title: [Systematic review of studies assessing the cost of adverse drug reactions].
abstract: OBJECTIVE
  Adverse drug reactions (ADRs) are an important healthcare problem. The objective of this study was to review published articles analyzing the cost of ADRs in any healthcare setting.
  
  
  METHODS
  We conducted a search of articles published on the cost of ADRs in the bibliographic databases from 1970 to 2010. We identified 28 studies and selected 16 that included cases of ADR fitting the World Health Organization's definition of these events. The information on the characteristics of the study design, the types of costs analyzed and the reported results were reviewed.
  
  
  RESULTS
  The design features and populations included in the studies were heterogeneous. Only two studies explicitly defined the perspective adopted. Only five studies compared cases of ADR with matched controls without ADRs. All studies analyzed direct healthcare costs, but none analyzed indirect or intangible costs. Fourteen publications analyzed the costs of length of hospital stay. The average (SD) percentage of ADRs was 3.04% (0.2) [median 2.4%, range 0.7% to 26.1%]. The median length of hospital stay in patients with ADRs was 8.8 days (range: 0.15 to 19.2 days). Accounting systems and monetary costs varied widely.
  
  
  CONCLUSIONS
  Studies on the costs of ADRs are highly heterogeneous and have evaluated direct healthcare costs in hospitals. Their results indicate that ADRs generate substantial costs. More studies using appropriate methodology are needed on the costs of ADRs.
authors.affiliation: Servicio de Farmacología Clínica, IDIBELL, Hospital Universitari de Bellvitge, Universitat de Barcelona, Barcelona, España. avallano@bellvitgehospital.cat
authors.forename: Antonio
authors.initials: A
authors.lastname: Vallano Ferraz
authors.forename: Antonia
authors.initials: A
authors.lastname: Agustí Escasany
authors.forename: Consuelo
authors.initials: C
authors.lastname: Pedrós Xolvi
authors.forename: Josep M
authors.initials: JM
authors.lastname: Arnau de Bolós
mesh_terms: D003365:Costs and Cost Analysis; D064420:Drug-Related Side Effects and Adverse Reactions / Q000191:economics*; D006801:Humans; D011795:Surveys and Questionnaires