Cost effectiveness of nurse led secondary prevention clinics for coron
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《英国医生杂志》
1 Health Economics Facility, Health Services Management Centre, University of Birmingham, Birmingham B15 2RT, 2 Department of General Practice and Primary Care, University of Aberdeen, Foresterhill Health Centre, Aberdeen AB25 2AY
Correspondence to: J P Raftery j.p.raftery@bham.ac.uk
Implementation of secondary coronary prevention in primary care is now widely advocated. Several lifestyle measures (smoking cessation, healthy diets, exercise) and medical treatments (antiplatelet agents, blood pressure lowering, lipid lowering, blockade, angiotensin converting enzyme inhibitors) can reduce the risk of coronary events and death in patients with established coronary disease.1 In the United Kingdom, general practitioners will be rewarded financially for achieving certain target standards.2 The problem remains, however, of putting these measures into practice.
Several mechanisms to improve secondary prevention have been evaluated, of which the most successful to date has been nurse led secondary prevention clinics.3-5 Between 1994 and 1995, we undertook one of the randomised trials of nurse led clinics and found them to improve implementation of secondary prevention and health related quality of life at one year.6 7 We followed up the participants after four years and found that the improvements in secondary prevention had translated into reduced total mortality.4 Running clinics, however, uses resources in primary care, especially nurses' time. The clinics incur further costs owing to the increased prescribing of secondary preventive drugs.6 7 When compared with other strategies to improve secondary prevention, such as audit and feedback and opportunistic screening, general practitioners may view nurse led secondary prevention clinics as expensive and be reluctant to incur the costs unless they know that the clinics are cost effective.
Previous studies have evaluated the cost effectiveness of primary prevention clinics and found them to be relatively expensive in terms of cost per life year gained.8 We assessed the costs and cost effectiveness of nurse led secondary prevention clinics, as practised in our previous randomised trial. Alternative interventions we assess are based on that trial. The outcomes in the trial justified the cost effectiveness analysis in terms of cost per life year. We also present cost utility estimates—cost per quality adjusted life year (QALY). The time frame for our study was 4.7 years, the mean duration of patient follow up.
Methods
Nurse led clinics for the secondary prevention of coronary heart disease in primary care are relatively cost effective compared with the threshold of ￡30 000 perceived by NICE.16 The intervention group gained a mean 0.110 life years and 0.124 QALYs compared with the control group. The incremental cost per life year saved was ￡1236 and that per QALY was ￡1097.
The findings of our original randomised trial that secondary prevention in terms of processes of care and prescribing is improved, accord with those of a systematic review of 12 randomised controlled trials of programmes for the management of chronic coronary heart disease.3 We showed that these benefits translated into reductions in total mortality in the medium term.4 The present study shows that the cost per life year gained, quality adjusted or otherwise, is less than ￡1500. The key difference reported was the increased ￡136 cost of the intervention to primary care, owing to attendances at the secondary prevention clinics and increased prescribing.
Although our evaluation was based on a well conducted randomised controlled trial we must consider limitations.17 Firstly, just over half the control group attended at least one secondary prevention clinic after the initial study year.4 Rather than compare secondary prevention clinics with unchanged usual care, we effectively evaluated the costs and benefits of having more patients attend secondary prevention clinics for longer. The total costs of running clinics to primary care (costs of the clinic and additional prescribing) will be higher than the cost difference between control and intervention groups in our study, as we used an intention to treat analysis, despite many patients in the control arm receiving the intervention in the period after the trial. Our estimates of cost effectiveness remain valid, however, as the benefits we found will also have been reduced by this cross over. The increase in both benefits and cost in practice depends on the pre-existing level of use of cardiovascular drugs, particularly statins, in the control group. Some of our data were incomplete, particularly attendances as hospital outpatients, but these had relatively little effect on overall costs to society—our data on high cost activities (for example, hospital admissions) and important outcomes, such as mortality, were almost complete. Where we made assumptions, such as for duration of appointments, we tended to overestimate the cost of the intervention.
Similarly, we ignored benefits if there were doubts that they could be attributable to the intervention, such as hospital admissions for non-cardiovascular conditions. We studied a random sample of general practices and patients, with good recruitment rates for both, so our sample should be representative of general practice at that time. We acknowledge, however, that changes may have occurred in practice since the study began in 1995. The uptake that we reported for some secondary preventive drugs, especially statins, was lower than is likely in the current climate of national standards and incentives for general practitioners. Nevertheless, we found that the clinics improved uptake of secondary prevention by similar absolute amounts whatever the baseline levels, even for high uptake of activities at baseline such as blood pressure management and in practices with higher baseline levels of secondary prevention.6 7 Newly recommended interventions, such as smoking cessation clinics and bupropion, may improve secondary prevention further but are unlikely to alter greatly the cost effectiveness as these changes are likely themselves to be highly cost effective.18
Our study is the first to examine the cost effectiveness of secondary prevention clinics in primary care. The most closely related cost effectiveness study, conducted in general practices in Belfast, was of personal health education to people with angina.19 An important difference is that in Belfast the intervention did not promote secondary preventive drug treatment, and drug costs were in fact reduced. Our findings, with increased drug costs, are more consistent with current recommendations and practice on secondary prevention and, indeed, provide a plausible explanation for the observed reduction in mortality.17 Despite this difference, the findings in Belfast were similar to ours: benefits to total mortality and health related quality of life were reported without a statistically significant extra cost in terms of total NHS resources. Clearly, whether or not the overall costs to society are statistically significant, practitioners in primary care are still faced with the real costs of providing the intervention, so we have gone further by calculating cost effectiveness on the basis of costs to primary care.
Other studies have evaluated the cost effectiveness of primary prevention clinics in primary care.8 20 21 These analyses were limited because, firstly, benefits were slight and measured in terms of risk factors (so benefits to mortality had to be imputed) and, secondly, data on costs and savings to the health service were incomplete. Despite these limitations, some comparisons can be made: the running costs for clinics per patient are reasonably consistent across the trials; running costs for a practice population would, however, be much higher for primary prevention clinics because the target population would be much larger; the estimated cost effectiveness is much better for secondary prevention (￡1236 per life year gained) than for primary prevention (around ￡30 000 per life year gained).
Compared with the wider range of health interventions, the cost effectiveness of secondary prevention clinics remains highly favourable. For example, interventions recommended by NICE have had a cost per QALY as high as ￡39 000.16 The incremental cost per QALY of under ￡1000 that we found was due to the relatively small increase in cost per patient of ￡136, mainly due to modest increases in drug use, even the relatively costly statins. This pattern, however, is consistent with other complex health service interventions, where incremental improvements in process outcomes are more likely to be achieved than wholesale changes.3 None the less, these relatively low increases in cost were linked to health gains that were considerable in terms of deaths, life years, and QALYs.
What is already known on this topic
Nurse led clinics for the secondary prevention of coronary heart disease improve implementation of secondary prevention and reduce mortality
Clinics require primary care resources and to increase prescribing
General practitioners may be unwilling to implement clinics unless they are shown to be cost effective
What this study adds
Nurse led secondary prevention clinics for coronary heart disease resulted in 28 fewer deaths and an increased cost to primary care of ￡136 per patient over four years
The gain in mean life years per patient was 0.110 and the gain in QALYs was 0.124 at an incremental cost of ￡1236 and ￡1097, respectively
Nurse led clinics for the secondary prevention of coronary heart disease in primary care seem to be cost effective compared with most interventions in health care
Contributors: JPR, PM, NCC, and LDR designed the study. PM and NCC collected the data. JPR, GLY, PM, and NCC analysed the data. JPR, GLY, PM, NCC, and LDR wrote the paper. JPR is guarantor.
Funding: The original trial and four year follow up study was funded by the Chief Scientist Office of the Scottish Executive. All researchers are independent of the Chief Scientist Office of the Scottish Executive.
Competing interests: None declared.
Ethical approval: The original trial and follow up study was approved by the Grampian research ethics committee.
References
Guideline 41. Secondary prevention of coronary heart disease following myocardial infarction. Edinburgh: Scottish Intercollegiate Guideline Network, 2000.
BMA/NHS Confederation. New GMS contract. www.bma.org.uk/ap.nsf/Content/NewGMSContract (accessed 22 Jun 2004).
McAlister FA, Lawson FME, Teo KK, Armstrong PW. Randomised trials of secondary prevention programmes in coronary heart disease: systematic review. BMJ 2001;323: 957-62.
Murchie P, Campbell NC, Ritchie LD, Simpson JA, Thain J. Nurse led clinics for the secondary prevention of coronary heart disease: four year follow up of a randomised trial in primary care. BMJ 2003;326: 84-7.
Moher M, Yudkin P, Wright L, Turner R, Fuller A, Schofield T, et al. Cluster randomised controlled trial to compare three methods of promoting secondary prevention of coronary heart disease in primary care. BMJ 2001;322: 1338-42.
Campbell NC, Thain J, Deans HG, Ritchie LD, Rawles JM, Squair JL. Secondary prevention clinics for coronary heart disease: randomised trial of effect on health. BMJ 1998;316: 1434-7.
Campbell NC, Ritchie LD, Thain J, Deans HG, Rawles JM, Squair JL. Secondary prevention in coronary heart disease: a randomised trial of nurse-led clinics in primary care. Heart 1998;80: 447-52.
Wonderling D, McDermott C, Buxton M, Kinmonth A-L, Pike S, Thompson S, et al. Costs and cost effectiveness of cardiovascular screening and intervention: the British family heart study. BMJ 1996;312: 1269-73.
Ware JE. SF-36 health survey-manual and interpretation guide. Boston: Nimrod, 1993.
National Institute for Clinical Excellence. Guide to the methods of technology appraisal. London: NICE, Apr 2004. www.nice.org.uk/page.aspx?o=201974 (reference 0515).
Brazier J, Roberts J, Deverill M. The estimation of a preference-based measure of health from the SF-36. J Health Econ 2002;21: 271-92.
Netten A, Curtis J. Unit costs of health and social care. Canterbury: Personal Social Services Research Unit, University of Kent, 2000.
Scottish drug tariff. Edinburgh: Scottish Executive Health Department, NHS in Scotland, 1998.
Scottish health service costs. Edinburgh: Information and Statistics Division, NHS in Scotland, 1999.
Polsky D, Glick HA, Wilke R, Schulman K. Confidence intervals for cost effectiveness ratios: a comparison of four methods. Health Econ 1997;6: 243-52.
Raftery J. NICE: faster access to modern treatments? Analysis of guidance on health technologies BMJ 2001;323: 1300-3.
Lancaster T. The benefits of nurse led secondary prevention clinics continued after 4 years. Evid Based Med 2003;8: 158.
National Institute for Clinical Excellence. Guidance on the use of nicotine replacement therapy (NRT) and bupropion for smoking cessation. Technology Appraisal Guidance No 39. London: NICE, 2002.
O'Neill C, Normand C, Cupples M, McKnight ME. Cost effectiveness of personal health education in primary care for people with angina in the greater Belfast area of Northern Ireland. J Epidemiol Community Health 1996;50: 538-40.
Langham S, Thorogood M, Normand C, Muir J, Jones L, Fowler G. Costs and cost effectiveness of health checks conducted by nurses in primary care: the Oxcheck study. BMJ 1996;312: 1265-8.
Wonderling D, Langham S, Buxton M, Normand C, McDermott C. What can be concluded from the Oxcheck and British family heart studies: commentary on cost effectiveness analysis. BMJ 1996;312: 1274-8.
((James P Raftery, professor1, Guiqing L Y)
Correspondence to: J P Raftery j.p.raftery@bham.ac.uk
Implementation of secondary coronary prevention in primary care is now widely advocated. Several lifestyle measures (smoking cessation, healthy diets, exercise) and medical treatments (antiplatelet agents, blood pressure lowering, lipid lowering, blockade, angiotensin converting enzyme inhibitors) can reduce the risk of coronary events and death in patients with established coronary disease.1 In the United Kingdom, general practitioners will be rewarded financially for achieving certain target standards.2 The problem remains, however, of putting these measures into practice.
Several mechanisms to improve secondary prevention have been evaluated, of which the most successful to date has been nurse led secondary prevention clinics.3-5 Between 1994 and 1995, we undertook one of the randomised trials of nurse led clinics and found them to improve implementation of secondary prevention and health related quality of life at one year.6 7 We followed up the participants after four years and found that the improvements in secondary prevention had translated into reduced total mortality.4 Running clinics, however, uses resources in primary care, especially nurses' time. The clinics incur further costs owing to the increased prescribing of secondary preventive drugs.6 7 When compared with other strategies to improve secondary prevention, such as audit and feedback and opportunistic screening, general practitioners may view nurse led secondary prevention clinics as expensive and be reluctant to incur the costs unless they know that the clinics are cost effective.
Previous studies have evaluated the cost effectiveness of primary prevention clinics and found them to be relatively expensive in terms of cost per life year gained.8 We assessed the costs and cost effectiveness of nurse led secondary prevention clinics, as practised in our previous randomised trial. Alternative interventions we assess are based on that trial. The outcomes in the trial justified the cost effectiveness analysis in terms of cost per life year. We also present cost utility estimates—cost per quality adjusted life year (QALY). The time frame for our study was 4.7 years, the mean duration of patient follow up.
Methods
Nurse led clinics for the secondary prevention of coronary heart disease in primary care are relatively cost effective compared with the threshold of ￡30 000 perceived by NICE.16 The intervention group gained a mean 0.110 life years and 0.124 QALYs compared with the control group. The incremental cost per life year saved was ￡1236 and that per QALY was ￡1097.
The findings of our original randomised trial that secondary prevention in terms of processes of care and prescribing is improved, accord with those of a systematic review of 12 randomised controlled trials of programmes for the management of chronic coronary heart disease.3 We showed that these benefits translated into reductions in total mortality in the medium term.4 The present study shows that the cost per life year gained, quality adjusted or otherwise, is less than ￡1500. The key difference reported was the increased ￡136 cost of the intervention to primary care, owing to attendances at the secondary prevention clinics and increased prescribing.
Although our evaluation was based on a well conducted randomised controlled trial we must consider limitations.17 Firstly, just over half the control group attended at least one secondary prevention clinic after the initial study year.4 Rather than compare secondary prevention clinics with unchanged usual care, we effectively evaluated the costs and benefits of having more patients attend secondary prevention clinics for longer. The total costs of running clinics to primary care (costs of the clinic and additional prescribing) will be higher than the cost difference between control and intervention groups in our study, as we used an intention to treat analysis, despite many patients in the control arm receiving the intervention in the period after the trial. Our estimates of cost effectiveness remain valid, however, as the benefits we found will also have been reduced by this cross over. The increase in both benefits and cost in practice depends on the pre-existing level of use of cardiovascular drugs, particularly statins, in the control group. Some of our data were incomplete, particularly attendances as hospital outpatients, but these had relatively little effect on overall costs to society—our data on high cost activities (for example, hospital admissions) and important outcomes, such as mortality, were almost complete. Where we made assumptions, such as for duration of appointments, we tended to overestimate the cost of the intervention.
Similarly, we ignored benefits if there were doubts that they could be attributable to the intervention, such as hospital admissions for non-cardiovascular conditions. We studied a random sample of general practices and patients, with good recruitment rates for both, so our sample should be representative of general practice at that time. We acknowledge, however, that changes may have occurred in practice since the study began in 1995. The uptake that we reported for some secondary preventive drugs, especially statins, was lower than is likely in the current climate of national standards and incentives for general practitioners. Nevertheless, we found that the clinics improved uptake of secondary prevention by similar absolute amounts whatever the baseline levels, even for high uptake of activities at baseline such as blood pressure management and in practices with higher baseline levels of secondary prevention.6 7 Newly recommended interventions, such as smoking cessation clinics and bupropion, may improve secondary prevention further but are unlikely to alter greatly the cost effectiveness as these changes are likely themselves to be highly cost effective.18
Our study is the first to examine the cost effectiveness of secondary prevention clinics in primary care. The most closely related cost effectiveness study, conducted in general practices in Belfast, was of personal health education to people with angina.19 An important difference is that in Belfast the intervention did not promote secondary preventive drug treatment, and drug costs were in fact reduced. Our findings, with increased drug costs, are more consistent with current recommendations and practice on secondary prevention and, indeed, provide a plausible explanation for the observed reduction in mortality.17 Despite this difference, the findings in Belfast were similar to ours: benefits to total mortality and health related quality of life were reported without a statistically significant extra cost in terms of total NHS resources. Clearly, whether or not the overall costs to society are statistically significant, practitioners in primary care are still faced with the real costs of providing the intervention, so we have gone further by calculating cost effectiveness on the basis of costs to primary care.
Other studies have evaluated the cost effectiveness of primary prevention clinics in primary care.8 20 21 These analyses were limited because, firstly, benefits were slight and measured in terms of risk factors (so benefits to mortality had to be imputed) and, secondly, data on costs and savings to the health service were incomplete. Despite these limitations, some comparisons can be made: the running costs for clinics per patient are reasonably consistent across the trials; running costs for a practice population would, however, be much higher for primary prevention clinics because the target population would be much larger; the estimated cost effectiveness is much better for secondary prevention (￡1236 per life year gained) than for primary prevention (around ￡30 000 per life year gained).
Compared with the wider range of health interventions, the cost effectiveness of secondary prevention clinics remains highly favourable. For example, interventions recommended by NICE have had a cost per QALY as high as ￡39 000.16 The incremental cost per QALY of under ￡1000 that we found was due to the relatively small increase in cost per patient of ￡136, mainly due to modest increases in drug use, even the relatively costly statins. This pattern, however, is consistent with other complex health service interventions, where incremental improvements in process outcomes are more likely to be achieved than wholesale changes.3 None the less, these relatively low increases in cost were linked to health gains that were considerable in terms of deaths, life years, and QALYs.
What is already known on this topic
Nurse led clinics for the secondary prevention of coronary heart disease improve implementation of secondary prevention and reduce mortality
Clinics require primary care resources and to increase prescribing
General practitioners may be unwilling to implement clinics unless they are shown to be cost effective
What this study adds
Nurse led secondary prevention clinics for coronary heart disease resulted in 28 fewer deaths and an increased cost to primary care of ￡136 per patient over four years
The gain in mean life years per patient was 0.110 and the gain in QALYs was 0.124 at an incremental cost of ￡1236 and ￡1097, respectively
Nurse led clinics for the secondary prevention of coronary heart disease in primary care seem to be cost effective compared with most interventions in health care
Contributors: JPR, PM, NCC, and LDR designed the study. PM and NCC collected the data. JPR, GLY, PM, and NCC analysed the data. JPR, GLY, PM, NCC, and LDR wrote the paper. JPR is guarantor.
Funding: The original trial and four year follow up study was funded by the Chief Scientist Office of the Scottish Executive. All researchers are independent of the Chief Scientist Office of the Scottish Executive.
Competing interests: None declared.
Ethical approval: The original trial and follow up study was approved by the Grampian research ethics committee.
References
Guideline 41. Secondary prevention of coronary heart disease following myocardial infarction. Edinburgh: Scottish Intercollegiate Guideline Network, 2000.
BMA/NHS Confederation. New GMS contract. www.bma.org.uk/ap.nsf/Content/NewGMSContract (accessed 22 Jun 2004).
McAlister FA, Lawson FME, Teo KK, Armstrong PW. Randomised trials of secondary prevention programmes in coronary heart disease: systematic review. BMJ 2001;323: 957-62.
Murchie P, Campbell NC, Ritchie LD, Simpson JA, Thain J. Nurse led clinics for the secondary prevention of coronary heart disease: four year follow up of a randomised trial in primary care. BMJ 2003;326: 84-7.
Moher M, Yudkin P, Wright L, Turner R, Fuller A, Schofield T, et al. Cluster randomised controlled trial to compare three methods of promoting secondary prevention of coronary heart disease in primary care. BMJ 2001;322: 1338-42.
Campbell NC, Thain J, Deans HG, Ritchie LD, Rawles JM, Squair JL. Secondary prevention clinics for coronary heart disease: randomised trial of effect on health. BMJ 1998;316: 1434-7.
Campbell NC, Ritchie LD, Thain J, Deans HG, Rawles JM, Squair JL. Secondary prevention in coronary heart disease: a randomised trial of nurse-led clinics in primary care. Heart 1998;80: 447-52.
Wonderling D, McDermott C, Buxton M, Kinmonth A-L, Pike S, Thompson S, et al. Costs and cost effectiveness of cardiovascular screening and intervention: the British family heart study. BMJ 1996;312: 1269-73.
Ware JE. SF-36 health survey-manual and interpretation guide. Boston: Nimrod, 1993.
National Institute for Clinical Excellence. Guide to the methods of technology appraisal. London: NICE, Apr 2004. www.nice.org.uk/page.aspx?o=201974 (reference 0515).
Brazier J, Roberts J, Deverill M. The estimation of a preference-based measure of health from the SF-36. J Health Econ 2002;21: 271-92.
Netten A, Curtis J. Unit costs of health and social care. Canterbury: Personal Social Services Research Unit, University of Kent, 2000.
Scottish drug tariff. Edinburgh: Scottish Executive Health Department, NHS in Scotland, 1998.
Scottish health service costs. Edinburgh: Information and Statistics Division, NHS in Scotland, 1999.
Polsky D, Glick HA, Wilke R, Schulman K. Confidence intervals for cost effectiveness ratios: a comparison of four methods. Health Econ 1997;6: 243-52.
Raftery J. NICE: faster access to modern treatments? Analysis of guidance on health technologies BMJ 2001;323: 1300-3.
Lancaster T. The benefits of nurse led secondary prevention clinics continued after 4 years. Evid Based Med 2003;8: 158.
National Institute for Clinical Excellence. Guidance on the use of nicotine replacement therapy (NRT) and bupropion for smoking cessation. Technology Appraisal Guidance No 39. London: NICE, 2002.
O'Neill C, Normand C, Cupples M, McKnight ME. Cost effectiveness of personal health education in primary care for people with angina in the greater Belfast area of Northern Ireland. J Epidemiol Community Health 1996;50: 538-40.
Langham S, Thorogood M, Normand C, Muir J, Jones L, Fowler G. Costs and cost effectiveness of health checks conducted by nurses in primary care: the Oxcheck study. BMJ 1996;312: 1265-8.
Wonderling D, Langham S, Buxton M, Normand C, McDermott C. What can be concluded from the Oxcheck and British family heart studies: commentary on cost effectiveness analysis. BMJ 1996;312: 1274-8.
((James P Raftery, professor1, Guiqing L Y)