Ninety-Day Stroke Recurrence in Minor Stroke: Systematic Review and Meta-Analysis of Trials and Observational Studies

Risk of recurrence after minor ischemic stroke is usually reported with transient ischemic attack. No previous meta-analysis has focused on minor ischemic stroke alone. The objective was to evaluate the pooled proportion of 90-day stroke recurrence for minor ischemic stroke, defined as a National Institutes of Health Stroke Scale severity score of ≤5.

Published papers found on PubMed from 2000 to January 12, 2021, reference lists of relevant articles, and experts in the field were involved in identifying relevant studies. Randomized controlled trials and observational studies describing minor stroke cohort with reported 90-day stroke recurrence were selected by 2 independent reviewers. Altogether 14 of 432 (3.2%) studies met inclusion criteria. Multilevel random-effects meta-analysis was performed. A total of 6 randomized controlled trials and 8 observational studies totaling 45 462 patients were included. The pooled 90-day stroke recurrence was 8.6% (95% CI, 6.5-10.7), reducing by 0.60% (95% CI, 0.09-1.1; P=0.02) with each subsequent year of publication. Recurrence was lowest in dual antiplatelet trial arms (6.3%, 95% CI, 4.5-8.0) when compared with non-dual antiplatelet trial arms (7.2%, 95% CI, 4.7-9.6) and observational studies 10.6% (95% CI, 7.0-14.2). Age, hypertension, diabetes, ischemic heart disease, or known atrial fibrillation had no significant association with outcome. Defining minor stroke with a lower National Institutes of Health Stroke Scale threshold made no difference - score ≤3: 8.6% (95% CI, 6.0-11.1), score ≤4: 8.4% (95% CI, 6.1-10.6), as did excluding studies with n<500%-7.3% (95% CI, 5.5-9.0).

The risk of recurrence after minor ischemic stroke is declining over time but remains important.