title: Outcomes of emergency department patients presenting with adverse drug events.
abstract: OBJECTIVE
  Our objectives are to describe the outcomes of patients presenting to the emergency department (ED) because of an adverse drug event and to compare them with outcomes of patients presenting for other reasons.
  
  
  METHODS
  This prospective observational study was conducted at Vancouver General Hospital, a 955-bed tertiary care hospital. We prospectively enrolled adults presenting to the ED between March and June 2006, using a systematic sampling algorithm. Pharmacists and physicians independently evaluated patients for adverse drug events. An independent committee reviewed and adjudicated cases in which assessments were discordant or uncertain. Data from the index visit were linked to vital statistics, administrative health services utilization, and cost of care data.
  
  
  RESULTS
  Of 1,000 patients, 122 (12.2%; 95% confidence interval [CI] 10.3% to 14.4%) presented to the ED because of an adverse drug event. Of these, 48 presented because of an adverse drug reaction (one type of adverse drug event defined as an unintended response that occurred despite use of an appropriate drug dosage). We found no difference in mortality among patients presenting with and without adverse drug reactions (14.6% versus 5.9%; hazard ratio 1.57; 95% CI 0.70 to 3.52). After adjustment, patients with adverse drug events had a higher risk of spending additional days in the hospital per month (6.3% versus 3.4%; odds ratio 1.52; 95% CI 1.43 to 1.62) and higher rate of outpatient health care encounters (1.73 versus 1.22; rate ratio 1.20; 95% CI 1.03 to 1.40). The adjusted median monthly cost of care was 1.90 times higher (Can $325 versus $96; 95% CI 1.18 to 3.08).
  
  
  CONCLUSIONS
  ED patients presenting with an adverse drug event incurred greater health services utilization and costs during a 6-month follow-up period compared with patients presenting for other reasons.
authors.affiliation: Department of Emergency Medicine, University of British Columbia, Vancouver, Canada. chohl@interchange.ubc.ca
authors.forename: Corinne M
authors.initials: CM
authors.lastname: Hohl
authors.forename: Bohdan
authors.initials: B
authors.lastname: Nosyk
authors.forename: Lisa
authors.initials: L
authors.lastname: Kuramoto
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Zed
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Brubacher
authors.forename: Riyad B
authors.initials: RB
authors.lastname: Abu-Laban
authors.forename: Samuel B
authors.initials: SB
authors.lastname: Sheps
authors.forename: Boris
authors.initials: B
authors.lastname: Sobolev
mesh_terms: D000465:Algorithms; D016001:Confidence Intervals; D004636:Emergency Service, Hospital / Q000191:economics / Q000706:statistics & numerical data*; D005260:Female; D017048:Health Care Costs / Q000706:statistics & numerical data; D017721:Hospital Costs / Q000706:statistics & numerical data; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D016015:Logistic Models; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D016017:Odds Ratio; D017063:Outcome Assessment, Health Care; D055553:Prescription Drugs / Q000009:adverse effects*; D016016:Proportional Hazards Models; D011446:Prospective Studies
chemical_list: D055553:Prescription Drugs