At what coronary risk level is it cost-effective to initiate cholesterol lowering drug treatment in primary prevention?

BACKGROUND: The entire risk factor profile should be taken into account when considering initiating cholesterol lowering drug treatment. Recent treatment guidelines are therefore based on the absolute risk of coronary heart disease. We estimated at what coronary risk it is cost-effective to initiate cholesterol lowering drug treatment in primary prevention for men and women of different ages in Sweden. METHODS: The cost-effectiveness was estimated as the incremental cost per quality-adjusted life-year (QALY) gained of cholesterol lowering drug treatment. Treatment was assumed to lower the risk of coronary heart disease by 31%. The analysis was carried out from a societal perspective including both direct and indirect costs of the intervention and morbidity, and the full future costs of decreased mortality. The coronary risk, in a Markov model of coronary heart disease, was raised until the cost per QALY gained corresponded to a specific threshold value per QALY gained. Three different threshold values were used: $40,000, $60,000 and $100,000 per QALY gained. RESULTS: The risk cut-off value for when treatment is cost-effective varied with age and gender. If society is willing to pay $60,000 to gain a QALY it was cost-effective to initiate treatment if the 5-year-risk of coronary heart disease exceeded 2.4% for 35-year-old men, 4.6% for 50-year-old men, and 10.4% for 70-year-old men. The corresponding risk cut-off values for women were 2.0%, 3.5% and 9.1%. CONCLUSIONS: The results can serve as a basis for treatment guidelines based on cost-effectiveness.