# 191. Long-term Utility of Clinical Nudges within Clostridioides difficile Diagnostic Stewardship

## TL;DR

This study shows that using computer alerts to remind doctors about proper testing for a specific infection significantly reduced unnecessary tests and improved diagnostic accuracy over time.

## Contribution

The study demonstrates the long-term effectiveness of clinical decision support nudges in reducing inappropriate Clostridioides difficile testing and improving diagnostic stewardship.

## Key findings

- An informational alert decreased CDI testing and lowered test positivity rates in patients at low risk for infection.
- Overrides of alerts were most common in ICU settings and among certain provider types.
- A small group of providers was responsible for a large proportion of alert triggers and overrides.

## Abstract

IDSA recommends that, prior to testing for Clostridiodes difficile in patients with new-onset diarrhea, clinicians should consider other potential causes, such as recent laxative use. Clinical decision support systems (CDSS) can nudge providers to reduce inappropriate CDI testing and 2-step testing algorithms can optimize diagnostic accuracy. We assessed the long-term clinical utility of clinical nudges for CDI diagnostic stewardship.

A retrospective analysis of inpatient CDI tests (n=44,677) ordered for 10 years after the introduction of 2-step diagnostic testing (toxin→DNA-NAAT) in the 2nd quarter of 2015 (Q2 2015) to evaluate the long-term impact of a CDSS nudge for providers to reconsider testing in patients receiving laxatives in the 48 hours prior. Univariate and multivariate analyses were performed via Pearson’s chi-squared test.

An informational popup (Q3 2016) produced a marked decrease in CDI testing (Fig. 1). It was transitioned to an interactive popup prompting either cancelation or acknowledgment that a “positive result will be of no value” (Q2 2017). The test positivity rate was significantly lower (7.0% vs. 8.5%, P < .001) for inpatients who triggered the popup (n=9231) versus those who did not during the same period.

No significant change in overall propensity to override the CDSS popup was observed over the study period (µ=57%). Popups were most frequently overridden in ICUs (62.0%), compared with Floor and Post-Acute Units, at 56.1 and 58.0%, respectively (p< .0001). There was a significant difference in rate of override between ordering provider types (APP vs. Attending vs. Resident) with rates of 59.4%, 57.2% and 55.5%, respectively (p< .01). In looking at individual providers, 2.5% of providers (n=50) were responsible for 20% of popup triggers, with a negative correlation between frequency of override and ordered test positivity (Fig. 2).

While it has been shown that CDSS nudges can decrease diagnostic ordering, here we show that implementation of a CDSS yielded a statistically significant decrease in test positivity for a patient population at low-risk for CDI. Subgroup analyses looking at provider, unit, and level of care provide opportunities for targeted educational intervention to further improve diagnostic stewardship.

All Authors: No reported disclosures