title: When does chronic migraine strike? A clinical comparison of migraine according to the headache days suffered per month.
abstract: Introduction According to the IHCD-3β classification, chronic migraine (CM) is headache occurring on 15 or more days/month. Episodic migraine (EM) can be divided into low frequency (LFEM) and high frequency (HFEM) depending on the headache days suffered per month. Methods We performed a clinical comparison of migraine characteristics according to monthly headache days suffered. Patients were divided into three groups: LFEM (1-9 headache days/month), HFEM (10-14 headache days/month) and CM (≥15 headache days/month). Results The analysis included 1109 patients. Previously reported differences between EM and CM were replicated. However, there were three times more clinical differences between LFEM and HFEM than between HFEM and CM (15 vs. 6). A new model that takes 10 headache days as a cut-off value for CM would have a minimally higher predictive capacity (72.8%) and no statistical differences (71.8%) when comparing it to the current classification. Conclusions HFEM patients have few clinical differences compared with CM patients. This includes the poor outcomes regarding headache-related disability and impact on daily life. According to these findings, neurologists and headache specialists should consider that the emotional and functional impact in HFEM patients could be as disabling as in those with CM.
authors.affiliation: 1 Headache and Pain Research Group, Vall d'Hebron Research Institute (VHIR), Universitat Autònoma de Barcelona, Spain.|2 Neurology Department, Hospital Universitari Vall d'Hebron (HUVH), Spain.
authors.forename: M
authors.initials: M
authors.lastname: Torres-Ferrús
authors.affiliation: 2 Neurology Department, Hospital Universitari Vall d'Hebron (HUVH), Spain.
authors.forename: M
authors.initials: M
authors.lastname: Quintana
authors.affiliation: 1 Headache and Pain Research Group, Vall d'Hebron Research Institute (VHIR), Universitat Autònoma de Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Fernandez-Morales
authors.affiliation: 2 Neurology Department, Hospital Universitari Vall d'Hebron (HUVH), Spain.
authors.forename: J
authors.initials: J
authors.lastname: Alvarez-Sabin
authors.affiliation: 1 Headache and Pain Research Group, Vall d'Hebron Research Institute (VHIR), Universitat Autònoma de Barcelona, Spain.|2 Neurology Department, Hospital Universitari Vall d'Hebron (HUVH), Spain.
authors.forename: P
authors.initials: P
authors.lastname: Pozo-Rosich
mesh_terms: D000328:Adult; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000175:diagnosis* / Q000453:epidemiology* / Q000523:psychology; D011446:Prospective Studies; D011788:Quality of Life / Q000523:psychology; D013997:Time Factors
keywords: Headache; MIDAS; chronic migraine; disability; migraine