984. Potential Benchmarks for Empiric Antibiotic (ABX) De-escalation: Frequency at a tertiary care medical center with an established antimicrobial stewardship program (ASP)
Session: Poster Abstract Session: Stewardship: Implementing Programs
Friday, October 4, 2013
Room: The Moscone Center: Poster Hall C
  • Liu IDSA 2013 Poster.png (357.2 kB)
  • Background:

    The promotion of ABX de-escalation is a key function of an ASP. The frequency with which ABX de-escalation occurs is not well described. The aim of this study is to measure the frequency of ABX de-escalation in hospitalized adults in an academic medical center with an established ASP. 


    Setting: 885-bed tertiary care center with an established ASP that promotes ABX de-escalation as a component of patient care.  Subjects: inpatients who received the combination of piperacillin-tazobactam and vancomycin for any indication during 2011, randomly selected and stratified by month. Electronic medical records were retrospectively reviewed for patient characteristics; ABX regimen, duration and indication; culture results; length of stay; and in-hospital mortality. The proportion of patients de-escalated by 24, 48, 72 and 96 hours was calculated. Subjects dying within 96 hours were considered not de-escalated for subsequent analysis, and were subtracted from the study population to determine an adjusted mortality. De-escalation was defined as ABX discontinuation or substitution of narrower spectrum ABX.


    The most common documented indications for piperacillin-tazobactam plus vancomycin therapy were pneumonia and sepsis. The proportion of patients de-escalated for each time point is shown in the Table. There was not a significant difference in frequency of de-escalation by service. 98% of patients had cultures obtained at the initiation of empiric ABX, 40% were positive. Patients with positive and negative cultures were similarly de-escalated, 71% and 72% respectively. Median length of stay was 5 days shorter in de-escalated patients, and the difference in adjusted mortality was not significant (p=0.82).

    Number (%) de-escalated by service

    Time (hours)

    Total (n=240)

    Critical Care (n=58)

    Oncology (n=21)

    Other (n=161)


    90 (38)

    28 (48)

    5 (24)

    57 (35)


    136 (57)

    31 (53)

    9 (43)

    96 (60)


    151 (63)

    36 (62)

    15 (71)

    100 (62)


    175 (73)

    40 (69)

    17 (81)

    118 (73)


    Approximately 70% of patients started on empiric ABX therapy were de-escalated in this medical center with an established ASP. Further data is needed, including studies assessing antibiotic appropriateness and outcomes, to determine benchmarks for ABX de-escalation.

    Peter Liu, MD1, Christopher Ohl, MD2, James Johnson, PharmD3, John Williamson, PharmD3, James Beardsley, PharmD3 and Vera Luther, MD2, (1)Wake Forest School of Medicine, Winston Salem, NC, (2)IM-Section On Infectious Diseases, Wake Forest School of Medicine, Winston-Salem, NC, (3)Wake Forest Baptist Health, Winston-Salem, NC


    P. Liu, None

    C. Ohl, None

    J. Johnson, None

    J. Williamson, None

    J. Beardsley, None

    V. Luther, None

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