Economic evaluation of anti-epileptic drug therapies with specific focus on teratogenic outcomes.

BACKGROUND Anti-epileptic drugs are known to be teratogenic, yet many women do need to continue the anti-epileptic drug use during pregnancy. OBJECTIVES To perform an economic evaluation of the anti-epileptic drug choice in young women who potentially wish to become pregnant. In particular, to estimate the impact of teratogenicity on the costs per quality adjusted life year (QALY). METHODS A decision-tree model is used to calculate the costs per QALY, taking into account the malformation risk in offspring due to the exposure to carbamazepine, lamotrigine or valproic acid, based on the European birth cohort of 2007. Probabilistic sensitivity analyses were performed using Monte Carlo simulation. RESULTS Valproic acid is dominated by carbamazepine after rank ordering on costs. The incremental cost-effectiveness of lamotrigine vs carbamazepine was estimated at €175,534 per QALY. Although valproic acid was dominated by carbamazepine in terms of costs and related effects, it is clinically relevant to compare lamotrigine with valproic acid. In particular, treatment options are dependent on several individual and clinical characteristics and these agents are therefore not always considered as interchangeable for all specified populations. The incremental cost-effectiveness for lamotrigine vs valproic acid was estimated at €13,370 per QALY. With assuming a willingness to pay threshold of €50,000 per QALY, results from the probabilistic analysis resulted in an acceptance level for lamotrigine vs carbamazepine and lamotrigine vs valproic acid of 4% and 99%, respectively. CONCLUSION Based on epidemiological data it is advised to whenever possible avoid valproic acid during pregnancy. Both carbamazepine and lamotrigine are estimated to be cost-effective treatment options vs valproic acid if focused on teratogenicity.