Economic evaluation of drug therapy for hypercholesterolaemia in the United Kingdom

The last decade has shown a concerted effort in the UK to find ways of reducing coronary heart disease (CHD), culminating in the recent government target of a 30% reduction in the rates in people under the age of 65 years to be achieved between 1988 and 2000 by modification of the main risk factors: diet, smoking and physical fitness. It is generally accepted that the best prospect for achieving this is a combination of a population based approach, aimed at changing behaviour across the whole population, and intensified advice and treatment to those at highest risk. Several reports have discussed the relative importance of elevated cholesterol (hypercholesterolaemia) as a risk factor for CHD and the pros and cons of more concerted efforts to identify individuals with high cholesterol levels, either by mass screening or by opportunistic testing by GPs. For individuals who are found to have hypercholesterolaemia, it is generally agreed that diet should be the first line therapy. However, when dietary measures fail to reduce cholesterol to target levels, do the benefits of drug therapy justify the costs? This paper assesses the cost-effectiveness of drug therapy for primary prevention of hypercholesterolaemia in patients for whom dietary measures have failed. The estimates of effectiveness, in life years gained, are based on a risk assessment model, using epidemiological data and the results from clinical trials of cholesterol-lowering drugs. The cost per life year gained for men from treatment with one of the newer drugs (simvastatin 20mg daily) ranged from £11,900 to £56,650, depending on age and pre-treatment cholesterol level. Cost-effectiveness ratios for women were substantially higher. Primary prevention by drug therapy is most cost-effective at pre-treatment levels of 8mmol/L and above, and when other risk factors are taken into account. IN this case the cost-effectiveness ratios are comparable with those for a number of current health care interventions in the UK. These estimates of cost-effectiveness are the best that can be obtained using currently available epidemiology data. Whether or not drugs lower overall mortality is still currently being debated. Further clinical trials are underway with adequate statistical power to assess whether the previously reported increase in non-CHD deaths in intervention studies is a chance finding or not.