Genetic liability to migraine and functional outcome after ischemic stroke

Background and purpose: To evaluate the association of genetic liability to migraine with functional outcome after ischemic stroke using Mendelian randomization. Methods: Genetic proxies for migraine were obtained from the largest genome-wide association study meta-analysis of 102,084 migraine cases and 771,257 controls. Genetic associations with functional outcome after ischemic stroke were obtained from the Genetics of Ischemic Stroke Functional Outcome network study (N = 6021). Poor functional outcome after ischemic stroke was defined as a score of 3-6 on the modified Rankin scale at 3 months (N = 2280). The inverse-variance weighted method was used to estimate the association of genetic liability to migraine with functional outcome, and we performed sensitivity analyses to assess the robustness of results. Results: Genetic liability to migraine was associated with poor functional outcome after ischemic stroke (odds ratio of poor functional outcome per doubling in migraine odds 1.22, 95% confidence interval 1.02-1.45, p = 0.031). This association remained directionally consistent across sensitivity analyses. Conclusions: This study provides genetic support that migraine is associated with poor functional outcome after ischemic stroke. These findings warrant further follow-up and, if replicated, may have clinical implications for post-stroke recovery.