of CHD patients within the community setting. This has improved links between primary and secondary care providers and it is hoped will ensure the consistency of the provision of high quality service for all CHD patients in St Helens and Knowsley.

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