Risk of Recurrent Stroke, Mortality, and Intracerebral Hemorrhage in Patients With Atrial Fibrillation Detected Before or After a Stroke.

Background And Objectives: The risk of recurrent ischemic stroke, intracranial hemorrhage, and mortality in people with atrial fibrillation detected after stroke (AFDAS) is still unclear compared with people with known atrial fibrillation (KAF). We systematically reviewed the literature to provide updated estimates for the risk of recurrent stroke, intracerebral hemorrhage, and mortality in AFDAS compared with KAF.

Methods: Our protocol was registered in PROSPERO (CRD42024583064). Presentation followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Meta-Analysis of Observational Studies in Epidemiology guidelines. We searched MEDLINE, EMBASE, Cochrane CENTRAL, and MedRxiv up to August 28, 2024, for studies comparing AFDAS and KAF for the following outcomes of interest: recurrent ischemic stroke (primary), intracerebral hemorrhage, mortality, and any stroke recurrence. We included cohort, observational studies (either prospective or retrospective) and randomized controlled trials and excluded studies with less than 15 patients per group. Eligible studies were assessed for bias using the Risk of Bias in Non-Randomized Studies tool. We pooled study-level results through random-effect meta-analysis of risk ratios (RRs). We also performed prespecified sensitivity analysis for study quality, timing of search for AF, propensity score matching, and study data source (administrative vs local data), and we planned meta-regression analysis to test for the interaction of sex, comorbid cardiovascular risk factors, and anticoagulation status on the difference between AFDAS and KAF.

Results: Seventeen studies were retrieved (n = 113,365; n = 80,339; n = 33,026; female in KAF, 49.0%; female in AFDAS, 45.1%), eight of which had low risk of bias. Ischemic stroke recurrence was significantly lower in AFDAS compared with the KAF group (RR = 0.79, 95% CI = 0.66-0.95, = 70%; n = 10). Meta-regression analysis revealed no interaction of anticoagulation, CHADS-VASc score, or sex on the difference in risk of recurrent ischemic stroke between groups. Mortality was lower in the AFDAS group compared with KAF (RR = 0.84, 95% CI = 0.74-0.95, = 74%; n = 14). The rates of any intracerebral bleeding (RR = 0.97, 95% CI = 0.68-1.39, = 58%; n = 5) and any stroke recurrence (RR = 0.99, 95% CI = 0.75-1.30; = 60; n = 3) were similar in AFDAS and KAF.

Discussion: AFDAS may carry a lower risk of ischemic stroke recurrence and mortality compared with KAF, with similar risk of intracerebral hemorrhage. Stratification through implementation of AF burden measures may support more personalized management for people with AFDAS.