title: Hospitalisations caused by adverse drug reactions (ADR): a meta-analysis of observational studies.
abstract: OBJECTIVE
  To establish the percentage hospital admission related to adverse drug reactions (ADRs) from the data available in the literature.
  
  
  METHODS
  Literature search in the Medline database, meta-analysis.
  
  
  RESULTS
  From the literature it is revealed that a considerable part of all hospital admissions are related to adverse drug reactions. However, these data are not homogenous, i.e. larger studies display a lower percentage of ADR related hospital admission, while smaller studies display a higher percentage. Subgroup analysis showed that for elderly people the odds of being hospitalised by ADR related problems is 4 times higher than for younger ones (16.6% vs. 4.1%). A considerable part of these hospitalisations can be prevented. Subgroup analysis revealed that in the elderly up to 88% of the ADR related hospitalisations are preventable; for the non-elderly this is only 24%. Comparatively more elderly people are hospitalised than younger ones. Combining these findings, twice as much elderly people are hospitalised by ADR related problems than non-elderly, while preventability of ADR related hospitalisation might yield 7 times more people in the elderly than in the non-elderly. The estimation of the costs of ADR related hospitalisations in the Health Care system in The Netherlands is discussed.
  
  
  CONCLUSIONS
  Many elderly people are hospitalised by ADR related problems; an important part of these hospitalisations can be avoided.
authors.affiliation: Scientific Institute Dutch Pharmacists (WINAp), P.O. Box 30460, 2500 GL The Hague, The Netherlands. h.j.m.beijer@winap.nl
authors.forename: H J M
authors.initials: HJ
authors.lastname: Beijer
authors.forename: C J
authors.initials: CJ
authors.lastname: de Blaey
mesh_terms: D016907:Adverse Drug Reaction Reporting Systems / Q000706:statistics & numerical data; D000367:Age Factors; D000368:Aged; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D019370:Observation / Q000379:methods*