Cost-effectiveness of HMG coenzyme reductase inhibitors; whom to treat?

Abstract

Aims: Treatment guidelines have been developed for both "primary" and "secondary" prevention of coronary heart disease. These should consider both the efficacy as well as the costs of such treatment, particularly the costs of treatment with HMG co-enzyme A reductase inhibitors (statins). In the context of guideline development in The Netherlands, the cost effectiveness of treatment with statins was analysed.

Methods: Following a modelling approach, cost effectiveness was analysed as a function of a patient's initial risk for new coronary heart disease events, combining results from 4S, CARE, LIPID, WOSCOPS and AFCAPS with Dutch cost data. For each sex and age group, an estimate was made of the level of cardiovascular risks that might correspond to a cost-effectiveness ratio under NLG 40 000 (Euro 18 151) per life year gained.

Results: If the 10-year risk of myocardial infarction, stroke or cardiovascular death was estimated at 9% (AFCAPS/TexCAPS), 20% (WOSCOPS), 36% (CARE) 36% (LIPID) and 47% (4S), cost effectiveness was estimated at Euro 51 400, Euro 26 013, Euro 9970, Euro 8028 and Euro 6695. The arbitrary threshold of NLG 40 000 (approximately Euro 18 000) was achieved at a 10 year coronary heart disease event risk ranging from 19% to 26% for different age groups. Assuming the effectiveness of statin treatment decreased with age, a 10-year risk, corresponding to Euro 18 000, varied from 11% (under age 30) to 41% (over age 80). Patients at higher risk levels should be considered for statin therapy.

Conclusions: Treatment costs for primary or secondary prevention are determined predominantly by the costs of statin drugs. The developed model allows comparison of cost effectiveness of statin therapy across a wide range of subjects with or without coronary heart disease. The consensus committee in the Netherlands postulated that drug therapy should be considered in subjects with or without coronary heart disease in which cost-effectiveness is similar. Such groups can be identified using the presented model. When cost effectiveness ratios up to Euro 18 000 per life year gained are deemed acceptable, statin treatment should be considered in most patients with known cardiovascular disease (secondary prevention), and in a limited group of subjects who are at high risk of developing coronary heart disease (primary prevention).