In pursuit of the holy grail: Improving C. difficile testing appropriateness with iterative electronic health record clinical decision support and targeted test restriction

Objective: To determine the impact of electronic health record (EHR)-based interventions and test restriction on Clostridioides difficile tests (CDTs) and hospital-onset C. difficile infection (HO-CDI). Design: Quasi-experimental study in 3 hospitals. Setting: 957-bed academic (hospital A), 354-bed (hospital B), and 175-bed (hospital C) academic-affiliated community hospitals. Interventions: Three EHR-based interventions were sequentially implemented: (1) alert when ordering a CDT if laxatives administered within 24 hours (January 2018); (2) cancellation of CDT orders after 24 hours (October 2018); (3) contextual rule-driven order questions requiring justification when laxative administered or lack of EHR documentation of diarrhea (July 2019). In February 2019, hospital C implemented a gatekeeper intervention requiring approval for all CDTs after hospital day 3. The impact of the interventions on C. difficile testing and HO-CDI rates was estimated using an interrupted time-series analysis. Results: C. difficile testing was already declining in the preintervention period (annual change in incidence rate [IR], 0.79; 95% CI, 0.72-0.87) and did not decrease further with the EHR interventions. The laxative alert was temporally associated with a trend reduction in HO-CDI (annual change in IR from baseline, 0.85; 95% CI, 0.75-0.96) at hospitals A and B. The gatekeeper intervention at hospital C was associated with level (IRR, 0.50; 95% CI, 0.42-0.60) and trend reductions in C. difficile testing (annual change in IR, 0.91; 95% CI, 0.85-0.98) and level (IRR 0.42; 95% CI, 0.22-0.81) and trend reductions in HO-CDI (annual change in IR, 0.68; 95% CI, 0.50-0.92) relative to the baseline period. Conclusions: Test restriction was more effective than EHR-based clinical decision support to reduce C. difficile testing in our 3-hospital system.