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Use of statins in primary or secondary prevention of coronary heart disease is cost-effective in some but not all
Use of statins in primary or secondary prevention of coronary heart disease is cost-effective in some but not all
Pharoah PDP, Hollingworth W. Cost effectiveness of lowering cholesterol concentration with statins in patients with and without pre-existing coronary heart disease: life-table method applied to a health authority population. BMJ 1996; 312:1443-1448
Objective To determine the cost-effectiveness of lowering serum cholesterol with statins in men and women with varying risk of fatal coronary artery disease.
Design A mathematical model was constructed, based on life-table methodology, that was used to estimate the benefit on survival of treating men and women, aged 45-64 years, with a statin for 10 years.
Setting Population of a typical district health authority in the UK.
Subjects An imaginary cohort of men and women, aged 45-64 years, with and without pre-existing coronary artery disease.
Intervention Estimates for treatment effect were obtained from published randomized clinical trials of primary and secondary prevention in which patients were allocated to either treatment with a statin or control group.
Main cost and outcome measures The cost of treatment with a statin was estimated by determining the direct costs of the drug offset by savings associated with lives saved and reductions in rates of non-fatal myocardial infarctions (MI), coronary angiograms and revascularization
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procedures. The main outcome measure was cost per life year saved.
Main results Five groups of patients, with decreasing risk of fatal coronary artery disease, were defined which would be considered eligible for treatment with a statin for primary or secondary prevention: group 1, men aged 45-64 and women aged 55-64 with previous MI and cholesterol > 5.4 mmol/L; group 2, men aged 45-64 and women aged 55-64 with angina and cholesterol > 5.4 retool/L; group 3, men aged 55-64 with no history of coronary heart disease and cholesterol > 6.5 mmol/L; group 4, women aged 45-54 with angina or previous MI and cholesterol > 5.4 mmol/L; and group 5, men aged 45-54 with no history of coronary heart disease and cholesterol > 6.5 mmol/L. The cost-effectiveness varied greatly between risk groups with a cost per life year saved of £16 000 in the highest risk group and £230 000 in the lowest risk group. Conclusion The cost-effectiveness of treating hypercholesterolemia with statins is dependent on the patient' s risk for coronary artery disease. Treating patients at highest risk is most cost-effective. Treatment of all eligible patients for both primary and secondary prevention would be prohibitively expensive.
EVIDENCE-BASED CARDIOVASCULAR MEDICINE
Commentary A decade of randomized trials has shown that the 'statins' are effective in both the primary and secondary prevention of coronary events. For secondary prevention, statins clearly have a favorable impact on all-cause mortality. A logical question arises: can we afford to prescribe these drugs? Detailed cost-effectiveness models addressing this question have been published by Canadian~and American~ investigators. Now Pharoah and Hollingworth have added a British perspective that mirrors earlier findings. This modelling exercise has limitations, some candidly noted by the authors themselves. Yields of treatment are underestimated because cumulative survival gains are projected over only a 10year time horizon - too short for preventive interventions of this nature. The model includes only persons aged 45-64 years, with a few risk factor subgroups, e.g. by age, sex, previous angina, previous MI and total serum cholesterol quintile. Factors such as smoking, diabetes, hypertension and HDL cholesterol levels are not included. The costing does not tally detection costs or economic benefits arising from morbid events averted. Tradeoffs and opportunity costs are not clearly addressed. For example, if a health authority opted for restricted rather than general use of statins, what other services could it purchase with the savings? Physician-readers will be justifiably skeptical about rationing by assumptionladen mathematical models? Indeed, few economists are sanguine about defining the point at which treatment should be deemed 'unaffordable'. Perhaps the key implication of this and similar analyses is to reinforce clinical common sense, i.e. use these (and all) expensive drugs prudently in patients who have the most to gain from them.
C. David Naylor, MD, DPHIL,FRCPC University of Toronto, Toronto, Ontario, Canada Other sources 1. Hamilton VH, Racicot FE, Zowail H, Coupal L, Grover SA. JAMA 1995 Apt 5; 273(13). 1032-1038 2. Goldman L, Weinstein MC, Goldman PA, Williams LW. JAMA 1991 Mar 6; 265(9): 1145-1151 3. Naylor D. ACP J Club 1996 Jan-Feb; 124(1): A12-A14
APRIL 1997
Pharoah PDP, Hollingworth W. Cost effectiveness of lowering cholesterol concentration with statins in patients with and without pre-existing coronary heart disease: life-table method applied to a health authority population. BMJ 1996; 312:1443-1448
Objective To determine the cost-effectiveness of lowering serum cholesterol with statins in men and women with varying risk of fatal coronary artery disease.
Design A mathematical model was constructed, based on life-table methodology, that was used to estimate the benefit on survival of treating men and women, aged 45-64 years, with a statin for 10 years.
Setting Population of a typical district health authority in the UK.
Subjects An imaginary cohort of men and women, aged 45-64 years, with and without pre-existing coronary artery disease.
Intervention Estimates for treatment effect were obtained from published randomized clinical trials of primary and secondary prevention in which patients were allocated to either treatment with a statin or control group.
Main cost and outcome measures The cost of treatment with a statin was estimated by determining the direct costs of the drug offset by savings associated with lives saved and reductions in rates of non-fatal myocardial infarctions (MI), coronary angiograms and revascularization
26
procedures. The main outcome measure was cost per life year saved.
Main results Five groups of patients, with decreasing risk of fatal coronary artery disease, were defined which would be considered eligible for treatment with a statin for primary or secondary prevention: group 1, men aged 45-64 and women aged 55-64 with previous MI and cholesterol > 5.4 mmol/L; group 2, men aged 45-64 and women aged 55-64 with angina and cholesterol > 5.4 retool/L; group 3, men aged 55-64 with no history of coronary heart disease and cholesterol > 6.5 mmol/L; group 4, women aged 45-54 with angina or previous MI and cholesterol > 5.4 mmol/L; and group 5, men aged 45-54 with no history of coronary heart disease and cholesterol > 6.5 mmol/L. The cost-effectiveness varied greatly between risk groups with a cost per life year saved of £16 000 in the highest risk group and £230 000 in the lowest risk group. Conclusion The cost-effectiveness of treating hypercholesterolemia with statins is dependent on the patient' s risk for coronary artery disease. Treating patients at highest risk is most cost-effective. Treatment of all eligible patients for both primary and secondary prevention would be prohibitively expensive.
EVIDENCE-BASED CARDIOVASCULAR MEDICINE
Commentary A decade of randomized trials has shown that the 'statins' are effective in both the primary and secondary prevention of coronary events. For secondary prevention, statins clearly have a favorable impact on all-cause mortality. A logical question arises: can we afford to prescribe these drugs? Detailed cost-effectiveness models addressing this question have been published by Canadian~and American~ investigators. Now Pharoah and Hollingworth have added a British perspective that mirrors earlier findings. This modelling exercise has limitations, some candidly noted by the authors themselves. Yields of treatment are underestimated because cumulative survival gains are projected over only a 10year time horizon - too short for preventive interventions of this nature. The model includes only persons aged 45-64 years, with a few risk factor subgroups, e.g. by age, sex, previous angina, previous MI and total serum cholesterol quintile. Factors such as smoking, diabetes, hypertension and HDL cholesterol levels are not included. The costing does not tally detection costs or economic benefits arising from morbid events averted. Tradeoffs and opportunity costs are not clearly addressed. For example, if a health authority opted for restricted rather than general use of statins, what other services could it purchase with the savings? Physician-readers will be justifiably skeptical about rationing by assumptionladen mathematical models? Indeed, few economists are sanguine about defining the point at which treatment should be deemed 'unaffordable'. Perhaps the key implication of this and similar analyses is to reinforce clinical common sense, i.e. use these (and all) expensive drugs prudently in patients who have the most to gain from them.
C. David Naylor, MD, DPHIL,FRCPC University of Toronto, Toronto, Ontario, Canada Other sources 1. Hamilton VH, Racicot FE, Zowail H, Coupal L, Grover SA. JAMA 1995 Apt 5; 273(13). 1032-1038 2. Goldman L, Weinstein MC, Goldman PA, Williams LW. JAMA 1991 Mar 6; 265(9): 1145-1151 3. Naylor D. ACP J Club 1996 Jan-Feb; 124(1): A12-A14
APRIL 1997