Table 2.

Clinical Decision Support Diagnostic Stewardship Interventions

Category	CDS Intervention	Example	Intervention	Reported Results/Outcomes
Education	Electronic references	Sopena et al [71]	Online course for healthcare personnel on epidemiology and clinical manifestations of CDI, diagnosis of CDI, transmission, prevention, treatment.	Statistically significant increase in overall incidence of HO-CDI and community acquired CDI. Statistically significant increase in use of optimal diagnostic algorithm.
	Preanalytical/Laboratory based	Truong et al [57] Yen et al [39] Lin et al [75]	Laboratory personnel rejected formed stool, repeat orders within 7 days, laxative use within 48 hours, and less than 3 unformed stools in 24 hours. NAAT orders cancelled by laboratory if stool sample not received within 24 hours of order placement, or if the stool was formed. All CDI testing on hospital day four or later required mandatory approval by an ID specialist.	Statistically significant decrease in HO-CDI rates and vancomycin utilization. No increase in CDI-related complications for patients with cancelled tests. HO-CDI-SIR significantly lower statistically. Average number of total tests decreased. HO-CDI testing and rates significantly declined statistically after the intervention. There was a mean of 1.3 pager approvals per day, with a range of 0–4. Each call took on average three minutes.
Test Ordering	Order set modification/reflex orders and cascade ordering	Revolinski et al [66] White et al [59] Madden et al [63]	Order set for guidelines for treatment of CDI based on mild, moderate, severe, severe-complicated, and recurrent disease. Providers required to use order set to order C. difficile testing. Providers were alerted to laxative use in the prior 36 hours. 2-part CCDS tool showing duplicate orders and questions to ensure appropriate testing.	Only noted one use of the order set within 6 months so BPA added when ordering oral vancomycin or NAAT testing. After BPA order added, use increased but guideline compliance unchanged. Statistically significant decrease in inappropriate testing. Increase in discontinuation of laxatives in patients with diarrhea. Proportion of patients tested for C. difficile did not change. 41% reduction in overall testing. 31% fewer HO-CDI events. Percentage of positive CDI result did not significantly change.
	“Hard” or “soft” stop alerts	Bilinskaya et al [67] Friedland et al [64] Kwon et al [11] Quan et al [60] Mizusawa et al [84] Otto et al [70]	Soft stop BPA for C. difficile PCR order if laxative use within 24 hours. Soft stop alerts based on stool documentation, laxative use, prior C. difficile testing placed in EMR and gave provider decision to cancel testing. Hard-stop intervention to limit repeat EIA testing within 96 hours of prior negative and within 10 days of prior positive. Automated real-time computer order alert for appropriate testing. Any contraindication resulted in a hard stop requiring ID or GI consult. 2 step BPA in the setting of laxative use within 48 hours, negative C. difficile testing within 7 days, or positive test within 14 days. If first BPA bypassed by clinician, then lab approval required as second BPA. Four hospital information system alerts that C. difficile testing was not recommended within 7 days of positive, C. difficile testing not recommended within 48 hours of prior negative, stool testing for O&P not recommended after hospitalized for 72hrs. Hard stop for ID consult required to override orders.	75.4% of alerts immediately overridden. 13.8% initially cancelled then reordered. Patients who had C. difficile testing were significantly more likely to have diarrhea, less likely to have laxative use, more likely to have documented reason for testing. Clinically indicated testing significantly improved statistically. No change in CDI rates. Statistically significant decreases in CDI testing rates and mean number of tests per admission. Overall rate of positive tests did not change. No increases in 30-day mortality. No change in C. difficile targeted antibiotics. CDI testing decreased 56%. Testing on laxatives decreased 64%. HO-CDI decreased 54%. Reordered CDI tests decreased by 64%. After CCDS, all hospitals saw significantly reduced testing orders. 15.4% followed the initial BPA and 57.7% followed the second BPA. Fellows and attendings more likely to follow BPA. Overall volume of C. difficile orders increased, but noncompliant orders decreased, and repeat orders decreased.
Diagnostics	Decision support algorithms	Fleming et al [12] Sperling et al [65 Madden et al [85]	Decision support embedded in EMR. Appropriate testing defined as 3 or more stool in 24 hours, watery diarrhea on days 1–3, no laxative use within 24 hours, and confirmation of fever, abdominal pain, white blood cell count >15/mm3. Clinicians had to complete yes/no questions on stool frequency, laxative use in past 24 hours, tube feedings, and abdominal pain, fever, elevated white blood cell count. Clinicians could continue with order regardless of responses. Lab and IP also performed review to make sure stool unformed and patient not on laxatives. 2-part CCDS with duplicate alert and algorithm questioning regarding presence of diarrhea, symptoms of CDI, or risk factors for infection to encourage appropriate testing.	Significant (27%) decrease in total C. difficile testing. Significant improvement in appropriateness of CDI testing. Significant reduction in HO-CDI-IR. C. difficile testing reduced by 42%. HO- CDI LabID rates decreased by 59%. HO-CDI-SIR decreased below CMS threshold. No adverse events noted. 33% reduction in rates of C. difficile testing. Nonsignificant reduction in LabID CDI events. During the intervention, 22.5% were prevented by CCDS and 7.1% rejected by the lab.
	Feedback and benchmarking	Buckel et al [44] Christensen et al [26] Fabre et al [73] Jakharia et al [86] Schultz et al [74]	Education to nursing and pharmacy on CDI testing indications prior to intervention involving pharmacy recommendations on testing and CDI treatment. Pre-intervention education on appropriate testing. Intervention included antimicrobial stewardship program prospective clinical review with recommendation to cancel or proceed with testing. Intervention followed by two-step CCDS tool for documentation of diarrhea and prior testing within 7 days. Face-to-face feedback for nurses (stool documentation) and providers (colonization, CDI treatment optimization, stopping unnecessary antibiotics, stopping laxatives and PPIs). Weekday review of C. difficile orders placed. Samples that did not meet inclusion criteria were discussed with ordering provider. Providers were allowed to override recommendations. Eight categories of interventions: diagnostic stewardship, electronic tools, education, isolation precautions, hand hygiene, environmental cleaning, antimicrobial stewardship, and pharmacy intervention.	Laxative use within 48 hours prior to testing and in those with a positive test result showed statistically significant decrease. Overall documentation of stool frequency was not different. Significantly decreased CDI testing and overall CDI rate. Recommendations for not treating asymptomatic colonization deemed unsuccessful. Mean monthly number of positive NAAT results significantly decreased. HO-CDI-IR and SIR significantly decreased. Decrease in oral vancomycin use. Significant improvement in stool documentation. Suboptimal antibiotic and PPI use significantly decreased. Treatment of C. difficile colonization did not significantly change. Laxative use similar. Whole genome sequencing detected a diverse population that lacked clonality. The rate of testing and HO-CDI decreased during intervention. No change in rate of CA-CDI. Significantly reduced HO-CDI, CD testing. HCP compliance with gowning and gloving decreased.