Background: Multiple studies have identified migraine as a risk factor for stroke. The conclusions have often been contradictory and differ between subpopulations of migraine patients. No studies to date have assessed the risk of readmission for cerebrovascular events up to 1 year after an initial migraine admission. We sought to estimate readmission rates for acute ischemic stroke (AIS), transient ischemic attack (TIA), subarachnoid hemorrhage (SAH) and intracerebral hemorrhage (ICH) after an index admission for migraine, using nationally representative data.
Methods: The Nationwide Readmissions Database was designed to analyze readmissions for all payers and the uninsured, with data on >14 million U.S. admissions in 2013. We used International Classification of Diseases, Ninth Revision, Clinical Modification codes to identify index migraine admissions with and without aura or status migrainosus, and readmissions for cerebrovascular events. Cox proportional hazards regression was performed for each outcome with aura and status migrainosus as the main predictors. Models were adjusted for age and vascular risk factors.
Results: Out of 12448 index admissions for migraine, 9972 (80.1%) were women, mean age was 45.5±14.8 years, aura was present in 3038 (24.41%) and status migrainosus in 1798 (14.44%). The 30-day readmission rate (per 100,000 index admissions) was 197 for AIS, 86 for TIA, 42 for SAH, and 17 for ICH. In unadjusted models, aura (compared to no aura) was significantly associated with AIS (hazard ratio [HR] 1.53, 95% CI 1.04-2.24) and TIA (2.43, 1.39-4.24), but not ICH (1.86, 0.45-7.79) or SAH (1.84, 0.44-7.75). After adjustment for age and vascular risk factors, aura remained significantly associated with TIA (2.13, 1.22-3.74) but not AIS (1.38, 0.94-2.03). Status migrainosus (compared to no status), in adjusted models, was significantly associated with readmission for SAH (4.83, 1.09-21.42).
Conclusions: In this large, nationally representative database, migraine admission with aura was independently associated with TIA readmission, and status migrainosus was independently associated with SAH. Further research would clarify causal relationships underlying these strong associations.