Fig. 4From: Long-term study of the efficacy and safety of OnabotulinumtoxinA for the prevention of chronic migraine: COMPEL studyLong-term effect of onabotulinumtoxinA on number of and change vs baseline. a) Number of headache days and b) number of moderate or severe headache days per 28-d period preceding the visit over 108 wk. (depicting the outcomes of treatment after 9 cycles). *P < 0.0001; paired t-test used to compare visit to baselineBack to article page