Antibiotic spectrum coverage scoring as a potential metric for evaluating the antimicrobial stewardship team activity: a single-center study.

OBJECTIVE

Days of antibiotic spectrum coverage (days of ASC: DASC) is a metric for antibiotic usage calculated by ASC scores for spectrum and addresses limitations of days of therapy (DOT), which does not include spectrum. This study aims to investigate whether ASC-related metrics offer different aspects compared to aggregated DOT for all antibiotics (DOT) and to assess their correlation in evaluating the impact of antimicrobial stewardship team (AST) programs.

DESIGN

Retrospective.

SETTING

A single center within an 845-bed hospital.

METHODS

Trends in DOT, DASC, and the DASC/DOT ratio, representing the average spectrum coverage per therapy day, were analyzed pre- and post-AST programs (April 2018) from January 2015 to December 2023, using interrupted time series analysis. Independent of the DASC/DOT, we also advocated ASC-stratified DOT (ASDOT), which facilitates comprehensive evaluation of DOT across ASC scores of <6, 6-10, and >10, representing narrow-, intermediate-, and broad-spectrum antibiotics.

RESULTS

Among inpatients, AST programs significantly moderated the increasing trends of these metrics. Specifically, although the rates of increase in DOT and DASC were slowed or plateaued, the DASC/DOT ratio decreased ( < 0.001). ASDOT metrics revealed a decrease and subsequent plateau in DOT for the broad- and intermediate-spectrum antibiotics, with an increase observed for the narrow-spectrum antibiotics ( < 0.001 for each). DASC did not provide additional insights in the outpatient's population.

CONCLUSIONS

The study demonstrates that ASC-related metrics may yield different and useful conclusions about the effectiveness of AST programs for inpatients.