title: Medicine-related problems resulting in emergency department visits.
abstract: OBJECTIVE
  Our aim was to estimate the prevalence of medicine-related problems, understood as negative clinical outcomes, that result in hospital emergency department (ED) visits and to establish relationships among risk factors and the appearance of pharmacotherapy negative outcomes.
  
  
  METHODS
  Methods A stratified two-stage probabilistic sampling approach was used which consisted of stratified random sampling of patients visiting the ED followed up by interviews. A systematic appraisal tool was used to identify pharmacotherapy negative outcomes within the framework of the information gathered. Bivariate and multivariate analyses were carried out. Cost per process was estimated.
  
  
  RESULTS
  The prevalence of pharmacotherapy negative outcomes producing ED visits was 33.17% (95%CI: 31.09-35.25). These negative outcomes could be divided into three categories: ineffectiveness (19.76%; 95%CI: 17.92-21.60), necessity/use (10.52%; 95%CI: 9.48-11.56), and lack of safety (2.89%). About 73% (95%IC: 70.03-76.23) of the negative outcomes were considered to be preventable. Average cost per negative outcome was 329.5 euros (95%CI: 185.4-473.5). Factors associated with the appearance of negative outcomes were age, number of medicines taken, and the combined effect of both of these factors. Compared with those participants younger than 18 years, patients between 45 and 64 years of age presented an odds ratio (OR) of 2.52 (95%CI: 1.1-5.78), while those older than 65 years had an OR of 3.63 (95%CI: 1.27-10.35). Compared with people not using medicine(s), patients using one to two different medicines presented with an OR = 19.91 (95%CI: 8.28-47.87), and those using more than three medicines had an OR = 22.71 (95%CI: 3.05-69.26). Finally, compared with patients younger than 18 years and not using medicines, patients aged 45-64 years taking three or more different medicines presented with an OR = 64.07, while those older than 65 years taking three or more medicines presented with an OR = 31.50.
  
  
  CONCLUSIONS
  The prevalence of negative clinical outcomes was 33%, of which more than 73% of these were preventable. Factors associated with their appearance were age, number of medicines, and their combined effect.
authors.affiliation: Pharmaceutical Care Research Group, University of Granada, Granada, Spain. f_llimos@medynet.com
authors.forename: M Isabel
authors.initials: MI
authors.lastname: Baena
authors.forename: M Jose
authors.initials: MJ
authors.lastname: Faus
authors.forename: Paloma C
authors.initials: PC
authors.lastname: Fajardo
authors.forename: Francisco M
authors.initials: FM
authors.lastname: Luque
authors.forename: Francisco
authors.initials: F
authors.lastname: Sierra
authors.forename: Jose
authors.initials: J
authors.lastname: Martinez-Olmos
authors.forename: Andres
authors.initials: A
authors.lastname: Cabrera
authors.forename: Fernando
authors.initials: F
authors.lastname: Fernandez-Llimos
authors.forename: Fernando
authors.initials: F
authors.lastname: Martinez-Martinez
authors.forename: José
authors.initials: J
authors.lastname: Jiménez
authors.forename: Antonio
authors.initials: A
authors.lastname: Zarzuelo
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003365:Costs and Cost Analysis; D004347:Drug Interactions; D004358:Drug Therapy / Q000191:economics*; D064420:Drug-Related Side Effects and Adverse Reactions; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006785:Hospitals, University; D006801:Humans; D007223:Infant; D008508:Medication Errors; D008875:Middle Aged; D015233:Models, Statistical; D015999:Multivariate Analysis; D019338:Polypharmacy; D013030:Spain; D016896:Treatment Outcome