Fig. 3

The distribution of non-overlapping headache frequency categories during the 12-month study. The distribution shown is based on unique categories defined by frequency of migraine headache days that were achieved for at least 3 consecutive months (A) and for at least 3 consecutive months and maintained until the patient’s endpoint (B). The percentage of all patients who shifted to < 4 migraine headache days/month, ≥ 4 migraine headache days/month but < 8 migraine headache days/month, and ≥ 8 migraine headache days/month, but < 15 headache days/month, as well as those who had CM frequency throughout, are shown for the proportion of patients who had a shift for ≥ 3 consecutive months (A) and for those who maintained that shift for ≥ 3 consecutive months and until the patient’s endpoint (B). Abbreviations: CM, chronic migraine; EM, episodic migraine; HDs, headache days; LFEM, low frequency episodic migraine; MHDs, migraine headache days; OLE, open-label extension; VLFEM, very low frequency episodic migraine