C difficile Infection: The Battle Continues

Becky A. Smith, MD; Lance R. Peterson, MD


January 19, 2016

Editorial Collaboration

Medscape &

Clostridium difficile Infection Among Veterans Health Administration Patients

Young-Xu Y, Kuntz JL, Gerding DN, et al
Infect Control Hosp Epidemiol. 2015;36:1038-1045

Sensitive Test, Low Infection Rate

Two recent publications highlight the success of the national Veterans Health Administration (VHA) system in controlling Clostridium difficile infection (CDI) while using polymerase chain reaction (PCR) for diagnosis and the implication of disrupting the usual stool flora with vancomycin or metronidazole therapy for CDI.

In the first report, Young-Xu and colleagues performed a retrospective descriptive analysis of data extracted from the large VHA electronic health record database to assess the rate of CDI between 2009 and 2013. Two important changes occurred. The first was the earlier establishment of a VHA bundle for infection control,[1] and the second was the implementation of PCR testing for CDI. To detect CDI episodes, they used the International Classification of Diseases, ninth revision (ICD-9) diagnosis code for CDI (008.45) during an inpatient stay (discharge diagnosis) or outpatient encounter; a positive test result for C difficile toxins or toxin genes; or therapy with metronidazole or oral vancomycin in the 14 days before or after a Current Procedural Terminology (CPT)-4 code (87230, 87324, 87449, or 87803) for a C difficile test. The annual number of patients with at least one encounter rose from 5.4 million in 2009 to 5.9 million in 2013.

The rate of hospital-onset CDI rose from 6.2/10,000 patient-days in 2009 (the year PCR was introduced for diagnosis) to 7.2/10,000 in 2011 and then plateaued at 7.4/10,000 patient-days in 2012 and 2013. With the VHA mean length of stay being 5.2 days,[2] this translates to an increase from 3.2 cases/1000 admissions to 3.8 cases/1000 admissions during the study. Although it is difficult to estimate the national CDI disease rate, the US national burden of CDI was estimated to be 9.4 cases/1000 discharges in 2010,[3] a rate far exceeding that of the VHA throughout the period assessed. Moreover, in 2009 and 2010, the pooled rates of CDI in Illinois, Massachusetts, and New York were 9.3 and 7.5 cases/10,000 patient-days, respectively,[4] which was also higher than the VHA rate for those years. The importance of these findings are the low rate of CDI infection achieved by the VHA despite using a very sensitive assay.


Recently, Polage and colleagues[5] suggested that PCR was too sensitive a diagnostic method for CDI that could lead to falsely high rates of disease publically reported. They recommended adopting the model used in the United Kingdom, where molecular tests are not used as stand-alone tests for diagnosing CDI. The robust data from Young-Xu and colleagues indicate that an effective infection control program can achieve the goal of having low hospital-onset disease rates, even if a very sensitive test is used for diagnosis. The benchmark established by the VHA appears to be a laudable goal for most infection control programs.


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