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Friday, December 23, 2016 Written by Jorge P. Parada, MD, MPH, FACP, FIDSA, Prof. of Medicine, Stritch School of Medicine Loyola University, Chicago

Improving Patient Safety

Loyola Meets the C. difficile Challenge

As noted in the June 2012 issue of Impact, there is a great deal of pressure on hospitals to be more accountable, and the pressure is only growing. Accountability reporting will impact hospital finances on multiple fronts: from reimbursement changes to patient hospital selection for elective procedures.

Needless to say, Healthcare associated infections (HAIs) are a key part of the accountability metrics required and soon-to-be required. In our first article, we explored Loyola University Hospital’s implementation of rapid, highly sensitive universal screening to successfully combat methicillin-resistant Staphylococcus aureus (MRSA).(1) In this article, we’ll look at how the hospital addressed another common and increasingly troublesome HAI: Clostridium difficile (C. difficile).

The rates of C. difficile infection are increasing globally and also becoming more lethal. It is a universal problem, found rural and urban areas, teaching hospitals and non-teaching hospitals. The costs associated with C. difficile are $1–3 billion annually, and on average, a C. difficile infection increases the patient’s length of stay (LOS) by approximately three days. This is a shorter average increase in LOS than seen with MRSA infections, but there are two to four times more cases of C. difficile.

There are two key contributors to the increasing C. difficile mortality rates: a hyper-virulent strain (BI/NAP1/027) has appeared in the United States, Canada, and Europe. The 027 strain produces 20 times more toxins than most previously circulating strains(2). As discussed in “The C. difficile Challenge” (Impact, June 2012), there has been a correlating increase in both costs and length of stay (LOS) associated with the emergence and spread of the 027 strain.


Source: AHRQ, Center for Delivery, Organization, and Markets, Healthcare Cost and Utilization Project, Nationwide Inpatient Sample, 1993–2009.

The second key factor in the increasing C. difficile mortality rates (particularly in the US) is the aging population. While C. difficile infections are being seen even in “low-risk” populations, older age groups do catch it more easily and have more severe resulting illness. With continuing increases in our elderly population projected (Figure 3), we have an increasing number of vulnerable patients and not surprisingly, more C. difficile infections.

*Projections for 2010 through 2050 are from: Table 12. Projections of the Population by Age and Sex for the United States: 2010 to 2050 (NP2008-T12), Population Division, U.S. Census Bureau; Release Date: August 14, 2008

The source of the data for 1900 to 2000 is Table 5. Population by Age and Sex for the United States: 1900 to 2000, Part A. Number, Hobbs, Frank and Nicole Stoops, U.S. Census Bureau, Census 2000 Special Reports, Series CENSR-4, Demographic Trends in the 20th Century, 2002

This table was compiled by the U.S. Administration on Aging using the Census data noted.

 

The Importance of Identifying C. difficile

The undisputed gold standard for C. difficile testing is stool culture. It is not, however, widely used as it is labor-intensive, difficult, and slow, with results taking several days. As a result, stool culture’s use is limited to a handful of specialty laboratories. The most common test used for C. difficile is enzyme immune assays (EIA), which are fast and inexpensive. As of 2006, 95% of hospitals were using EIA to test forC. difficile, and the vast majority are still using this (or EIA testing) as a standalone test. The issue with EIA is accuracy — the assays have been found to be as little as 33% sensitive(3). In fact, IDSA/SHEA C. difficile Guidelines in May 2010 note that EIA is no longer recommended as a standalone test for C. difficile.

PCR-based molecular diagnostics have emerged as a strong contender for rapid, accurate results. The PCR-based tests are 97% accurate. Recent advances in testing include Cepheid’s Xpert® C. difficile/Epi test, which additionally provides identification of NAP1/027 strains. Rapid identification of C. difficile enables the correct patients to be placed in isolation and given appropriate treatment. (Figure 4)

a. Xpert C. difficile Clinical Trial Data;
b. Gilligan, et al. JCM 2008;
c. Sloan, et al. JCM 2008;
d. Alcala, et al. JCM 2008; d. Barbut, et al. JCM 2009
* Test performance assessments based on independent peer reviewed publication. Performance assessments do not represent “head” to “head” comparisons.

Loyola Implements Molecular Diagnostics

Loyola University Medical Center had clearly identified the costs of EIA unreliability.

The lack of confidence in EIA test results was causing physicians to place negative patients on isolation and treat them anyway. The buy-in for use of personal protective equipment was undermined, and the environmental contamination and C. difficile transmission continued to be problematic.

The solution? The hospital decided to use molecular diagnostics to combat their C. difficile challenge. Their success was facilitated by the GeneXpert® System, which improved two key things: turnaround time and test accuracy. Loyola’s mean turnaround time (TAT) for C. difficile testing dropped by 90%, with results provided in 93 minutes, compared with 909 minutes previously. Accurate results identified 75% more positives, thus preventing transmission by unidentified infected patients. A beneficial halo effect was seen as the hospital staff responded to the dramatically improved TAT. Knowing how quickly results would be returned, they recognized an opportunity to act, and delivered samples to the lab more quickly, decreasing the time to result even further.

Implementation of on-demand molecular diagnostics for C. difficile at Loyola has meant:
• 2/3 fewer people on isolation — 4000 fewer isolation days
• Reduced need for personal protective equipment (gloves, gowns, etc.)
• Reduced length of stay, fewer blocked beds
• Higher quality of care — patient confidence, better health

What Loyola observed with both MRSA and C. difficile, is that rapid-result PCR saves money while improving quality of care – you must keep the big picture in mind: spending in the “lab silo” enables great savings and/or revenue opportunities in other silos.

References:

1. Parada, J. Increase Revenue and Improve Patient Safety. Impact, June 2012. P 8–11.
2. Vohra, P & I Poxton. Comparison of toxin and spore production in clinically relevant strains of Clostridium difficile. Microbiology.
3. Tenover et al. Journal of Clinical Microbiology, October 2010, p. 3719–3724, Vol. 48, No. 10