Clinical and Demographical Characteristics of Patients with Medication Overuse Headache in Argentina and Chile: Analysis of the Latin American Section of COMOESTAS Project

Background: Data on the characteristics of Medication Overuse Headache (MOH) in Latin American (LA) are scarce. Here we report the demographic and clinical features of the MOH patients from Argentina and Chile enrolled in the multinational COMOESTAS project in the period 2008–2010. Methods: The LA population was formed by 240 MOH subjects, 110 from Chile and 130 from Argentina, consecutively attending the local headache centres. In each centre, specifically trained neurologist interviewed and confirmed the diagnosis according to the ICHD-II criteria. A detailed history was collected on an electronic patient record form. Results: The mean patient age was 38.6 years, with a female/male ratio of 8:2. The mean time since onset of the primary headache was 21 years, whereas duration of MOH was 3.9 years. The primary headache was migraine without aura in 77.5 % and migraine with aura in 18.8 %. Forty two % of the patients self-reported emotional stress associated with the chronification of headache; 43.8 % reported insomnia. The most overused medications were acute drug combinations containing ergotamine (70 %), NSAIDs (33.8 %) and triptans (5.4 %). Conclusion: Though little described, MOH is present also in LA, where it affects mostly women, in the most active decades of life. Some differences emerge as regards the demographic and clinical characteristics of MOH in this population as compared to Europe or Northern America. What seems more worrying about MOH in Argentina and Chile is that most patients overuse ergotamine, a drug that may cause serious adverse events when used chronically. These findings once more underscore the importance of properly diagnose and treat MOH.