Prescribing of lipid regulating drugs and admissions for myocardial infarction in England
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《英国医生杂志》
Despite declining death rates in recent decades, coronary heart disease remains one of the leading causes of death in England.w1 Statins have been shown to reduce the risk of death and acute myocardial infarction in people who have coronary heart disease or are at high risk of developing it.w2-w4 A key objective of the national service framework for coronary heart disease is to increase the uptake of statins in these two groups. We conducted an analysis of primary care prescribing of lipid regulating drugs and admission rates for acute myocardial infarction in the NHS for 1996-2002.
The bottom line
? Large increases in the cost and volume of prescribing of lipid regulating drugs have been associated with only a modest decline in standardised admission ratios for acute myocardial infarction
We examined NHS primary care prescribing and hospital admissions data for acute myocardial infarction in England from 1996-7 to 2002-3. The national prescribing data came from the Department of Health, which collates information on all prescriptions dispensed in the community. The number of prescribed items for primary care trusts came from the PACT system, which collates information on prescriptions issued by general practitioners.w5 Data on admissions came from the hospital episode statistics system. To avoid double counting of diagnoses, we used admissions rather than consultant episodes as the numerator in the calculation of annual standardised admission ratios.
We found that prescriptions of lipid regulating drugs (largely statins) increased from 3.1m to 17.6m items during 1996-2002, a total cost to the NHS of ￡571m in 2002 compared with ￡93m in 1996. The standardised admission ratio for acute myocardial infarction fell from the baseline of 100.0 in 1996-7 to 90.7 in 2001-2 before increasing to 95.8 in 2002-3 (fig 1).
Primary care trusts showed a fourfold variation in prescribing of lipid regulating agents in 2002, from 180 to 730 items per 1000 patients. Standardised admission ratios for acute myocardial infarction also varied about fourfold, from 38 to 181. There was an association between prescription rates and standardised admission ratios (correlation coefficient 0.43, P < 0.001; fig 2). This association may exist because admission rates for myocardial infarction might reflect the prevalence of coronary heart disease in the local population.
Our results indicate that a large increase in the cost and volume of the prescribing of lipid regulating drugs has been associated with only a modest reduction in admission rates for myocardial infarction. During the study period, statins were recommended for high risk patients, but many myocardial infarctions occur in people at low risk who would not have been recommended for treatment with statins. This would limit the population impact of the increase in the prescribing of statins.
The increase in admissions for myocardial infarctions in the final year of analysis may be due to changing diagnostic criteria, including the use of cardiac troponin measurements and recognition of the concept of acute coronary syndrome and non-ST elevation myocardial infarction (NSTEMI).w6 At primary care trust level, there are large variations in prescribing and admission rates, which needs further investigation. Myocardial infarction has a multifactorial aetiology, and the message about the use of statins needs to go hand in hand with the management of other risk factors such as smoking, hypertension, and diabetes.
Dr Foster's case notes was compiled by Azeem Majeed, Paul Aylin, Susan Williams, Alex Bottle, and Brian Jarman at the Dr Foster Unit at Imperial College. Dr Foster is an independent research and publishing organisation created to examine measures of clinical performance.
References and full methodological details are on bmj.com and drfoster.com(Azeem Majeed, Paul Aylin,)
The bottom line
? Large increases in the cost and volume of prescribing of lipid regulating drugs have been associated with only a modest decline in standardised admission ratios for acute myocardial infarction
We examined NHS primary care prescribing and hospital admissions data for acute myocardial infarction in England from 1996-7 to 2002-3. The national prescribing data came from the Department of Health, which collates information on all prescriptions dispensed in the community. The number of prescribed items for primary care trusts came from the PACT system, which collates information on prescriptions issued by general practitioners.w5 Data on admissions came from the hospital episode statistics system. To avoid double counting of diagnoses, we used admissions rather than consultant episodes as the numerator in the calculation of annual standardised admission ratios.
We found that prescriptions of lipid regulating drugs (largely statins) increased from 3.1m to 17.6m items during 1996-2002, a total cost to the NHS of ￡571m in 2002 compared with ￡93m in 1996. The standardised admission ratio for acute myocardial infarction fell from the baseline of 100.0 in 1996-7 to 90.7 in 2001-2 before increasing to 95.8 in 2002-3 (fig 1).
Primary care trusts showed a fourfold variation in prescribing of lipid regulating agents in 2002, from 180 to 730 items per 1000 patients. Standardised admission ratios for acute myocardial infarction also varied about fourfold, from 38 to 181. There was an association between prescription rates and standardised admission ratios (correlation coefficient 0.43, P < 0.001; fig 2). This association may exist because admission rates for myocardial infarction might reflect the prevalence of coronary heart disease in the local population.
Our results indicate that a large increase in the cost and volume of the prescribing of lipid regulating drugs has been associated with only a modest reduction in admission rates for myocardial infarction. During the study period, statins were recommended for high risk patients, but many myocardial infarctions occur in people at low risk who would not have been recommended for treatment with statins. This would limit the population impact of the increase in the prescribing of statins.
The increase in admissions for myocardial infarctions in the final year of analysis may be due to changing diagnostic criteria, including the use of cardiac troponin measurements and recognition of the concept of acute coronary syndrome and non-ST elevation myocardial infarction (NSTEMI).w6 At primary care trust level, there are large variations in prescribing and admission rates, which needs further investigation. Myocardial infarction has a multifactorial aetiology, and the message about the use of statins needs to go hand in hand with the management of other risk factors such as smoking, hypertension, and diabetes.
Dr Foster's case notes was compiled by Azeem Majeed, Paul Aylin, Susan Williams, Alex Bottle, and Brian Jarman at the Dr Foster Unit at Imperial College. Dr Foster is an independent research and publishing organisation created to examine measures of clinical performance.
References and full methodological details are on bmj.com and drfoster.com(Azeem Majeed, Paul Aylin,)