Seizure 47, 2017: Incidence of seizures following initial ischemic stroke in a community-based cohort: The Framingham Heart Study
Although epilepsy is a chronic disorder the vast majority of research studies guiding decisions about treatment often continued for decades have involved follow-up periods of a small number of weeks or months. Longer-term research is hard to do, not only in people with seizures. It is tricky to predict questions, which will still be relevant after five, ten or twenty years. It is difficult to track participants over long periods of time. A gradual attrition of participant numbers has to be expected, and studies have to be sufficiently large at the outset to allow for such losses. All of this increases research costs.
One of the first major studies to buck the trend towards following participants up for the shortest possible length of time is the Framingham Heart Study, a cardiovascular cohort study involving residents of the town of Framingham, Massachusetts, USA, which started in 1948 and continues to this day. Initially the study had about 5000 participants, at present the research team is studying the third generation of contributors. Since its inception, this amazing project has generated over 1000 publication. Framingham Heart Study data was crucial in establishing the links between ischaemic heart disease and smoking, hypertension, lack of exercise and obesity. The Framingham Risk Score based on features such as these predicts the 10-year risk of heart disease. Currently the study examines such questions as how genetic factors modify the risk of heart disease.
My editor’s choice from the current volume of Seizure is a paper by Maria Stefanidou et al. in which the authors use data from the Framingham Heart Study to find out more about the risk of epileptic seizures after an ischaemic stroke . We learn that about 5% of these patients experienced a seizure after their stroke. Seizures were similarly likely after large artery atherosclerosis and cardio-embolic strokes. Seizures were not observed after lacunar strokes, typically not involving cortical grey matter. Seizures occurred within the first 24 hours of the stroke in one third of participants and in one half in the first 30 days after the event. Seizures were more likely after more severe strokes.
At this stage, there is not enough data to allow clinicians to identify patients at such a high risk of post stroke seizures that antiepileptic drugs should be used prophylactically. However, the Framingham Heart Study is ongoing, so one day there may be a reliable Framingham Seizure Risk Score.
(1) Mahmood L, Vasan W. The Framingham Heart Study and the epidemiology of cardiovascular disease: a historical perspective. Lancet 2013; 383: 999–1008.
(2) Stefanidou M, Das RR, Beiser AS, Sundar B, Kelly- Hayes M, Kase CS, Devinsky O, Seshadri S, Freidman D. Incidence of seizures following initial ischemic stroke in a community-based cohort: The Framingham Heart Study. Seizure 2017; 47, 105-110