Changing Results to Change Results: Nudging Antimicrobial Prescribing for <em>Clostridium difficile</em>
Patients who test positive for Clostridium difficile by polymerase chain reaction (PCR), with a negative toxin enzyme immunoassay (EIA), are commonly colonized and do not require treatment. However, clinicians often treat based on a positive PCR result regardless of the toxin EIA result. We evaluated the clinical impact of a microbiology reporting nudge, changing from a report that included both assay results along with treatment recommendations to one that suggested clinicians consider C difficile colonization or early infection.
We conducted a retrospective cohort study of all adult patients admitted to a large multisite community hospital with a positive C difficile PCR result and negative toxin EIA from January 1, 2016 to June 30, 2018. We examined total days of therapy (DOT) and impacts on clinical outcomes.
One hundred ninety-nine episodes occurred preintervention and 165 episodes occurred postintervention. The mean DOTs per episode decreased from 13.6 to 7.9 days (difference −5.8 days; 95% confidence interval, −3.9 to −7.6) postintervention, with statistical process control charts suggesting special cause variation. Patients receiving no treatment increased from 6.5% to 23.6% postintervention (P < .0001). No significant changes in subsequent toxin positive disease (9.0% vs 6.7%), colectomy (0% vs 0.6%), mortality (7.5% vs 12.1%), or length of stay (18.5 vs 16 days) were observed.
Microbiology reporting nudges raising the possibility of C difficile colonization were associated with altered prescribing, reinforcing a postanalytic strategy for invoking change. Decreases in antimicrobial prescribing occurred without increasing subsequent disease or other adverse outcomes, suggesting a safe strategy for decreasing unnecessary treatment of C difficile colonization.
Clostridium difficile infection (CDI) is one of the most common causes of healthcare-associated infection. Although rates of other healthcare-associated infection have decreased, rates of CDI have increased more than 200% since 2000 [1, 2]. The increased incidence has corresponded to the increased uptake of molecular assays for C difficile detection. Data from the Centers for Disease Control and Prevention show that switching from toxin-based testing to polymerase chain reaction (PCR)-based testing increases CDI incidence by 43%–67% . The clinical relevance of C difficile detected by PCR in the absence of detectable toxin is controversial. Studies have shown no difference in patient outcome when a toxin-based enzyme immunoassay (EIA) is utilized with suppression of PCR results . This suggests that exclusive reliance on molecular tests such as PCR to diagnose CDI may result in misdiagnosis and subsequent complications from unnecessary treatment or incorrect diagnoses.
The presentation of microbiology reports has been shown to impact on prescriber behavior . We sought to measure the impact of providing additional interpretation of a positive PCR test result while preserving prescriber autonomy for prescribing when there was a concern of a high pretest probability of active disease and a false-negative toxin EIA result. In March of 2017, we implemented a new reporting protocol that suggests the likelihood of colonization for patients who tested positive for C difficile by PCR but had a negative toxin EIA. The purpose of this study was to determine the impact of the nudge from the microbiology laboratory on antimicrobial prescribing and clinical outcomes in this patient population.Click here for additional data file.(55K, docx)
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