Management of ischaemic heart disease in primary care: towards better practice

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1 Journal of Public Health Medicine Vol. 21, No. 2, pp Printed in Great Britain Management of ischaemic heart disease in primary care: towards better practice Krish Thiru, Jeremy Gray and Azeem Majeed on behalf of STaRNet Abstract Background Ischaemic heart disease is the commonest cause of mortality in the United Kingdom. The objective of this study was to assess the management of patients with ischaemic heart disease in primary care, focusing particularly on the management of hypercholesterolaemia. Methods A cross-sectional survey was carried out of the clinical records of patients aged years with confirmed ischaemic heart disease in six general practices (total list size ). Results Recording of risk factors varied from 97 per cent for blood pressure to 73 per cent for cholesterol measurement. Seventy-two per cent of the patients had adequate blood pressure control, based on their last recorded blood pressure. Sixty-one per cent (267) were known to be taking aspirin daily and 29 per cent (125) had undergone revascularization treatment. Sixty-eight per cent (296) of the patients had pre-treatment cholesterol levels of 5.5 mmol/l or greater and 34 per cent (147) were currently taking lipid lowering drugs. Statins were the most commonly used cholesterol lowering agents and were being taken by 30 per cent (131) of the patients. Patients who had undergone revascularization treatment had levels of recording of risk factors similar to other patients with ischaemic heart disease but were more likely to be taking daily aspirin (71 per cent versus 57 per cent, relative risk 1.24, 95 per cent confidence intervals (CI) ). The mean pre-treatment cholesterol was 6.49 mmol/l and the mean post-treatment cholesterol 5.80 mmol/l (difference 0.69 mmol/l, 95 per cent CI mmol/l). Conclusions Systematic searches of computerized and paper medical records can identify subgroups of patients who will benefit from continuing follow-up in primary care. The results of this study suggest that ischaemic heart disease remains an area where there is scope to improve the management of patients in primary care. Considerable effort will be required from the members of the primary health care team to achieve this objective, particularly in the areas of computerized data collection and in the identification and recall of patients. Keywords: primary care, ischaemic heart disease, cholesterol, statins, clinical data recording Introduction Ischaemic heart disease is the single commonest cause of death in the United Kingdom. 1 It is also a major cause of morbidity and is responsible for a significant proportion of the NHS budget. There are now several treatments available that are known to reduce the risk of death and of major cardiac events, such as myocardial infarction, in patients with ischaemic heart disease. Interventions of established effectiveness include the cessation of smoking, 2 the use of aspirin, 3 and the use of cholesterol-lowering drugs. 4 However, the uptake of effective interventions by at-risk groups of patients remains relatively low. 5 7 Furthermore, although general practitioners (GPs) now have numerous guidelines on the management of ischaemic heart disease, many practical problems remain in trying to implement the recommendations of these guidelines in primary care. 8,9 In 1996, the Research & Development Directorate of the South Thames Regional NHS Office agreed to fund a network of research and development general practices across the South Thames Region (STaRNet). Fifteen practices were recruited through a competitive process. One of the two main objectives of the network was to improve the uptake of evidence-based medicine in primary care (the other was to expand the research base in primary care). Four guidelines were selected in which to pilot the expansion of evidence-based medicine in primary care. Practices in STaRNet were asked to choose one of these four areas, of which one was the management of ischaemic heart disease with a specific focus on the management of hypercholesterolaemia. This was done because prescribing of statins has increased substantially in recent years and there is great variation between practices in the use of this class of drugs. 10 Six of the 15 practices in the research network elected to participate in this project. General practitioners and practice nurses from the six practices met several times to agree on the objectives of the project. They agreed that a number of preliminary steps were required before the current provision of care for patients with 1 Department of General Practice and Primary Care, St George s Hospital Medical School, Cranmer Terrace, London SW17 0RE. 2 Lavender Hill Group Practice, 19 Pountney Road, London SW11 5TU. Krish Thiru, Research Assistant 1 Jeremy Gray, General Practitioner 2 Azeem Majeed, Senior Lecturer in General Practice 1 Address correspondence to Mr K. Thiru. Faculty of Public Health Medicine 1999

2 180 JOURNAL OF PUBLIC HEALTH MEDICINE ischaemic heart disease in these practices could be audited. The most important of these was to construct a disease register and to agree on what information needed to be recorded on the practices computers. Once these preliminary steps had been carried out, the computerized and paper medical records of existing and future patients with ischaemic heart disease would be flagged to ensure that details of risk factors and investigations were recorded, and that patients were offered appropriate treatment. In this paper, we describe the process of identifying patients with ischaemic heart disease in the six practices and the steps that were taken to improve the management of these patients, including the recording of clinical information on practice computers. Methods Each practice identified patients with ischaemic heart disease through disease registers and through computerized repeat prescribing records. Patients identified through this process had their paper records checked to confirm that they had definite ischaemic heart disease. This was defined using objective measures: either confirmed myocardial infarction, a resting or exercise electrocardiograph showing ischaemic changes, evidence of cardiac ischaemia on thallium scanning, or an angiogram showing coronary atheroma. Patients who did not have definite ischaemic heart disease were excluded from further analysis. This would have included some patients in whom the GP suspected ischaemic heart disease but in whom the diagnosis had not been confirmed, for example, patients awaiting further investigation. Patients aged 75 years or over were also excluded because of the lack of knowledge of the effects of cholesterol lowering therapy in this agegroup. Patients paper and computerized medical records were then searched for information on recording of risk factors, co-morbidity, investigations and treatment (Table 1). Combined results for all six practices are presented in this paper. After data had been collected and analysed, GPs and practice nurses met again to discuss the implications of the findings and to agree recommendations for future practice. Table 1 Information collected on patients with confirmed ischaemic heart disease Demographic information Smoking status Family history Body mass index Blood pressure Initial cholesterol level Latest cholesterol level Treatment with aspirin Past history of revascularization treatment Health promotion advice Treatment with lipid lowering drugs Co-morbidity Table 2 Characteristics of the six practices that took part in this study Practice Number of partners List size Location A Twickenham B Folkestone C Thamesmead D Guildford E Battersea F Crawley Results Practice characteristics The characteristics of the six practices that took part in the study are shown in Table 2. Their total list size was and they were located in a variety of environments ranging from inner London to the south coast of England. Hence, the practices lists included patients from areas of socio-economic deprivation as well as more affluent areas. Recording of risk factors A total of 435 patients with established ischaemic heart disease were identified, giving a prevalence in the year old age group of 121 per (Table 3). Recording of risk factors varied from 97 per cent for blood pressure to 73 per cent for the post-treatment cholesterol measurement (the post-treatment cholesterol measurement was defined as the last measurement taken after advice on cholesterol status and diet had been given). The distribution of blood pressure control, body mass index, cigarette smoking and blood cholesterol are shown in Table 4. Twenty-five per cent (109) of the patients had inadequate blood pressure control, based on their last recorded blood pressure. Of the 435 patients, 61 per cent (267) were known to be taking aspirin daily and 29 per cent (125) had undergone revascularization treatment (coronary artery bypass grafting or angioplasty). Table 3 Prevalence of confirmed ischaemic heart disease Age group Number Rate per (years) of cases Population

3 MANAGEMENT OF ISCHAEMIC HEART DISEASE 181 Table 4 Recording of risk factors in medical records or on practice computer (percentages, with numbers given in parentheses) Treatment of raised cholesterol All patients Smoking status 92 (399) 90 (113) Current smoker 22 (95) 18 (23) Ex-smoker 39 (171) 40 (50) Non-smoker 31 (133) 32 (40) Not recorded 8 (36) 10 (12) Body mass index (kg/m 2 ) 83 (361) 82 (102) < (131) 30 (38) (129) 30 (38) (94) 20 (20) 40 2 (7) 2 (2) Not recorded 17 (74) 18 (23) Blood pressure (mmhg) 97 (424) 97 (121) Normal 72 (315) 75 (94) Systolic > (68) 13 (16) Diastolic > 90 3 (12) 5 (6) Systolic > 150 and diastolic > 90 7 (29) 4 (5) Not recorded 3 (11) 3 (4) Pre-treatment cholesterol (mmol/l) 76 (329) 78 (98) < (33) 6 (8) (39) 6 (8) (72) 18 (22) (141) 36 (45) (44) 12 (15) Not recorded 24 (106) 22 (27) Post-treatment cholesterol (mmol/l) 73 (318) 76 (95) < (49) 11 (14) (83) 17 (21) (76) 18 (22) (96) 26 (33) (14) 4 (5) Not recorded 27 (117) 24 (30) Patients with previous revascularization treatment A total of 68 per cent (296) patients had pre-treatment cholesterol levels of 5.5 mmol/l or greater and 34 per cent (147) were currently taking lipid lowering drugs. Of the patients who had undergone cholesterol testing, 136 (31 per cent) records showed no information on the advice or treatment given after the test. Statins were the most commonly used drug and were prescribed for 30 per cent (131) of the patients. Simvastatin was the most commonly used statin preparation, prescribed for 26 per cent (111) of the patients. Mean blood cholesterol after starting treatment fell from 6.49 to 5.80 mmol/l (difference 0.69, 95 per cent confidence interval (CI) ). However, 43 per cent (186) of patients still had a blood cholesterol measurement of 5.5 mmol/l or more, suggesting that there was further scope for more intensive dietary and drug treatment in these patients. In its most frequently prescribed dosage of 20 mg daily, the cost to the NHS of simvastatin is per month. Hence, in terms of drug costs, to treat all patients in the six practices with established ischaemic heart disease and pre-treatment cholesterol levels of 5.5 mmol/l or more would cost about per year. Treating the 186 patients with current cholesterol levels of 5.5 mmol/l or more would cost about per year. Subgroup analysis The 125 patients who had undergone revascularization treatment, who would be expected to be the more severe cases of ischaemic heart disease, had similar levels of recording of risk factors as the group of 435 patients as a whole (Table 4). However, they were more likely to be recorded as taking daily aspirin (71 per cent for patients who had undergone revascularization treatment versus 57 per cent for patients who had not undergone treatment, relative risk 1.24, 95 per cent CI ) and were also younger (mean age 64.2 years versus 68.8 years). Eighty-two patients who had undergone revascularization treatment had blood cholesterol levels of 5.5 mmol/l or greater; 49 (60 per cent) of these patients were on lipid lowering agents. The statins were the most commonly used class of drugs and were prescribed for 44 of the 49 patients on lipid lowering agents who had undergone revascularization treatment. Examination of the use of lipid lowering agents in other subgroups did not reveal any significant differences. There were no differences in the use of these drugs between men and women, between smokers and non-smokers, and between people with normal or raised body mass index. Discussion We found that there is still scope for an improvement in primary care in both the recording of clinical information and the management of patients with objective evidence of ischaemic heart disease. In particular, many patients had poorly controlled blood pressure or raised blood cholesterol levels. This was the case even though the six practices that took part in this study were all research and development practices, and hence likely to be providing higher quality of care than the average general practice. Because of the strict inclusion criteria, some patients with ischaemic heart disease would not have been included in this study. Presumably, the recording of risk factors in this group of patients would have been even lower. A survey of patients with ischaemic heart disease in a more typical sample of general practices in the Grampian region of Scotland found even lower levels of recording of risk factors and uptake of potentially effective interventions than in our own study. 11 The benefits of treatment, especially of cholesterol lowering treatment, are now clear and all patients with ischaemic heart disease should have their cholesterol level

4 182 JOURNAL OF PUBLIC HEALTH MEDICINE checked and recorded. The recording of information on nonpharmacological interventions could also be significantly improved. However, improving care in these areas will not be easy and requires substantial commitment from patients, the primary health care team and specialist services. 7,12 Increased resources will also be required to facilitate this process. Recording of clinical information and follow-up of patients by the primary health care team clearly need to be improved. At the same time, however, patients need to be made more aware of their own responsibilities. Anecdotally, many of the GPs who took part in this study reported difficulties in trying to ensure patients attended for follow-up and complied with advice on treatment and lifestyle. Other points that arose from this study were the importance of accurate data collection, done in a way that made the data easily accessible, and the financial implications of more intensive treatment, in particular treatment of raised blood cholesterol with statins. This study did, however, show that practices can work together to reach agreement on issues such as data collection and the implementation of guidelines, areas that will become increasingly important with the formation of primary care groups. 13,14 Recording of information There is now no lack of guidance for GPs on how to manage chronic diseases such as ischaemic heart disease. However, the practical issues behind the implementation of guidelines and their evaluation in general practice have been less well discussed. For example, do minimum data sets need to be agreed so that all practices in a locality can collect useful data on patients with chronic diseases? Although the construction of Table 5 Recommendations on data collection 1 Agree a minimum data set for collection of information of patients with chronic diseases; ideally, the items for inclusion should be agreed with both the locality commissioning group and the local health authority Agree a standardized disease definition to allow construction of disease registers Flag the computerized and paper medical records of patients who are included in the disease registers; this helps ensure that members of the primary health care team will record any significant clinical events in these patients on the practice computer Ensure that all members of the primary health care team are aware of the guidelines on data collection and that they record the information in the minimum data set on the practice computer Keep the data recorded on the practice computer accurate and up to date The practice computer system should allow data to be exported in a standard format so that they can be imported into a statistical package for further analysis Monitor practices performance against agreed standards at least once every year and feed back comparative information to each practice such data sets would be a useful development and sounds straightforward, in practice it would not be an easy task to achieve. General practices would first have to agree the content of the minimum data set. They then would have to agree definitions for each item in the data set and standardized methods of collecting the data. Patients with a disease then have to be identified, which in turn requires the construction of a disease definition and also of a disease register. Data then have to be collected on these patients. Initially, the data will be retrospective and will be collected from case notes. Once the retrospective data collection is complete, prospective data collection needs to be established so as to ensure that the information on these patients is updated and that identification of new cases is possible. Finally, to facilitate analysis, all the information collected has to be recorded on the practice computer system in a format that can be easily extracted and analysed (Tables 5 and 6). All this requires more work from the members of the primary health care team at a time when they are already facing increasing demands on their time. Financial implications of increased prescribing of statins We estimated that treating with statins all patients under 75 years of age in the six practices with confirmed ischaemic heart Table 6 Recommendations on data collection 2 Morbidity A record must be made on the practice computer of any significant morbidity event, including: all events resulting in a hospitalization or referral to any specialist, and the outcome of the referral (diagnosis, procedure, etc.) all significant test results all test results required for long-term monitoring (blood pressure, cholesterol, etc.) all events resulting in the instigation of a new drug or the withdrawal of a drug the patient is already taking possible or query diagnoses should be clearly separated from definite diagnoses Prescriptions A record must be made on the practice computer of all events resulting in the prescription or withdrawal of a drug including: the original indication for treatment the indication for any change or addition to treatment the date of any change in treatment Health interventions A record must be made on the practice computer of any interventions carried out or recommended by a member of the primary health care team; this would include health promotion advice in areas such as smoking, alcohol and diet Smoking status Information on the patient s current smoking status should be recorded every three years; for current non-smokers, precise terms such as never smoked or former smoker should be used in preference to non-smoker

5 MANAGEMENT OF ISCHAEMIC HEART DISEASE 183 disease and a cholesterol level of 5.5 mmol/l or more would cost between and per year. In May 1997, the Standing Medical Advisory Committee published guidelines suggesting that patients with either a past history of myocardial infarction and a cholesterol level of 4.8 mmol/l or more, or a history of angina and a cholesterol level of 5.5 mmol/l or more, should be treated with statins. 15 The committee also suggested that the use of statins should be considered in patients without symptomatic ischaemic heart disease but who had a risk of a major coronary event (defined as a myocardial infarction or death from ischaemic heart disease) of 3 per cent a year or more. Following this guidance would further increase the costs of prescribing statins in general practice. We have not yet been able to quantify the precise costs of the committee s recommendations but hope to do this when we next repeat our study. We also aim to collect information on patients aged 75 years and over when we do this, as this is a group that is often omitted from research into ischaemic heart disease even though they are the group at greatest risk of dying from or suffering a major cardiac event. If treatment with statins was extended to include older patients or patients without ischaemic heart disease but at high risk of suffering a major cardiac event (primary prevention), this would further increase the costs of lipid lowering drugs in primary care. 16 Additional resources would also be required to improve management in areas such as control of raised blood pressure and increasing the uptake of aspirin, especially in practices that are less well developed than those that took part in this study. Every general practice in England is now a member of a primary care group with a single budget for prescribing and other health services costs. Hence, GPs will have to think much more carefully how best to manage conditions such as ischaemic heart disease, which account for a high proportion of total health service costs. 17 Generalizibility of findings The practices that took part in this study included patients from across the South Thames Region. Their lists included patients from deprived areas, areas with high ethnic minority populations, and areas of comparative affluence. Hence, their patients are likely to be representative of the general population even though the practices themselves were larger, better organized, and more computerized than average. However, the prevalence of ischaemic heart disease in the year old age group was lower than that predicted from the fourth national survey of morbidity in general practice. 18 The lower prevalence was probably due to the very strict definition of ischaemic heart disease used in our study, with only patients in whom there was objective evidence of heart disease being included. As discussed above, recording of risk factors and uptake of interventions is likely to be lower in a more general sample of patients with ischaemic heart disease from a representative sample of general practices. Conclusions Ischaemic heart disease remains an area where there is scope to improve the management of patients in primary care. However, to achieve this objective, considerable effort will be required from the members of the primary health care team even in well-organized research and development practices. There will also be major financial implications from the more intensive treatment of ischaemic heart disease in primary care, in particular from the increased use of lipid-lowering drugs such as the statins. In practices that are not as highly organized and computerized as the practices in this study, the workload and financial implications of trying to improve the management of ischaemic heart disease are likely to be even greater. Acknowledgements We thank the staff of the six general practices that took part in this study for their help in collecting the data. We also thank the General Practice Research Database Team at the Office for National Statistics for advice on how to improve the recording of clinical information on general practice computers. STaRNet is funded by the NHS Executive, South Thames Region and is a collaborative project between St George s Hospital Medical School and Guy s, King s and St Thomas Medical School and the two Postgraduate Departments of General Practice in the South Thames Region. Contributors are Ms S. Brew, Dr B. Christie, Dr A. Cooper, Dr D. Goodwin, Dr J. Gray, Dr C. Kroll, Dr A. Majeed, Mrs K. Masters, Dr J. Oxenbury, Mrs J. Sawyer, Mr K. Thiru, Mrs S. Wells, Dr D. Wheeler. References 1 Public health common data set London: Department of Health, Daly LE, Graham IM, Hickey N, et al. Does stopping smoking delay onset of angina after infarction? Br Med J 1985; 291: Antiplatelet Trialists Collaboration. Collaborative overview of randomised trials of antiplatelet therapy. I. Prevention of death, myocardial infarction and stroke by prolonged antiplatelet therapy in various categories of patients. Br Med J 1994; 308: The Scandinavian Simvastatin Survival Study Group. 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