Risk of stroke, myocardial infarction, coronary intervention, and atrial fibrillation or flutter in individuals experiencing typical migraine aura without headache: a Danish registry-based cohort study

BACKGROUND: Migraine aura without headache was previously described as a benign condition. We investigated an association between migraine aura without headache and risks of stroke, myocardial infarction (MI) or percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG), atrial fibrillation or flutter, and composite outcome (MI, PCI, and CABG). METHODS: We conducted a nationwide, registry-based cohort study in Denmark in 2003-18, which included 755 individuals with typical aura without headache, 11 420 individuals who experience migraine with aura, 13 415 individuals who experience migraine without aura, 12 000 individuals with unspecified migraine, and a comparison cohort of 702 755 individuals aged 15-80 years randomly sampled from the general population. We computed incidence rates (IRs) per 1000 person-years (PYs) of the outcomes and hazard ratios (aHRs) adjusted for age, sex, calendar year, and pre-existing chronic conditions in Cox proportional-hazards regression analyses. RESULTS: The IR per 1000 PYs among individuals experiencing aura without headache were 4.58 (2.09-7.07) for stroke, 2.10 (0.42-3.79) for MI or PCI, 0.69 (0.00-1.66) for CABG, and 4.95 (2.35-7.54) for atrial fibrillation or flutter. Individuals who experience aura without headache versus the comparator had increased risks of stroke [aHR: 2.58, 95% confidence interval (CI): 1.49-4.44] and atrial fibrillation or flutter (aHR: 2.22, 1.31-3.75). Associations with MI or PCI (aHR: 1.56, 0.70-3.47), CABG (aHR: 2.66, 0.66-10.65), and composite outcome (aHR: 1.65, 95% CI: 0.79-3.46) were in the same direction, but lacked precision. CONCLUSION: Aura without headache was associated with increased risks of stroke and atrial fibrillation or flutter; associations with remaining outcomes could not be ruled out.