title: Antiepileptic drug use in seven electronic health record databases in Europe: a methodologic comparison.
abstract: OBJECTIVE
  The annual prevalence of antiepileptic drug (AED) prescribing reported in the literature differs considerably among European countries due to use of different type of data sources, time periods, population distribution, and methodologic differences. This study aimed to measure prevalence of AED prescribing across seven European routine health care databases in Spain, Denmark, The Netherlands, the United Kingdom, and Germany using a standardized methodology and to investigate sources of variation.
  
  
  METHODS
  Analyses on the annual prevalence of AEDs were stratified by sex, age, and AED. Overall prevalences were standardized to the European 2008 reference population.
  
  
  RESULTS
  Prevalence of any AED varied from 88 per 10,000 persons (The Netherlands) to 144 per 10,000 in Spain and Denmark in 2001. In all databases, prevalence increased linearly: from 6% in Denmark to 15% in Spain each year since 2001. This increase could be attributed entirely to an increase in "new," recently marketed AEDs while prevalence of AEDs that have been available since the mid-1990s, hardly changed. AED use increased with age for both female and male patients up to the ages of 80 to 89 years old and tended to be somewhat higher in female than in male patients between the ages of 40 and 70. No differences between databases in the number of AEDs used simultaneously by a patient were found.
  
  
  CONCLUSIONS
  We showed that during the study period of 2001-2009, AED prescribing increased in five European Union (EU) countries and that this increase was due entirely to the newer AEDs marketed since the 1990s. Using a standardized methodology, we showed consistent trends across databases and countries over time. Differences in age and sex distribution explained only part of the variation between countries. Therefore, remaining variation in AED use must originate from other differences in national health care systems.
authors.affiliation: Division of Pharmacoepidemiology & Clinical Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.
authors.forename: Mark C H
authors.initials: MCH
authors.lastname: de Groot
authors.affiliation: Epidemiology, Patient-Reported Outcomes, and Healthcare Data Strategy, F. Hoffmann-La Roche, Basel, Switzerland.
authors.forename: Markus
authors.initials: M
authors.lastname: Schuerch
authors.affiliation: Division of Pharmacoepidemiology & Clinical Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.|Department of Clinical Pharmacy and Toxicology, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: Frank
authors.initials: F
authors.lastname: de Vries
authors.affiliation: National Institute for Health Data and Disease Control, Copenhagen, Denmark.
authors.forename: Ulrik
authors.initials: U
authors.lastname: Hesse
authors.affiliation: Agencia Española de Medicamentos y Productos Sanitarios, Madrid, Spain.
authors.forename: Belén
authors.initials: B
authors.lastname: Oliva
authors.affiliation: Agencia Española de Medicamentos y Productos Sanitarios, Madrid, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Gil
authors.affiliation: Agencia Española de Medicamentos y Productos Sanitarios, Madrid, Spain.
authors.forename: Consuelo
authors.initials: C
authors.lastname: Huerta
authors.affiliation: Pharmacology Section, Department of Biomedical Sciences II, University of Alcalá, Madrid, Spain.
authors.forename: Gema
authors.initials: G
authors.lastname: Requena
authors.affiliation: Pharmacology Section, Department of Biomedical Sciences II, University of Alcalá, Madrid, Spain.|Clinical Pharmacology Unit, University Hospital Príncipe de Asturias, Madrid, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: de Abajo
authors.affiliation: Division of Pharmacoepidemiology & Clinical Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.
authors.forename: Ana S
authors.initials: AS
authors.lastname: Afonso
authors.affiliation: Division of Pharmacoepidemiology & Clinical Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Souverein
authors.affiliation: European Medicines Agency, London, United Kingdom.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Alvarez
authors.affiliation: European Medicines Agency, London, United Kingdom.
authors.forename: Jim
authors.initials: J
authors.lastname: Slattery
authors.affiliation: Institute for Medical Information Sciences, Biometry, and Epidemiology, Ludwig-Maximilians-Universität-München, Munich, Germany.
authors.forename: Marietta
authors.initials: M
authors.lastname: Rottenkolber
authors.affiliation: Department of Clinical Pharmacology, Faculty of Health, School of Medicine, Witten/Herdecke University, Witten, Germany.|Philipp Klee-Institute for Clinical Pharmacology, Helios Clinic Wuppertal, Wuppertal, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Schmiedl
authors.affiliation: Division of Pharmacoepidemiology & Clinical Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.|NIVEL, Netherlands Institute for Health Services Research, Utrecht, The Netherlands.
authors.forename: Liset
authors.initials: L
authors.lastname: Van Dijk
authors.affiliation: Global Clinical Epidemiology, Novartis Pharma AG, Basel, Switzerland.
authors.forename: Raymond G
authors.initials: RG
authors.lastname: Schlienger
authors.affiliation: Epidemiology, Pfizer Inc., New York, New York, U.S.A.
authors.forename: Robert
authors.initials: R
authors.lastname: Reynolds
authors.affiliation: Division of Pharmacoepidemiology & Clinical Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.
authors.forename: Olaf H
authors.initials: OH
authors.lastname: Klungel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000927:Anticonvulsants / Q000627:therapeutic use*; D003431:Cross-Cultural Comparison; D016208:Databases, Factual; D017277:Drug Approval; D004363:Drug Utilization / Q000706:statistics & numerical data*; D057286:Electronic Health Records; D005060:Europe; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*
chemical_list: D000927:Anticonvulsants
keywords: Antiepileptic drug use; Drug safety; Epidemiology; Healthcare databases