Fig. 1From: Characterizing healthcare utilization patterns in a Danish population with headache: results from the nationwide headache in Denmark (HINDER) panelParticipant flow diagram. The campaign link was accessed 16,168 times with 4,708 acceptances of the invitation to participate. After exclusion of duplicates, the number of participants included in the HINDER panel was 4,431, of whom 2,990 completed all questions of the Healthcare Utilization ModuleBack to article page