2065. How National Healthcare Safety Network (NHSN) Clostridium difficile (CD) Infection (I) Criteria Changes Affected the Hospital Acquired (HA) CDI rate at University Pittsburgh Medical Center (UPMC) and Comparison to Historic Baselines
Session: Poster Abstract Session: Clostridium difficile: Epidemiology
Saturday, October 29, 2016
Room: Poster Hall
  • abstr. ID Week 2016 CDI Overcapture Poster FINAL.PDF (727.7 kB)
  • Background: CD significantly impacts patient outcome and costs. Over the past 15 years many health-care facilities, including our 757 bed complex university hospital described CD outbreaks, many due to the introduction of the BI strain. In 2000, our hospital acquired (HA) CDI rate peaked at 17/10,000 patient-days. After implementing a comprehensive CD control bundle, the HA CDI rate fell below the pre-outbreak rate and has been sustained since. Rates have always been calculated using NHSN definition gastroenteritis (GE) definition (CD1). Criteria included at least one signs or symptom in addition to a positive lab or pathology diagnostic test.  In 1/15 NHSN added a CDI category (CD2) defined as a + test for toxin-producing CD difficile on an unformed stool specimen or evidence of pseudomembranous colitis on gross anatomic or histopathologic exam after hospital day (HD) 2 and include repeat infection timeframe (RIT) and no longer required presence of signs and symptoms. Our objective was to evaluate the effect of the CDI definition change on house-wide HA CDI rates.

    Methods:  HA CDI data was calculated over 2 time periods (TP). During TP 1 CD1 was used. During TP 2 both the CD1 & CD2 definitions were used and data was compared.




    HA CDI rates increased from a mean rate of 6.68 in TP 1 to 13.1 in TP 2 (Rate Ratio 3.0, CI 2.7-3.3, p = 1 X 10-7).



    ·         Recent NHSN HA CDI definition change has resulted in a significant increase in CDIs deemed HA.

    ·         Additional CD is now deemed HA include:

    o   Asymptomatic CD carriers

    o   Patients with CDI symptoms present on admission but not lab defined until after HD2,

    o   Recaptures patients with CDI that last >14 days (RIT rule).

    ·         In part, these additional CDIs may not represent true infection and/or hospital acquisition and so it will become difficult to assess patient safety efforts

    ·         CDI bundle prevention measures will only reduce true infections and so perfecting prevention methods may not be reflected in reduced CDI rates.

    ·         NHSN should reconsider this new CDI definition as was done for catheter –associated UTIs.





    Carlene Muto, MD, MS, FSHEA1, Amy Metzger, BS, MT (ASCP), CIC, CHI2 and Ashley Querry, BS, CIC2, (1)Infection Prevention & Hospital Epidemiology, University of Pittsburgh Medical Center, Presbyterian University Hospital, Pittsburgh, PA, (2)Infection Prevention and Control, University of Pittsburgh Medical Center Presbyterian, Pittsburgh, PA


    C. Muto, None

    A. Metzger, None

    A. Querry, None

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