DOES PREVIOUS TRANSIENT ISCHEMIC ATTACK INFLUENCE ISCHEMIC STROKE PROGNOSIS? u2013 SYSTEMATIC REVIEW AND META-ANALYSIS

TitleDoes previous transient ischemic attack influence ischemic stroke prognosis? u2013 Systematic review and meta-analysisIntroductionObservational studies have shown conflicting results about the impact of previous transient ischemic attack (prev-TIA) on ischemic stroke (IS) prognosis. Although ischemic preconditioning has been suggested as a potential neuroprotective mechanism, secondary prevention treatment after a first TIA could explain better outcomes in the future. We aimed to conduct a systematic review and meta-analysis of observational studies designed to study the influence of prev-TIA on IS prognosis.MethodsWe analysed studies indexed to MEDLINE, Embase and Scopus (up to October 2017), reporting IS outcome according to the occurrence of prev-TIA. Studies were grouped according to their definition of good outcome. We used a random-effects model to pool effect on outcome according to prev-TIA. Meta-regression model was used to explore the potential effect of preadmission antithrombotics on outcome.Results15 studies were selected including 22335 patients, 2350 (10.5%) with prev-TIA. Two subgroups were defined: 1) good outcome at discharge (modified Rankin Scale u2264 1), 3 studies, 12358 patients, 795 (6.4%) with prev-TIA; 2) good outcome at 3 months (modified Rankin Scale u2264 1), 4 studies, 813 patients, 238 (29.3%) with prev-TIA. Both at discharge and at 3 months, prev-TIA was associated with better outcomes (OR: 1.37; CI 95% 1.12 u2013 1.68 and OR: 2.29; CI 95% 1.59 u2013 3.29). Meta-regression analyses did not revealed a significant effect of preadmission antithrombotics on 3-month outcome (CI 95% -0.007 u2013 0.006; p=0.912).ConclusionsPrevious TIA may have an impact on ischemic stroke prognosis independently of preadmission antithrombotics. The high heterogeneity between studies on outcome assessment precluded more comprehensive results.