title: Impact of an antimicrobial allergy label in the medical record on clinical outcomes in hospitalized patients.
abstract: OBJECTIVE
  To determine the impact of having an antimicrobial allergy label in the medical record on clinical outcomes in hospitalized patients.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Urban academic teaching hospital.
  
  
  METHODS
  A total of 11,872 adults admitted to nonsurgical patient care wards who received at least one antimicrobial between August 1, 2007, and July 31, 2008; of these patients, 1324 (11.2%) had an antimicrobial allergy label and 10,548 (88.8%) did not have an allergy label documented in the medical record.
  
  
  RESULTS
  The following clinical outcomes were compared in patients with allergy labels versus patients without allergy labels: length of stay, admission to the intensive care unit (ICU), number of antimicrobials received during hospitalization, readmission within 4 weeks of hospital discharge, and death during hospitalization. Presence of an allergy label in the medical record was associated with increased length of stay, a higher ICU admission rate, receipt of more than one antimicrobial, and a higher mortality rate during the hospitalization. Logistic regression models were used to assess the association of allergy label with these outcomes while adjusting for covariates (age group, sex, surgery during hospitalization, and season of admission); multiple regression was used to model the association of allergy label with length of stay. On average, length of stay was 1.21 days (unadjusted) and 1.16 days (adjusted for covariates) longer in patients with allergy labels. The likelihood of an ICU admission were 1.4 times (adjusted odds ratio [OR] 1.42, 95% confidence interval [CI] 1.21-1.67) higher in patients with allergy labels. Presence of an allergy label was also associated with receipt of more than one antibiotic during the hospitalization (crude OR 1.61, 95% CI 1.43-1.81) and a 1.6-fold higher risk of dying during the hospitalization (crude OR 1.56, 95% CI 1.20-2.04). Presence of an allergy label was not associated with an increased risk of readmission within 4 weeks of discharge (adjusted OR 0.71, 95% CI 0.63-0.80).
  
  
  CONCLUSIONS
  Presence of an allergy label in the medical record was associated with increased length of hospital stay and worse clinical outcomes compared with no allergy label in hospitalized patients treated with antimicrobials.
authors.affiliation: Department of Pharmacy Practice and Science, University of Maryland School of Pharmacy, Rockville, 20850, USA. lcharnes@rx.umaryland.edu
authors.forename: Lisa
authors.initials: L
authors.lastname: Charneski
authors.forename: Gaurav
authors.initials: G
authors.lastname: Deshpande
authors.forename: Sheila Weiss
authors.initials: SW
authors.lastname: Smith
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000009:adverse effects* / Q000276:immunology; D015331:Cohort Studies; D004282:Documentation; D004342:Drug Hypersensitivity / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006784:Hospitals, Teaching / Q000706:statistics & numerical data; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data; D007902:Length of Stay / Q000706:statistics & numerical data; D016015:Logistic Models; D008297:Male; D008499:Medical Records / Q000706:statistics & numerical data*; D008875:Middle Aged; D010359:Patient Readmission / Q000706:statistics & numerical data; D012044:Regression Analysis; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents