title: Association between inappropriate empirical antimicrobial therapy and hospital length of stay in Gram-negative bloodstream infections: stratification by prognosis.
abstract: The potential benefit from appropriate empirical antimicrobial therapy in patients with favourable prognosis at initial presentation with Gram-negative bloodstream infection (BSI) remains unclear. This retrospective cohort study examined the impact of inappropriate empirical antimicrobial therapy on hospital length of stay (HLOS) following Gram-negative BSI after stratification by predicted prognosis using the BSI mortality risk score (BSIMRS).
  
  
  
  Hospitalized adults with first episodes of Gram-negative BSI from 1 January 2010 to 31 December 2013 at Palmetto Health Hospitals in Columbia, SC, USA were identified. Multivariate Cox proportional hazards regression was used to examine the association between inappropriate empirical antimicrobial therapy and HLOS overall and within each predefined BSIMRS category (<5 and ≥5).
  
  
  
  Among 830 unique patients with Gram-negative BSI, 469 and 361 had BSIMRS <5 and ≥5, respectively. Overall, the median age was 65 years, 448 (54%) were women, Escherichia coli (444; 53%) was the most common bloodstream isolate and 444 (53%) had a urinary source of infection. After adjustments in the multivariate model, BSIMRS (HR = 1.14 per point, 95% CI = 1.11-1.17, P < 0.001) and inappropriate empirical antimicrobial therapy (HR = 1.41, 95% CI = 1.07-1.91, P = 0.01) were independently associated with increased risk of remaining hospitalized following Gram-negative BSI. Median HLOS with appropriate and inappropriate empirical antimicrobial therapy was 7 and 10 days, respectively, in patients with BSIMRS <5 (P = 0.03) and 13 and 17 days, respectively, in those with BSIMRS ≥5 (P = 0.02).
  
  
  
  Inappropriate empirical antimicrobial therapy is associated with prolonged HLOS following Gram-negative BSI in patients with both good and guarded prognosis.
authors.affiliation: University of South Carolina School of Medicine, Columbia, SC, USA secain@g.clemson.edu.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Battle
authors.affiliation: Department of Clinical Pharmacy and Outcomes Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC, USA.|Department of Pharmacy, Palmetto Health Richland, Columbia, SC, USA.
authors.forename: P Brandon
authors.initials: PB
authors.lastname: Bookstaver
authors.affiliation: Department of Clinical Pharmacy and Outcomes Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC, USA.|Department of Pharmacy, Palmetto Health Richland, Columbia, SC, USA.
authors.forename: Julie Ann
authors.initials: JA
authors.lastname: Justo
authors.affiliation: Department of Pharmacy, Palmetto Health Richland, Columbia, SC, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Kohn
authors.affiliation: University of South Carolina School of Medicine, Columbia, SC, USA.|Department of Medicine, Division of Infectious Diseases, University of South Carolina School of Medicine, Columbia, SC, USA.
authors.forename: Helmut
authors.initials: H
authors.lastname: Albrecht
authors.affiliation: Department of Medicine, Division of Infectious Diseases, University of South Carolina School of Medicine, Columbia, SC, USA.
authors.forename: Majdi N
authors.initials: MN
authors.lastname: Al-Hasan
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use*; D016470:Bacteremia / Q000188:drug therapy*; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy*; D006761:Hospitals; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013022:South Carolina
chemical_list: D000900:Anti-Bacterial Agents