Influence of prior transient ischaemic attack on stroke prognosis

Background To evaluate potential neuroprotection afforded by prior transient ischaemic attack (TIA) on functional and survival outcomes after ischaemic stroke. Methods All cases of first-ever ischaemic strokes, diagnosed between 1985 and 2008, were identified from the Dijon Stroke Registry. Patients were analysed in three groups according to the time interval between prior TIA and stroke (<4 weeks, >= 4 weeks, no TIA) or the duration of TIA (<= 30 min, > 30 min, no TIA). Outcomes were severe functional handicap (unable to walk, bedridden or death) at hospital discharge or at outpatient consultation, and 1-month and 1-year any-cause mortality. Stratified analyses were performed by stroke subtypes (non-lacunar, lacunar). Generalised linear mixed models and Cox proportional hazard models with a sandwich covariance matrix accounting for the treatment centre as a random effect were used for multivariate analyses. Results Among the 3015 patients with first-ever ischaemic stroke, 389 had had a prestroke TIA <4 weeks and 97 a prestroke TIA >= 4 weeks. Patients with TIAs had better ambulatory status (adjusted OR 0.61, 95% CI 0.45 to 0.81; p=0.008) and better survival at 1 month (adjusted HR 0.76, 95% CI 0.65 to 0.89; p=0.0006) and at 1 year (adjusted HR 0.72, 95% CI 0.67 to 0.76; p<0.0001) than those with no TIAs. Prestroke TIA <4 weeks and TIA duration <= 30 min also significantly improved the outcomes in overall, non-lacunar and lacunar strokes. Conclusions Recent prestroke TIA was associated with better functional outcome and lower 1-month and 1-year mortality after stroke, suggesting a neuroprotective effect.