ObjectiveTo determine whether the utilization of healthcare resources is reduced after chronic migraine patients are treated for 6 months with onabotulinumtoxinA.BackgroundOnabotulinumtoxinA is indicated for headache prophylaxis in patients with chronic migraine, but its effect on healthcare resource use is unknown.MethodsWe analyzed data from an open-label study of 230 chronic migraine patients refractory to ≥2 oral prophylactics who presented to a headache specialty clinic and who were treated with two cycles of onabotulinumtoxinA. Frequency and cost of migraine-related healthcare resource use, including visits to emergency departments, urgent care, or hospitalization, were compared for the 6 months before and after initial treatment. Costs were based on publicly available sources.ResultsCompared with the 6 months predating initial treatment, patients had 55% fewer emergency department visits (174 vs 385), 59% fewer urgent care visits (61 vs 150), and 57% fewer hospitalizations (19 vs 45) during the 6-month treatment period (P < .01 for all). Analysis of treatment-related costs yielded an average reduction of $1219.33/patient, off-setting 49.7% of the total estimated cost for 6 months of treatment with onabotulinumtoxinA.ConclusionsAlthough we are unable to distinguish onabotulinumtoxinA's treatment effect from other potential confounding variables, our analysis showed that severely afflicted, treatment-refractory patients with chronic migraine experienced a significant cost-offset through reduced migraine-related emergency department visits, urgent care visits, and hospitalizations in the 6 months following treatment initiation of onabotulinumtoxinA. Future analyses will assess the longer-term effect of onabotulinumtoxinA treatment and the potential contribution of regression to the mean.