Epilepsy Research (2009) 87, 137—143 journal homepage: www.elsevier.com/locate/epilepsyres Prevalence of acute repetitive seizures (ARS) in the United Kingdom Carlos Martinez a , Tim Sullivan b , W. Allen Hauser c,* a Department of Medicine, Faculty of Medicine, McGill University, Montreal, Canada b AstraZeneca Pharmaceuticals, Wilmington, DE, USA c Department of Neurology and Epidemiology, College of Physicians and Surgeons and Mailman School of Public Health, Columbia University, New York, NY, USA Received 19 June 2008; received in revised form 1 June 2009; accepted 9 August 2009 Available online 11 September 2009 KEYWORDS Acute repetitive seizures; Incidence; Prevalence; Epilepsy; GRPD; Catastrophic epilepsies Summary Introduction: ‘‘Acute repetitive seizures’’ (ARS) is a term to describe a condition manifest by multiple seizures occurring over a relatively brief period of time -generally 24 hours- in patients with epilepsy. There is limited information regarding the epidemiology of ARS in the general population. Methods: We performed a historical cohort study using data from the United Kingdom General Practice Research Database (GPRD) to identify all incident and prevalent cases of active epilepsy in 2005. From among this group, we identified individuals at risk for ARS. This included those with ‘‘catastrophic epilepsy syndromes of childhood’’ (CE), and those with a history of seizure clustering in the context of other epilepsy syndromes. Results: We identified 21,010 people with active epilepsy in the GPRD in 2005; prevalence 7.2/1000; age adjusted to the European Standard Population, 6.7; incidence 50/100,000 per year, age-adjusted 48/100,000. We identified 665 people at risk for ARS. The prevalence of CE in the general population was 1.2/10,000 and that of cluster seizures was 1.1/10,000. We estimated the crude prevalence of ARS in the general population to be 2.3/10,000; age adjusted 2.5 (CI, 2.3—2.7. The prevalence of ARS was highest in those 0—4 years of age (5.9/10,000) and fell with advancing age to 0.5/10,000 in those age 70 and older). Conclusions: This is the first population-based study to provide information on the prevalence of ARS. ARS affects about 3% of the population with epilepsy and 0.02% of the general population. More studies are needed to further evaluate this serious epilepsy phenomenon. © 2009 Elsevier B.V. All rights reserved. * Corresponding author at: 630 W 168th Street, New York, NY 10032, USA. Tel.: +1 212 305 2447. E-mail address: wahauser@optonline.net (W.A. Hauser). Introduction The terms ‘‘acute repetitive seizures’’ (ARS), ‘‘cluster seizures’’, ‘‘serial seizures’’, ‘‘flurry seizures’’, describe a condition characterized by multiple generalized tonic, 0920-1211/$ — see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.eplepsyres.2009.08.006