Healthcare resource utilization and readmission outcomes in patients treated with ceftolozane/tazobactam: real-world insights from the multinational SPECTRA study

Background Antimicrobial resistance poses a significant threat to global health, with Gram-negative pathogens contributing to morbidity, mortality and healthcare costs. While ceftolozane/tazobactam provides an effective treatment option against these pathogens, real-world data on healthcare resource use associated with ceftolozane/tazobactam, especially outside the USA, remain limited. Materials and methods This retrospective, multinational observational study includes 617 adult inpatients from Australia, Austria, Germany, Italy, Mexico, Spain and the UK who received ≥48 hours of ceftolozane/tazobactam. The outcomes included 30-day all-cause and infection-related readmission rates, hospital length of stay and post-ceftolozane/tazobactam length of stay. Subgroup analyses were conducted by rank of ceftolozane/tazobactam initiation, ICU admission and cystic fibrosis status. Results The overall 30-day all-cause readmission rate was 10.2%. The infection-related readmission rate was 4.9%. The median hospital length of stay was 42 days (IQR 22–71), and median post-ceftolozane/tazobactam length of stay was 6 days (IQR 1–25). Among ICU patients (n = 298), the 30-day all-cause readmission rate was 3.4% and median length of stay was 59 days. In cystic fibrosis patients (n = 64), the 30-day all-cause readmission rate was 10.9% and the median length of stay was 31.5 days (IQR 16–48.5). Conclusions This is the largest multinational, real-world dataset on healthcare resource use associated with ceftolozane/tazobactam outside the USA. These descriptive findings show differences in readmission rates and length of stay across rank-of-initiation groups; however, no causal relationships can be inferred from these data. The results are hypothesis-generating for future adjusted and economic analyses. Further research is warranted for economic evaluations and to optimize the timing of ceftolozane/tazobactam initiation.