Evaluation of antimicrobial stewardship activities using antibiotic spectrum coverage

Recently, the days of antibiotic spectrum coverage (DASC) using the antibiotic spectrum coverage (ASC) score was reported as a new tool for measuring antimicrobial use. The days of therapy (DOT) are required to calculate the DASC, making it impossible to use when patient-level information is unavailable. Therefore, we have defined a new measure of antimicrobial use for antimicrobial spectrum coverage (AUSC) using antimicrobial use density (AUD) and ASC scores. In this study, we have investigated the use of antimicrobial agents retrospectively examined for monthly prescriptions between 2016 and 2022, and whether the AUSC could be used as a new measure. Our data showed that the AUD, AUSC, DOT, and DASC increased, whereas AUSC/AUD and DASC/DOT decreased over the study period. In addition, no correlation was found between DOT and DASC/DOT (ρ = - 0.093, p = 0.399), whereas there was a weak correlation between AUD and AUSC/AUD (ρ = - 0.295, p = 0.006). Therefore, in this study, the use of AUSC is considered less beneficial when DASC can be calculated based on DOT. On the other hand, in institutional settings where DOT cannot be calculated, AUSC may be useful as a new measure to evaluate antimicrobial use.