A possible role of ID-Migraine in the emergency department: study of an emergency department out-patient population.

Headache symptoms account for 1-3% of admissions to an emergency department (ED). Most patients affected by a primary headache (PH) have migraine, although they are often misdiagnosed as 'headache not otherwise specified'. We investigated the possibility of using ID-Migraine (ID-M) to improve migraine recognition in the ED setting. We planned a pilot study involving ED out-patients with a diagnosis of PH. Diagnoses of a blinded headache expert were subsequently matched with the ID-M results. We tested ID-M on 230 patients (199 PH, 31 secondary headaches). Considering only PH, ID-M exhibited a sensitivity of 0.94 and specificity of 0.83 with a positive predictive value (PPV) of 0.99. The ID-M is a simple migraine screener with high sensitivity, high specificity and high PPV, even in an ED-derived population. Methodical use of this tool in an ED setting may, once a secondary headache has been excluded, lead to rapid diagnosis of migraine.