Is a "Hard Stop" Method the Key to Reducing Inappropriate C. difficile Testing?

A testing stewardship effort found that using a “hard stop” alert system may help reduce inappropriate C. difficile testing.

Classified by the Centers for Disease Control and Prevention (CDC) as an urgent threat to public health, Clostridium difficile (C. difficile) infections (CDIs) continue to pose a huge challenge in health care facilities everywhere.

As such, practitioners have been openly sharing with each other different methods that they have tried in their own facilities to get a leg-up on a disease that results in about 14,000 deaths per year and $1 billion in excess medical costs.

At ID Week 2017 in San Diego, California, Marci Drees, MD, MS, FACP, DTMH, infection prevention officer and hospital epidemiologist for Christiana Care Health System, delivered a short presentation as part of an Oral Abstract Session discussing a testing stewardship approach involving a “hard stop” to reduce inappropriate CDI testing.

“Testing, or diagnostic stewardship, involves modifying the process of ordering, performing, and reporting diagnostic tests to improve treatment of infections,” Dr. Drees said. She then explained how modifying the process of ordering tests, specifically, is a way to reduce inappropriate testing in health care facilities.

Dr. Dree’s community-based academic tertiary care system located in northern Delaware consists of 2 facilities: a large suburban hospital consisting of 913 beds, and a small urban acute care hospital consisting of only 241 beds. The care system recently transitioned from a 2-step algorithm for CDI testing that included an enzyme immunoassay (EIA) and polymerase chain reaction (PCR) testing to PCR testing only in January 2015. Immediately after this transition, the hospital reported a 20%-25% increase in positive CDI tests.

“Of course, we did, at the time, educate our clinicians about this new testing algorithm—that it was going to be sensitive and that we should be smart about how we’re testing,” Dr. Drees added. “But, as we were starting to see these cases rolling in, the infection preventionist that reviews all the cases noted that many of them that were turning positive were tested in a setting of recent laxative use.”

She noted that to ensure diagnostic accuracy, patients who are tested should:

  1. Have documented diarrheal disease
  2. Have not received laxatives in the past 48 hours

To ensure testing appropriateness, Dr. Drees’ institution introduced multiple initiatives. One such initiative was a laxative alert, kicked off in March 2015, which Dr. Drees described as a “soft stop” approach. “The alert was designed to inform the ordering provider of laxatives that had been administered in the prior 24 hours,” she explained. “It initially reduced orders [for tests] by 25%.” However, the approach lost effect over time.

Another initiative included the development of a multidisciplinary “Tiger Team” that would meet intensively—at least 1 or 2 times a week—to discuss and devise new ways to improve appropriate testing. The team’s initial analysis of CDI testing in the care system showed that about 50% of the cases identified as hospital-onset CDI were likely only cases of C. difficile colonization. In addition, those cases had “either received laxatives prior to testing positive or did not have documentation of significant diarrhea, as determined by case review,” said Dr. Drees.

To address this issue, the Tiger Team launched a prospective performance improvement project using a new “hard stop” laxative alert. The alert, which would fire 36 hours after admission, “first assess[ed] for documentation of diarrhea—more than 2 episodes per 24 hours—and if that was present, we would then look for laxative use within the prior 24 hours,” Dr. Drees explained. “If neither of those criteria were met, the ordering provider could still proceed with the order but only by calling the lab and documenting the name of the person who was ordering from the lab.” No further justification for the test order was required.

A further breakdown of how the algorithm works is listed below:

  1. Assessment for the presence of diarrhea. If it’s not present, then the order for testing is discontinued, unless the provider calls for an override. If it is present, then the ordering provider will receive an alert.
  2. Alert prompts the provider to look for recent laxative use. If there is none, the order proceeds. If there is documented laxative use, then the provider is issued another alert which will prompt them to cancel the order to override.

How well did the hard stop alert work? After the alert went active, the team saw an “immediate drop in testing” from a mean of 12 C. difficile testing orders per day when using the soft stop alert to 7. “Similarly, our hospital-onset CDI cases also declined [from a mean of 3.6 cases/week down to 2 cases/week],” Dr. Drees added. “Aside from a slight uptick in August, if we look at the time period of our intervention and compare it with the exact same time period a year before, or if we compare it to a longer time period starting in January 2016, we see statistically significant decreases in our rate ratio.”

In addition, Dr. Drees and her team have yet to identify any delayed diagnoses or empiric treatment with oral vancomycin without testing. However, a total of 18 override calls were reported.

Dr. Drees noted that the study was not without limitations. First, the project didn’t address or prevent true C. difficile disease (“which is really what we want to do,” she said). Second, it was a single health care-system, pre-post study, and as a symptom, diarrhea is not always well-documented. Finally, Dr. Drees noted that even a hard stop approach can lose effectiveness over time as providers figure out ways around it.

“Testing stewardship is really critical to minimize false-positive CDI cases which could lead to inappropriate treatment, prolonging the stay and patient dissatisfaction. And, it does put you at risk for hospital penalties. Limiting testing using the hard stop method was certainly more effective than a suggestion to cancel the test and it was generally well-accepted,” Dr. Drees concluded.

What are the next steps for the health care system?

“Our next steps are to automate some of the processes in terms of detecting delays in testing,” said Dr. Drees. “We are also evaluating the C. difficile scoring tool to identify other low-risk patients. We have some ongoing/increasing efforts to reduce our “true positive” CDIs, including the statewide ‘Choosing Wisely,’ antibiotic stewardship campaign, ongoing environmental cleaning assessments, and we’re ramping up the patient hand hygiene and bathing efforts.”