Background: Migraine, including episodic migraine (EM) and chronic migraine (CM), is a common neurological disorder that imparts a substantial health burden.
Objective: Understand the characteristics and treatment of EM and CM from a population-based perspective.
Methods: This retrospective population-based cross-sectional study utilized administrative data from Alberta. Among those with a migraine diagnostic code, CM and EM were identified by an algorithm and through exclusion, respectively; characteristics and migraine medication use were examined with descriptive statistics.
Results: From 79,076 adults with a migraine diagnostic code, 12,700 met the criteria for CM and 54,686 were considered to have EM. The majority of migraineurs were female, the most common comorbidity was depression, and individuals with CM had more comorbidities than EM. A larger proportion of individuals with CM versus EM were dispensed acute (80.6%: CM; 63.4%: EM) and preventative (58.0%: CM; 28.9%: EM) migraine medications over 1 year. Among those with a dispensation, individuals with CM had more acute (13.6 ± 32.2 vs. 4.6 ± 10.9 [mean ± standard deviation], 95% confidence interval [CI] 7.7-8.3), and preventative (12.6 ± 43.5 vs. 5.0 ± 12.6, 95% CI 6.9-8.4) migraine medication dispensations than EM, over 1-year. Opioids were commonly used in both groups (proportion of individuals dispensed an opioid over 1-year: 53.1%: CM; 25.7%: EM).
Conclusions: Individuals with EM and CM displayed characteristics and medication use patterns consistent with other reports. Application of this algorithm for CM may be a useful and efficient means of identifying subgroups of migraine using routinely collected health data in Canada.
Keywords: Chronic migraine; Comorbidity; Demographics; Episodic migraine; Medication use; Retrospective study.