Increased Risk of Hemorrhagic Stroke in Patients with Migraine: A Population-Based Cohort Study

Objective: Previous studies on the association between migraine and the risk of developing hemorrhagic stroke (HS) have generated inconsistent results. The aim of the present population-based, age- and sex- matched follow-up study was to investigate whether migraine is associated with an increased risk of HS. Method: A total of 20925 persons with at least two ambulatory visits in 2001 with the principal diagnosis of migraine were enrolled in the migraine group. The non-migraine group consisted of 104625, age- and sex- matched, randomly sampled subjects without migraine. The two-year HS-free survival rates for these 2 groups were estimated using the Kaplan-Meier method. Cox proportional hazards regression was used to estimate the effect of migraine on the occurrence of HS. Results: During the 2 year follow-up, 113 subjects in the migraine group (0.54%) and 255 in the non-migraine group (0.24%) developed HS. The crude hazard ratio (HR) for developing HS in the migraine group was 2.22 compared to the non-migraine group (95 % confidence interval [CI]: 1.78–2.77, p,0.0001) and the adjusted HR was 2.13 (95 % CI: 1.71–2.67, p,0.0001) after controlling for demographic characteristics and comorbid medical disorders. Conclusions: This population-based age- and sex- matched cohort study shows that migraine was linked to an increase