title: Hospital re-admission associated with adverse drug reactions in patients over the age of 65 years.
abstract: BACKGROUND
  Adverse drug reactions (ADRs) are responsible for 5 % of hospital admissions, but hospital re-admission induced by ADRs remains poorly documented.
  
  
  OBJECTIVE
  The aim of this study was to estimate the rate of hospital re-admission and the factors associated with re-admission in the patients over the age of 65 years. Secondary, we described the characteristics of cases of ADRs leading to re-admission for drugs other than chemotherapy agents.
  
  
  METHODS
  Data were extracted from hospital discharge summaries provided by the Department of Medical Information of Toulouse University Hospital. All patients over the age of 65 years admitted to the hospital in 2010 for an ADR, identified from ICD-10 codes, were selected. All subsequent admissions of members of this cohort within 1 year of discharge following the index admission were reviewed retrospectively. The risk factors associated with hospital re-admission for ADRs were analyzed. Medical records were used for descriptive analysis of re-admission due to drugs other than chemotherapy agents.
  
  
  RESULTS
  We found that 553 of the 1000 patients admitted for ADRs in 2010 were re-admitted to hospital within 1 year. Among them, 87 cases were re-admitted for ADRs (estimated rate of 87/1000 re-admission for an ADR within 1 year). A comparison of the patients re-admitted for ADRs (n = 87) with those of patients re-admitted for other causes (n = 410) suggested that only cancer increased the risk of re-admission for ADRs (OR = 7.69 [4.59-12.88] 95 % CI). ADRs due to the same drug combination were the suspected cause of repeat admission in half the cases (other than chemotherapy). Hospital re-admission was considered avoidable in four cases (22 %).
  
  
  CONCLUSIONS
  This study shows an estimated rate of re-admission for an ADR around 87/1000 within 1 year, and the same drug combination were the suspected cause of repeat admission in half the cases. At least, 11 % of cases were avoidable.
authors.affiliation: Service de Pharmacologie Médicale et Clinique, Centre Midi-Pyrénées de Pharmacovigilance, de Pharmacoépidémiologie et d'Informations sur le Médicament, Faculté de Médecine de l'Université Paul Sabatier-, INSERM U1027, 37 Allées Jules Guesde, 31000, Toulouse, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Hauviller
authors.affiliation: Service de Pharmacologie Médicale et Clinique, Centre Midi-Pyrénées de Pharmacovigilance, de Pharmacoépidémiologie et d'Informations sur le Médicament, Faculté de Médecine de l'Université Paul Sabatier-, INSERM U1027, 37 Allées Jules Guesde, 31000, Toulouse, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Eyvrard
authors.affiliation: Département d'Informations Médicales, CHU Toulouse, Hôtel Dieu St Jacques, 2 Rue Viguerie, 31300, Toulouse, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Garnault
authors.affiliation: Service de Pharmacologie Médicale et Clinique, Centre Midi-Pyrénées de Pharmacovigilance, de Pharmacoépidémiologie et d'Informations sur le Médicament, Faculté de Médecine de l'Université Paul Sabatier-, INSERM U1027, 37 Allées Jules Guesde, 31000, Toulouse, France.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Rousseau
authors.affiliation: Département d'Informations Médicales, CHU Toulouse, Hôtel Dieu St Jacques, 2 Rue Viguerie, 31300, Toulouse, France.
authors.forename: L
authors.initials: L
authors.lastname: Molinier
authors.affiliation: Service de Pharmacologie Médicale et Clinique, Centre Midi-Pyrénées de Pharmacovigilance, de Pharmacoépidémiologie et d'Informations sur le Médicament, Faculté de Médecine de l'Université Paul Sabatier-, INSERM U1027, 37 Allées Jules Guesde, 31000, Toulouse, France.
authors.forename: Jean Louis
authors.initials: JL
authors.lastname: Montastruc
authors.affiliation: Service de Pharmacologie Médicale et Clinique, Centre Midi-Pyrénées de Pharmacovigilance, de Pharmacoépidémiologie et d'Informations sur le Médicament, Faculté de Médecine de l'Université Paul Sabatier-, INSERM U1027, 37 Allées Jules Guesde, 31000, Toulouse, France. haleh.bagheri@univ-tlse3.fr.
authors.forename: Haleh
authors.initials: H
authors.lastname: Bagheri
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D064420:Drug-Related Side Effects and Adverse Reactions / Q000453:epidemiology*; D005260:Female; D005602:France / Q000453:epidemiology; D006785:Hospitals, University / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D010359:Patient Readmission / Q000706:statistics & numerical data*; D012189:Retrospective Studies
keywords: Adverse drug reactions; Avoidability; Hospital re-admission; Pharmacovigilance