Migraine is associated with a higher risk of transient global amnesia: A nationwide cohort study

Background and purpose: The association between migraine and transient global amnesia (TGA) is not determined. Only two clinic-based studies showed that TGA patients had a higher frequency of migraine history. Our population-based study aimed to investigate whether migraine patients were associated with a higher risk of developing TGA. Methods: Patients with migraine aged ≥18 years were identified from the Taiwan National Health Insurance Research Database between 2005 and 2009. Each migraine patient was randomly matched to one subject without migraine or other headache disorders based on age, sex and cardiovascular comorbidities. Patients with antecedent stroke, epilepsy or TGA were excluded. Both cohorts were followed up until the end of 2010. The incidence rates of TGA were compared and risk factors were identified. Results: A total of 158 301 patients in the migraine cohort and 158 301 patients in the matched control cohort were enrolled. During a mean follow-up of 3.0 years (range 0-6 years), the migraine cohort had a greater risk of developing TGA than the control cohort [7.59 vs. 3.06 per 100 000 person-years, incidence rate ratio (IRR) = 2.48, P = 0.002]. Compared with the matched cohort, only female migraine patients aged 40-60 years showed a significantly higher risk of TGA [IRR = 3.18 (1.31-8.82), P = 0.005]. Of note, the incidence rates did not differ between migraine patients with and without aura. Conclusions: This population-based study demonstrates that migraine is associated with an increased risk of TGA, particularly in female patients aged 40-60 years.