1788. Cost-Effectiveness of Penicillin Skin Testing among Patients with Methicillin Sensitive Staphylococcus aureus bacteremia and Reported Penicillin Allergy
Session: Poster Abstract Session: Antimicrobial Stewardship: Impact of Allergy
Saturday, October 6, 2018
Room: S Poster Hall
Posters
  • IDWeek MSSA PCN CEA_.pdf (692.6 kB)
  • Background:

    Methicillin sensitive Staphylococcus aureus (MSSA) bacteremia is a highly lethal infection; first-line therapy with a beta-lactam, commonly cefazolin, provides a significant mortality benefit over the second-line therapy, vancomycin, which is often used in patients reporting beta-lactam allergy.

    Methods:

    We designed a simulation model of inpatients aged 55-75 years with MSSA bacteremia and a self-reported history of beta-lactam allergy. The model adopted a U.S. health-system perspective, a lifetime horizon, and a willingness-to-pay threshold of $100,000 per quality-adjusted life year (QALY). We compared routine care (vancomycin), history screening (questionnaire assessing anaphylaxis history), and bedside penicillin skin testing. Incremental cost-effectiveness ratio (ICER) was measured using 2017 US dollars per QALY. Baseline co-morbid states (diabetes, malignancy, and end-stage renal disease (ESRD) requiring dialysis) were also modeled. Future costs and benefits were discounted at 3% per year.

    Results:

    Among patients with MSSA bacteremia and a self-reported penicillin allergy, skin testing produced the best clinical outcomes and was cost-effective relative to history screening, generating 0.51 additional QALYs at an ICER of $22,062 per QALY gained. Among patients with diabetes, malignancy, or ESRD, the ICER for skin testing relative to history screening increased to $30,830-$127,182, reflecting the overall lower life expectancy and high annual survivor healthcare cost in these higher-risk groups. Results were robust to wide variations in the cost and diagnostic performance of skin testing: in sensitivity analyses, skin testing remained the optimal strategy when cost was <$5600, specificity >60%, and sensitivity >10%.

    Conclusion:

    Among adults with MSSA bacteremia and a self-reported beta-lactam allergy, skin testing is cost effective relative to history screening and routine care at conventional willingness-to-pay thresholds and should be widely adopted given the mortality benefit of beta-lactams over alternate antibiotics in MSSA bacteremia.

    Alon Vaisman, MD, Medicine, University of Toronto, Toronto, ON, Canada, Henry F. Chambers, MD, Clinical Research Services, University of California San Francisco, Clinical and Translational Sciences Institute, San Francisco, CA, Lisa G. Winston, MD, Medicine, University of California, San Francisco and Zuckerberg San Francisco General Hospital and Trauma Center, San Francisco, CA and Dhruv Kazi, MD, MSc, MS, Medicine, Zuckerberg San Francisco General Hospital, San Francisco, CA

    Disclosures:

    A. Vaisman, None

    H. F. Chambers, None

    L. G. Winston, None

    D. Kazi, None

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 3rd with the exception of research findings presented at the IDWeek press conferences.