Cost-effectiveness of cholesterol lowering varied greatly by cardiovascular risk
ACP J Club. 1996 Nov-Dec;125:81. doi:10.7326/ACPJC-1996-125-3-081
Pharoah PD, 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 health authority population. BMJ. 1996 Jun 8;312:1443-8. [PubMed ID: 8664620]
To determine the cost-effectiveness of lowering cholesterol levels with statins in patients with and without preexisting coronary heart disease.
A life table method was used to model the effect of statin treatment on survival over 10 years.
Typical district health authority in the United Kingdom.
Imaginary cohort of men and women aged 45 to 64 years who had and who did not have preexisting coronary heart disease.
Patients treated with a statin were compared with patients allocated to a control group.
Main cost and outcome measures
Costs per life-year saved. The costs of the intervention were estimated from the direct costs of treatment, offset by savings associated with reductions in coronary angiographies, nonfatal myocardial infarctions, and revascularization procedures.
For men aged 45 to 64 years who had no history of coronary heart disease and a cholesterol level > 6.5 mmol/L, the average cost-effectiveness of treatment with a statin for 10 years was £136 000 per life-year saved. For men and women aged 45 to 64 years who had preexisting coronary heart disease and a cholesterol level > 5.4 mmol/L, the average cost-effectiveness was £32 000 per life-year saved. The cost-effectiveness varied greatly between risk groups. It ranged from £6000 per life-year saved in men aged 55 to 64 years who had a cholesterol level > 7.2 mmol/L and had had a myocardial infarction to £361 000 per life-year saved in women aged 45 to 54 years who had a cholesterol level between 5.5 mmol/L and 6.0 mmol/L and angina. In the sensitivity analysis, effectiveness of treatment had the greatest influence on cost-effectiveness.
The cost-effectiveness of treating hypercholesterolemia with statins varied greatly between different risk groups and was greatest in patients with the highest risk for coronary heart disease. Treatment of all patients, regardless of risk profile, would be prohibitively expensive.
Source of funding: None.
For article reprint: Dr. P.D. Pharoah, Department of Community Medicine, Institute of Public Health, Cambridge CB2 2SR, England, UK. FAX 44-1223-330315.
The effectiveness of statins in reducing morbidity and mortality among patients with elevated serum cholesterol levels is supported by the results of the Scandinavian Simvastatin Survival Study (4S) (1) and more recently by the West of Scotland Coronary Prevention Study (2). The 4S showed that statins were effective in patients with established coronary heart disease (secondary prevention), and the West of Scotland study showed that statins were beneficial and safe in patients who did not have coronary heart disease (primary prevention) but had moderately increased cholesterol levels. Between 20% and 40% of adults in Western countries would have been eligible to enter 1 of these trials or the other and might have benefited from treatment, but statins typically cost $600 to $700 per patient per year. Hence, a range of important clinical, public health, and economic issues are at stake.
Schectman and colleagues produced evidence consistent with that from previous studies showing that health professionals working as physician extenders can be more effective than physicians in reducing LDL cholesterol levels. They also showed that physician extenders were more costly but more cost-effective; that is, they achieved a lower cost-per-unit reduction in LDL cholesterol level than did conventional care.
Readers may wish to consider whether the niacin-first strategy makes clinical or economic sense, particularly because reported adherence to niacin therapy was low and adverse events were frequent. The intervention was evaluated as a package, and data on the marginal costs and effectiveness of each step along the treatment algorithm were not reported. Therefore, the study is more valuable in relation to the mode of treatment delivery than for details about the treatment itself.
Pharoah and Hollingworth concentrate on variations in effectiveness and cost among different treatment groups. The cost data are the least refined part of their study and could be improved by direct evidence of changes in resource use and costs after the interventions reported in the 4S and West of Scotland Coronary Prevention Study. This evidence was recently published (3).
In deciding which patients should be treated while taking into account total treatment costs and average and marginal cost-effectiveness data, Pharoah and Hollingworth present 5 groups of patients at decreasing risk for coronary heart disease, all of whom fulfill the criteria for intervention used in the 4S or West of Scotland Coronary Prevention Study: group 1 (highest risk), men aged 45 to 64 years and women aged 55 to 64 years with previous myocardial infarction and a cholesterol level > 5.4 mmol/L; group 2, men aged 45 to 64 years and women aged 55 to 64 years with angina and a cholesterol level > 5.4mmol/L; group 3, men aged 55 to 64 years with no history of coronary heart disease and a cholesterol level > 6.5 mmol/L; group 4, women aged 45 to 54 years with angina or previous myocardial infarction and a cholesterol level > 5.4 mmol/L; group 5 (lowest risk), men aged 45 to 54 years with no history of coronary heart disease and a cholesterol level > 6.5 mmol/L. In summary, secondary prevention is recommended for both older men and women, whereas primary prevention is less cost-effective and is listed only for men with a serum cholesterol level > 6.5 mmol/L.
These groups provide for straightforward clinical application of the results of the study. But they reflect a failing of existing trials in this field, a failing that several reviews have identified (4): They focus primarily on white middle-aged adults (predominantly men). Nevertheless, the work should be helpful in developing practice recommendations.
Alastair Gray, DPhil
University of OxfordOxford, England, United Kingdom
1. Scandinavian Simvastatin Survival Study Group. Randomised trial of cholesterol lowering in 4444 patients with coronary heart disease: the Scandinavian Simvastatin Survival Study (4S). Lancet. 1994;334:1383-9.