title: Seizures in patients with Alzheimer's disease or vascular dementia: a population-based nested case-control analysis.
abstract: OBJECTIVE
  Patients with Alzheimer's disease (AD) have an increased risk of developing seizures or epilepsy. Little is known about the role of risk factors and about the risk of developing seizures/epilepsy in patients with vascular dementia (VD). The aim of this study was to assess incidence rates (IRs) of seizures/epilepsy in patients with AD, VD, or without dementia, and to identify potential risk factors of seizures or epilepsy.
  
  
  METHODS
  We conducted a follow-up study with a nested case-control analysis using the United Kingdom-based General Practice Research Database (GPRD). We identified patients aged ≥65 years with an incident diagnosis of AD or VD between 1998 and 2008 and a matched comparison group of dementia-free patients. Conditional logistic regression was used to estimate the odds ratio (OR) with a 95% confidence interval (CI) of developing seizures/epilepsy in patients with AD or VD, stratified by age at onset and duration of dementia as well as by use of antidementia drugs.
  
  
  RESULTS
  Among 7,086 cases with AD, 4,438 with VD, and 11,524 matched dementia-free patients, we identified 180 cases with an incident diagnosis of seizures/epilepsy. The IRs of epilepsy/seizures for patients with AD or VD were 5.6/1,000 person-years (py) (95% CI 4.6-6.9) and 7.5/1,000 py (95% CI 5.7-9.7), respectively, and 0.8/1,000 py (95% CI 0.6-1.1) in the dementia-free group. In the nested case-control analysis, patients with longer standing (≥3 years) AD had a slightly higher risk of developing seizures or epilepsy than those with a shorter disease duration, whereas in patients with VD the contrary was observed.
  
  
  CONCLUSIONS
  Seizures or epilepsy were substantially more common in patients with AD and VD than in dementia-free patients. The role of disease duration as a risk factor for seizures/epilepsy seems to differ between AD and VD.
authors.affiliation: Basel Pharmacoepidemiology Unit, Division of Clinical Pharmacy and Epidemiology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland.
authors.forename: Patrick
authors.initials: P
authors.lastname: Imfeld
authors.forename: Michael
authors.initials: M
authors.lastname: Bodmer
authors.forename: Markus
authors.initials: M
authors.lastname: Schuerch
authors.forename: Susan S
authors.initials: SS
authors.lastname: Jick
authors.forename: Christoph R
authors.initials: CR
authors.lastname: Meier
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications* / Q000453:epidemiology*; D015992:Body Mass Index; D016022:Case-Control Studies; D015897:Comorbidity; D003627:Data Interpretation, Statistical; D016208:Databases, Factual; D015140:Dementia, Vascular / Q000150:complications* / Q000453:epidemiology*; D004827:Epilepsy / Q000453:epidemiology / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D058006:General Practice / Q000706:statistics & numerical data; D006801:Humans; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D011153:Population; D012306:Risk; D012307:Risk Factors; D012640:Seizures / Q000150:complications* / Q000453:epidemiology*; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology; D006113:United Kingdom / Q000453:epidemiology