Persistence and switching patterns of migraine prophylactic medications in Canada: A retrospective claims analysis comparing adherence and evaluating the economic burden of illness.

To describe patient characteristics, treatment patterns, and the burden of illness among adult migraine patients in Canada prescribed migraine prophylactics. Little is known about the relative persistence of treatments in the real-world setting and the impact of migraine prophylactic therapy on patients. As a result, migraine care in Canada continues to inadequately serve patients suffering from frequent headache days, reflecting a large unmet need. This retrospective study used Reformulary Group's longitudinal prescription claims database. Private payer data were analyzed to identify 2007 migraine prophylactic naïve patients, with a prior history of acute therapy, for tracking over 24 months to determine treatment patterns and costs. Patient flow is summarized in a Sankey diagram visualizing persistence and switching across different timepoints. Patient persistence to migraine prophylactic medications was low at 24.9% (n=500); Switching from index medications to another prophylactic medication was common (27%), however 50% of patients discontinued without switching. It was observed that acute treatment and opioid use were much lower when patients established and maintained therapy on migraine prophylactics. Overall, angiotensin receptor blockers and CGRP antagonists had high persistence but were underutilized therapies while the inverse was true for antidepressants and anticonvulsants. In a real-word setting, recognizing that many patients may discontinue preventative treatment completely after their first therapy, there is a need to employ migraine-specific prophylactics and/or tolerable medications early. Treatment guidelines aligned to costs savings and/or requiring step therapy may be inadvertently failing patients. Further, the impact of migraine on the day-to-day lives of patients and high societal costs such as its impact on productivity should be weighed in considering migraine's burden of illness and the benefits of treatment.