Defining migraine days, based on longitudinal E-diary data.

Background: There is a need for standardization of the definition of a migraine day for clinical and research purposes.

Methods: We prospectively compared different definitions of a migraine day with E-diary data of n = 1494 patients with migraine. We used a baseline definition based on migraine characteristics with a duration of ≥4 hours OR triptan intake (independently from its effect) OR (visual) aura lasting 5-60 minutes.

Results: Of all migraine days defined by triptan intake only, 66.2% had a duration <4 hours. Adjusting the headache duration criterion to ≥30 minutes led to a decrease in days defined by triptan intake only and resulted in a 5.4% increase in total migraine days (equals 0.45 migraine day increase in monthly migraine days). These additional migraine days had a median duration of 2.5 hours.

Conclusion: We propose to define a migraine day as follows: 1) (a) headache duration ≥30 minutes; (b) matching ≥2 of four characteristics: unilateral, pulsating, moderate to severe pain, aggravation by or causing avoidance of routine physical activity; and (c) during headache ≥1 of the following: nausea and/or vomiting, photophobia and phonophobia or 2) (visual) aura duration 5-60 minutes or 3) a day with headache for which acute migraine-specific medication is used irrespective of its effect.