Migraine Headache Day is a calendar day on which a migraine or probable migraine headache occurs. Per International Headache Society \[IHS\] International Classification of Headache Disorders version 3 \[ICHD-3\], migraine is defined as a headache, with or without aura, of \>=30 minutes duration with both of the following required features (A) At least 2 of the following headache characteristics: Unilateral location; Pulsatile quality; Moderate or severe pain intensity; Aggravation by or causing avoidance of routine physical activity (B) During headache at least 1 of the following: Nausea and/or vomiting; Photophobia and phonophobia. Least square mean was assessed using Bayesian Mixed Model Analysis with baseline number of monthly migraine headache days as a covariate.