Supplementary Material for: Are Early Seizures Predictive of Epilepsy after a Stroke? Results of a Population-Based Study

Background: In addition to determining the cumulative incidence and risk factors for early seizures (ES), late seizures (LS) and post stroke epilepsy (PSE), we aimed at checking if ES represented a risk factor for epilepsy and if early treatment after ES prevented the occurrence of subsequent seizures. Methods: This study was part of a 2-year prospective community-based registry of all cerebrovascular events in the district of Udine (153,312 inhabitants), North-Eastern Italy, between April 1, 2007 and March 31, 2009. People with transient ischemic attacks (TIAs) were excluded from this study. Results: In all, 782 cases of stroke (79.28% ischemic, 14.83% hemorrhagic, 3.20% subarachnoid hemorrhage and 2.69% undetermined) were identified. The incidence of ES, LS and PSE was 5.10, 3.14 and 2.22%, respectively. Intracerebral hemorrhage, subarachnoid hemorrhage, stroke of undetermined origin and hyponatremia, represented risk factors for ES (p < 0.05). Among ischemic strokes, ES risk factors were hyponatremia (p = 0.024) and hemorrhagic transformation (p = 0.046). LS risk factors were younger age (p = 0.004) and cortical location of stroke (p = 0.004). Within ischemic strokes, LS risk factors were younger age (p = 0.020) and cortical location (p < 0.0001). Within intracerebral hemorrhages, the only risk factor for LS was the presence of a previous ES (p = 0.017). PSE risk factors were the same as for LS. Conclusions: All acute conditions related to the occurrence of stroke are implicated in the pathogenesis of ES, which becomes a risk factor for LS only in the setting of intracerebral hemorrhages. Therefore, early antiepileptic treatment is needed only in this situation.