Migraine preventive therapy is recommended for patients with frequent and chronic migraine, but the effectiveness of preventive medications was believed to be affected by MO [6]. Topiramate, a migraine preventive treatment, significantly reduced migraine days in patients with CM, but failed to reach significance in a post hoc analysis of patients with CM and MO, possibly due to a small sample size [21]. In one study of patients with MO who were unresponsive to preventive therapy, withdrawal of the overused medication increased the efficacy of preventive therapy [22]. However, in our study, more patients treated with fremanezumab had a ≥ 50% reduction in the monthly number of headache days of at least moderate severity, independent of baseline MO. This strongly suggests that MO has minimal, if any, impact on the efficacy of fremanezumab.