Packaged intervention targeting oral antimicrobials in Japanese tertiary care outpatient setting: a quasi-experimental study.

OBJECTIVES

To evaluate an outpatient, antimicrobial stewardship intervention targeting broad-spectrum antimicrobials including third-generation cephalosporins, fluoroquinolones, and macrolides, during an antimicrobial shortage at a Japanese, tertiary hospital.

METHODS

This before-and-after interventional study was conducted at a tertiary hospital. The intervention included department-focused and hospital-wide education, local guidelines, weekly post-prescription review and feedback, monthly reports on days of therapy (DOT), a formulary review, and an orientation for newly transferred physicians. Counterfactual monthly outcomes (primary endpoint: DOT per 100 visits (DOT/100V) and number of prescriptions per 1000 visits (Rx/1000V) for the target antimicrobials) were predicted on the basis of pre-intervention data using ordinary least squares regression incorporating oral antimicrobial shortages.

RESULTS

The post-intervention use of third-generation cephalosporins decreased (DOT/100 V mean difference [MD]: -0.87; 95% confidence interval [CI]: -0.97 to -0.76; Rx/1000 V MD: -3.85; 95% CI: -4.06 to -3.65) together with that of fluoroquinolones (DOT/100V: -1.92; 95% CI: -2.33 to -1.51; Rx/1000V MD: -2.14; 95% CI: -2.60 to -1.68). The volume and frequency of macrolide use did not differ significantly, but inappropriate prescriptions of fluoroquinolones (-26.22%) and macrolides (-7.92%) decreased.

CONCLUSIONS

This outpatient stewardship programme evaluated within a counterfactual framework accounted for supply shortages, reduced third-generation cephalosporins and fluoroquinolone use, and improved the appropriateness of prescriptions. Sustaining these gains requires on-going evidence-based data-sharing and prescriber-tailored interventions.