Discussion

Utilization of an electronic hard stop was effective in reducing unnecessary C. difficile testing, resulting in lower HCFO-CDI rates with no reported adverse events associated with delayed testing. Decision making for CDI testing is challenging and requires astute clinical judgement given the lack of specificity for causes of diarrhea in inpatients. ^{Reference Kara, Tahir, Snyderman, Brinkman, Fadel and Dbeibo7} In this population, CDI accounts for just 10%–20% of cases of diarrhea, whereas medications, including promotility agents, antimicrobials, and tube feeding account for the overwhelming majority. ^{Reference Solanky, Juang, Johns, Drobish, Mehta and Kumaraswamy8} Due to highly sensitive NAAT that cannot distinguish colonization from infection, restricting testing to patients with no alternative causes for diarrhea is essential in preventing inappropriate diagnosis of CDI and overtreatment.

Diagnostic stewardship is an effective strategy for reducing inappropriate C. difficile testing in inpatient settings. ^{Reference Solanky, Juang, Johns, Drobish, Mehta and Kumaraswamy8–Reference Mizusawa, Small and Hsu10} Soft stops, such as clinical decision support algorithms and best practice alerts (BPAs), are commonly used to mitigate unnecessary testing, especially in the setting of promotility agents. However, hard stops that actively block orders are underutilized despite being more effective. ^{Reference Sullivan, Gallagher and Leekha9,Reference Mizusawa, Small and Hsu10} Solanky et al ^{Reference Solanky, Juang, Johns, Drobish, Mehta and Kumaraswamy8} implemented measures, including a test-ordering algorithm outlining patient criteria for C. difficile testing incorporated into the EMR, which reduced inappropriate testing. However, clinicians were able to order testing even if criteria were not met. ^{Reference Solanky, Juang, Johns, Drobish, Mehta and Kumaraswamy8} In another study, a BPA was triggered in various settings, including laxative administration in the preceding 48 hours. Overriding the BPA activated a hard stop in which testing could not proceed without microbiology laboratory approval. The laboratory approved all orders upon request and provided a passcode for new order entry. ^{Reference Mizusawa, Small and Hsu10}

Unlike other studies, our testing hard stop was triggered by objective measures captured in the EMR. Our intervention was also novel because it included a consultation with the medical director of infection prevention upon provider request if testing was denied. This expert review of individual cases provided for prompt feedback, education and shared decision making. Providers were encouraged to address confounding factors, including discontinuation of promotility agents, and explore alternative causes.

After the intervention, we also evaluated CO-CDI rates to ensure that there was no increase due to possible delayed testing. CO-CDI rates decreased, and no patients were readmitted with CDI due to delayed testing. In addition to being safe and effective, the intervention had the additional benefit of quality improvement and cost savings for the health system, with an estimated net savings of nearly $7 million. ^{Reference Zhang, Palazuelos-Munoz, Balsells, Nair, Chit and Kyaw4}

Given the retrospective quasi-experimental nature of this study, these results are subject to inherent limitations. Additionally, the number of hard stops that were fired is unknown, making it difficult to gauge the true number of reduced C. difficile test orders. For test orders for which an override was approved, the reasons for override were not collected. Prior studies have noted that the most frequent reason for an inappropriate CD test was reporting of diarrhea by a patient or a nurse. ^{Reference Kara, Tahir, Snyderman, Brinkman, Fadel and Dbeibo7} This information could inform future quality-improvement initiatives.

We observed reductions in C. difficile testing, HCFO-CDI rates, and SIR after implementation of an electronic hard stop with optional expert review. Incorporating this strategy into best practices, such as provider education, handwashing, and contact isolation, can significantly reduce HCFO-CDI rates.