135. Evaluation of a Pharmacy-Driven Vancomycin Protocol and Predictors of Supratherapeutic Vancomycin Troughs
Session: Poster Abstract Session: Antimicrobial Stewardship: Adverse Drug Events
Thursday, October 8, 2015
Room: Poster Hall
Posters
  • 135_IDWPOSTER.pdf (154.4 kB)
  • Background:

    Previous studies show when pharmacists, compared to providers, dose vancomycin there is a higher proportion of troughs in goal range. The purpose of this study was to determine if two different pharmacist-driven protocols, compared to provider dosing, had an impact on vancomycin trough levels and to evaluate risk factors for supratherapeutic troughs.

    Methods:

    This retrospective cohort study compared adult patients who received ≥1 dose of vancomycin by one of three dosing strategies: provider-determined (Pr) 8/2012 - 2/2013, initial pharmacy protocol (IPh) 2/2013 - 7/2013, or revised pharmacy protocol with a more specific dosing table (RPh) 7/2014 - 1/2015. Patients were excluded if they received vancomycin for prophylaxis. Outcomes included percent of therapeutic (10-20 mg/L), subtherapeutic (<10 mg/L), supratherapeutic troughs (>20 mg/L); number of levels per patient; and percent of patients who had serum creatinine (Cr) increase by ≥0.3 mg/dL. Using the RPh group, logistic regression was used to identify predictors of supratherapeutic troughs.

     Results:

    330 patients received vancomycin by Pr, 468 by IPh, and 166 by RPh. Baseline weight, age, and creatinine clearance (CrCl) of patients were similar. There were no significant differences in proportion of therapeutic, subtherapeutic, or supratherapeutic troughs or in increases in Cr. However, fewer troughs per patient were obtained with IPh and RPh (2.5, 1.8, 1.8, p=.009).

    144 patients in the RPh group had a trough obtained and 41 were >25 mg/L. Q8H dosing and Cr rise ≥0.3 mg/dL were independent risk factors for troughs >25 mg/L (Table).

     Conclusion:

    Compared to provider dosing, pharmacy-driven protocols had similar vancomycin troughs while obtaining fewer troughs per patient. Q8H dosing and rise in Cr are risk factors for supratherapeutic troughs and should prompt careful use of Q8H dosing and close monitoring of levels in patients with rising Cr.

    Table. Risk factors for vancomycin troughs >25 mg/L

     

     

    Univariate

     

    Multivariate

    Variable

     

    No (N=103)

    n (%)

    Yes (N=41)

    n (%)

    p-value

     

    OR

    95% CI

    Weight > 100 kg

     

    16 (16)

    10 (24)

    .21

     

    2.0

    0.7-5.4

    ICU

     

    34 (33)

    20 (49)

    .07

     

     

     

    Protocol non-adherence

     

    19 (18)

    16 (39)

    .009

     

    2.2

    0.9-5.5

    Q8H dosing

     

    21 (20)

    20 (50)

    .0004

     

    4.2

    1.8-10.2

    ≥ 4 g/day

     

    12 (12)

    14 (35)

    .001

     

     

     

    Cr rise ≥ 0.3 mg/dL

     

    11 (11)

    15 (37)

    .0003

     

    6.0

    2.2-16.2

     

     

     

     

     

     

     

     

    Kati Shihadeh, PharmD, Acute Care Pharmacy, Denver Health Medical Center, Denver, CO, Bryan Knepper, MPH, MSc, CIC, Patient Safety and Quality, Denver Health Medical Center, Denver, CO, Heather Young, MD, Infectious Diseases, Denver Health Medical Center, Denver, CO and Timothy Jenkins, MD, Medicine/Infectious Diseases, University of Colorado-Denver Health Sciences Center, Denver, CO

    Disclosures:

    K. Shihadeh, None

    B. Knepper, None

    H. Young, None

    T. Jenkins, None

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 7th with the exception of research findings presented at the IDWeek press conferences.