Abstract Body: Introduction: Patients experiencing a transient ischemic attack (TIA) or minor stroke have a high long-term risk of subsequent stroke that persists for over one year following presentation. While risk stratification tools like the ABCD² score have been used to identify patients at high risk of stroke in the short-term (within the first 90 days), less is known about factors that determine long-term risk. Some studies suggest that traditional predictors of early stroke risk may not be associated with long-term risk, while others have reported conflicting results. We aimed to summarize the association between clinical, demographic, imaging factors and the long-term risk of stroke in patients experiencing TIA or minor stroke.

Methods: We searched MEDLINE, Embase, and the Web of Science from inception to June 2024, for observational studies that examined factors associated with subsequent stroke in patients experiencing TIA or minor stroke during a minimum follow-up of one year. Two reviewers independently performed study screening and data extraction. For the primary analysis, we included prognostic factors if they were derived from a multivariable Cox proportional hazards model and reported in at least 2 studies. We contacted the corresponding authors of the studies to obtain adjusted effect estimates when these values could not be extracted from the reported data. We conducted random effects meta-analyses of adjusted hazard ratios and report pooled effect estimates with 95% confidence intervals.

Results: Of 13051 citations identified, we included 28 studies examining 85,328 patients including unpublished data from 8 studies that we directly obtained from study authors. Factors associated with an increased risk of stroke at one year or beyond included male sex, older age, hypertension, diabetes mellitus, atrial fibrillation, history of stroke or TIA before the qualifying event, history of coronary artery disease, presence of hemiparesis, aphasia, baseline ABCD² score of 4 or greater, acute infarct on brain imaging, large-artery atherosclerosis, and cardioembolism (Figure 1).

Conclusion: We have identified important prognostic factors associated with long-term risk of stroke after a TIA or minor stroke. These findings provide a framework for evidence-based risk stratification of patients who may require extended treatment and vigorous monitoring.