Diagnostic stewardship approach to C. diff reduces unnecessary testing

July 1, 2024
New study from South Florida highlights the benefits of a clearly defined, evidence-based test ordering process.

A new study published in the American Journal of Infection Control (AJIC) describes the outcome of a new approach to testing for Clostridioides difficile (C. diff) guided by the principles of diagnostic stewardship.

At Memorial Healthcare System in Hollywood, FL, revised rules for when C. diff tests could be ordered helped to reduce inappropriate testing by 20%, which in turn can help rein in the overtreatment of patients.

In this study, clinicians from Memorial Healthcare System developed and implemented new guidelines to help reduce inappropriate testing for C. diff, and monitored results across the patient population for nine months to evaluate the approach. Those results were compared to testing performed in the year preceding the new ordering guidelines. The study reports results from 224 adult patients, 118 tested based on the new method and 106 from before the guidelines were implemented.

The new ordering approach involved two sets of rules: one for patients admitted within the last 72 hours, for whom C. diff testing could be ordered without restriction for any patient who recently had at least three loose or unformed stools, and the other for patients who had been in the hospital for four days or more. For the latter group, C. diff testing could not be ordered for patients who had been given laxatives within 48 hours, who had been treated for C. diff 14 to 24 days prior, or who had tested positive for C. diff within 14 days. Patients who had been tested for C. diff in the past four days, even if they received a negative result, were also not eligible for a new test. For high-risk patients, such as those who were immunocompromised or had recently undergone gastrointestinal surgery, C. diff tests could be given even if other eligibility guidelines were not met. The new system was integrated with the hospital’s electronic health records to ensure consistency and documentation, and educational resources were distributed to staff members.

Clinicians found a 20.1% reduction in C. diff test orders deemed inappropriate under the new system compared to the year prior to implementation, from 31.1% of tests before the new guidelines to just 11% with them. Testing was defined as inappropriate when patients did not have enough incidence of diarrhea reported or when there was recent laxative use without other signs of infection.

Additional details from the study include:

  • Following the adoption of new guidelines, clinicians saw an increase in 30-day readmission rates for patients in the study. An investigation noted a higher proportion of patients with recent gastrointestinal surgery in the post-intervention group compared to the pre-intervention group, and it was those patients who were more likely to be readmitted. Rates of readmission at 60 days remained higher for the post-intervention group, but the difference was no longer statistically significant.
  • Differences in 30-day and 60-day mortality across the two groups were not considered statistically significant.
  • Despite the ordering restrictions for patients who had taken laxatives in the previous 48 hours, there was no significant difference in exposure to laxatives in the groups of patients studied before and after the new ordering system was put in place.

APIC release