title: Plenty of pills: polypharmacy prevails in patients of a Danish anticoagulant clinic.
abstract: OBJECTIVE
  Vitamin K antagonist (VKA) treatment can successfully prevent thromboembolic complications, but the modality has a narrow therapeutic window and numerous interactions with other pharmaceuticals. The aim of the study reported here was to describe the use of co-medications and the prevalence of polypharmacy among patients treated with VKA.
  
  
  METHODS
  In a cross-sectional study, 250 consecutive patients (65% male, median age 68 years, most common indication for VKA treatment: atrial fibrillation) in the maintenance phase of VKA treatment were interviewed about their use of prescription medications, over-the-counter drugs and alternative medicines during the last 7 days.
  
  
  RESULTS
  The interviewed patients used a median of five medications (range 1-13), including VKA. Approximately 50% of the patients also took alternative medicines. A wide range of conventional and alternative medicines were used, several of which harbour possible interactions with VKA. Polypharmacy was defined as the use of five or more medications, excluding alternative medicines. The group of polypharmacy patients included 53% of the study population. The use of amiodarone, age >50 years, the indication for VKA treatment being atrial fibrillation or mechanical heart valves and diabetes were independent predictors of polypharmacy.
  
  
  CONCLUSIONS
  The results of this study highlight that polypharmacy is a common phenomenon among patients on anticoagulant medication, particularly among elderly patients or those suffering from cardiovascular disease or diabetes.
authors.affiliation: Unit for Thrombosis Research, Institute of Public Health, The University of Southern Denmark, c/o Department of Clinical Biochemistry, Hospital of South West Denmark, Finsensgade 35, DK-6700 Esbjerg, Denmark. jskov@health.sdu.dk
authors.forename: Jane
authors.initials: J
authors.lastname: Skov
authors.forename: Else-Marie
authors.initials: EM
authors.lastname: Bladbjerg
authors.forename: Johannes
authors.initials: J
authors.lastname: Sidelmann
authors.forename: Marianne
authors.initials: M
authors.lastname: Vamosi
authors.forename: Jørgen
authors.initials: J
authors.lastname: Jespersen
mesh_terms: D000368:Aged; D000554:Ambulatory Care Facilities; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000453:epidemiology; D000529:Complementary Therapies / Q000706:statistics & numerical data; D003430:Cross-Sectional Studies; D003718:Denmark; D004347:Drug Interactions; D017723:Drug Utilization Review / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D004366:Nonprescription Drugs / Q000008:administration & dosage / Q000627:therapeutic use; D019338:Polypharmacy; D011795:Surveys and Questionnaires; D014812:Vitamin K / Q000037:antagonists & inhibitors*
chemical_list: D000925:Anticoagulants; D004366:Nonprescription Drugs; D014812:Vitamin K