Economic burden and costs of chronic migraine.

Chronic migraine (CM) is a subtype of migraine broadly defined by the presence of headache at least 15 days per month. Emerging evidence suggests that CM and episodic migraine (EM) differ not only in headache frequency, but that they are distinct clinical entities. Because individuals with CM are more disabled, they demonstrate higher societal burden than those with EM. There have been three important surveys published within the last five years that have focused on the societal burden associated with CM. The first is the American Migraine Prevalence and Prevention (AMPP) study, a longitudinal population-based survey performed in the U.S. The second, the International Burden Migraine Study (IBMS), is a Web-based survey conducted in North America, Western Europe, Asia/Pacific, and Brazil. The third is a clinic-based survey performed in Taiwan. This review discusses results of these studies with regard to healthcare resource use (and related direct costs) and loss of productivity (and related indirect costs) from the perspective of cost-effectiveness of new therapeutic approaches to CM.