Choice of cost-effectiveness measure in the economic evaluation of cholesterol-modifying pharmacotherapy. An illustrative example focusing on the primary prevention of coronary heart disease in Canada.

OBJECTIVE: To evaluate the effect of using different cost-effectiveness measures in the economic evaluation of cholesterol-modifying pharmacotherapy. DESIGN AND
SETTING: An economic model was used to examine the extent to which the relative cost effectiveness of cholesterol-modifying agents varies depending upon the cost-effectiveness measure used. The perspective taken was that of the Canadian public healthcare system. PATIENTS: Individuals without coronary heart disease (CHD) with low-density lipoprotein cholesterol (LDL-C) levels in excess of 190 mg/dl.
INTERVENTIONS: Cholesterol-modifying pharmacotherapies available in Canada. MAIN OUTCOME MEASURES AND
RESULTS: Cost per 1% reduction in LDL-C level; incremental cost per life-year gained; least-cost agent achieving the LDL-C reduction required to meet the target level of 160 mg/dl; incremental cost per life-year gained of agents reaching the target LDL-C level of 160 mg/dl relative to no therapy; incremental cost per life-year gained of agents achieving the target LDL-C level of 160 mg/dl relative to the least-cost agent reaching the target. Each cost-effectiveness measure had a different informational content to decision-makers, both in terms of the usefulness of the information they provided, and in terms of the extent to which they showed one agent to be more cost effective than another. The most cost-effective treatment regimens were fluvastatin 20 mg per day, fluvastatin 40 mg per day, atorvastatin 10 mg per day and atorvastatin 20 mg per day, depending on the pretreatment LDL-C level and the cost-effectiveness measure used.
CONCLUSIONS: We recommend that the cost effectiveness of cholesterol-modifying pharmacotherapy be measured using incremental cost per life-year gained in reaching a predefined target LDL-C level.