Antibiotic utilization and de-escalation in cancer patients: a single-center observational study using DASC metrics

Days of Antibiotic Spectrum Coverage (DASC) is a novel metric that measures both the duration and spectrum of antibiotic use and has gained popularity for overcoming the limitations of traditional metrics, such as days of therapy (DOT) and patient-antibiotic days (PAD). Thus, this study aims to evaluate antibiotic consumption using DASC, along with traditional metrics such as DOT and PAD, among cancer patients.

A prospective observational study was conducted in oncology wards over a 1-year period (2024). DASC is the sum of antibiotic spectrum scores multiplied by the duration of treatment. Data was analyzed using descriptive statistics and Spearman's rank correlation coefficient.

The cumulative DOT, DOT/1000 patient-days, DASC, DASC/1000 patient-days, and PAD were 1195, 18840.2, 9749, 15,002.15 and 757, respectively. The antibiotic consumption was highest in the month of May (DASC: 2684, DOT: 349, PAD:172) and January (DASC:1314, DOT:151, PAD:116), but the DASC/DOT ratio was highest in March (9.18) reflecting the use of broader spectrum of antibiotics and the DASC/PAD ratio was highest in February (15.33), March (15.53), and May (15.6) reflecting the high intensity antibiotics/combination therapy with broad spectrum at each patient level. The DASC, DOT and PAD also showed a strong positive correlation (ρ>0.7, p < 0.001). Further, the DASC/PAD ratio showed a significant positive correlation with DASC/1000 patient-days (ρ = 0.580, p < 0.05), pointing towards measurement regimen intensity and spectrum, whereas the DASC/DOT ratio didn't show any correlation, indicating its potential to be an independent metric to measure average spectrum rather than volume of antibiotic used.

The DASC/DOT ratio assesses the average antibiotic spectrum, whereas the DASC/PAD ratio evaluates antibiotic intensity (concurrent antibiotics) and the total spectrum burden at the patient level. Thus, DASC, alongside DOT and PAD, may serve as complementary metrics for antimicrobial stewardship.