title: Medication regimen complexity and hospital readmission for an adverse drug event.
abstract: BACKGROUND
  Adverse drug events (ADEs) are costly, dangerous, and often preventable. Little is known about the link between medication regimen complexity and rehospitalization as a result of an ADE.
  
  
  OBJECTIVE
  The objective of this study was to compare admission and discharge medication regimen complexity in 2 cohorts: patients readmitted for an ADE within 30 days and patients not readmitted for an ADE.
  
  
  METHODS
  The study used a retrospective parallel-group case-control design. Participants from 4 urban acute care hospitals were included in the revisit cohort if they were rehospitalized within 30 days as a result of an adverse event coded as accidental poisoning. The no-revisit cohort was formed by randomly sampling patients with the same disease classification codes as the revisit group but without history of a readmission within 30 days. Complexity of medication regimens at the initial admission and discharge was quantified with the medication regimen complexity index (MRCI).
  
  
  RESULTS
  The revisit group comprised 92 individuals and the no-revisit group, 228. The revisit group had a significantly higher MRCI score at admission and discharge than the no-revisit group (all P < .005). Receiver operating characteristic curves, used to determine a potential MRCI cutoff score for risk of an ADE, revealed MRCI scores of 8 or greater to optimally predict increased risk for readmission caused by an ADE.
  
  
  CONCLUSIONS
  Complex medication regimens at hospital admission are predictive of rehospitalizations for ADEs. This finding suggests that medication regimen complexity be considered as a target for interventions to decrease the risk for readmission.
authors.affiliation: Washington State University, Spokane, WA, USA.
authors.forename: Megan N
authors.initials: MN
authors.lastname: Willson
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Greer
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Weeks
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D004363:Drug Utilization / Q000706:statistics & numerical data; D064420:Drug-Related Side Effects and Adverse Reactions / Q000453:epidemiology*; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D008875:Middle Aged; D010351:Patient Discharge / Q000706:statistics & numerical data; D010359:Patient Readmission / Q000706:statistics & numerical data*
keywords: acute care; adverse drug event; hospital readmission; medication regimen complexity