Efficacy of Carbapenems Compared With Noncarbapenem Broad-Spectrum Beta-Lactam Antibiotics as Initial Antibiotic Therapy Against Sepsis: A Nationwide Observational Study*

OBJECTIVES: As causative pathogens are not usually identified at the time of initiating antibiotics in sepsis, carbapenems are commonly used as an initial treatment. To reduce indiscriminate use of carbapenems, the efficacy of alternative empiric regimens, such as piperacillin–tazobactam and the fourth-generation cephalosporins, should be elucidated. This study aimed to evaluate survival effect associated with carbapenems as initial therapy for sepsis compared with these antibiotics. DESIGN: Multicenter retrospective observational study. SETTING: Tertiary hospitals in Japan. PATIENTS: Adult patients diagnosed as having sepsis from 2006 to 2019. INTERVENTIONS: Administration of carbapenems as initial antibiotic therapy. MEASUREMENTS AND MAIN RESULTS: This study used data of adult patients with sepsis extracted from a large-scale database in Japan. Patients were divided into two groups as follows: patients receiving carbapenems and patients receiving noncarbapenem broad-spectrum beta-lactam antibiotics as initial treatment. In-hospital mortality was compared between the groups by a logistic regression model adjusted by an inverse probability treatment weighting using propensity scores. To evaluate heterogeneity of effects according to patient characteristics, we also fitted logistic models in several subgroups. Among 7,392 patients with sepsis, 3,547 patients received carbapenems, and 3,845 patients received noncarbapenem agents. The logistic model showed no significant association between carbapenem therapy and lower mortality (adjusted OR 0.88, p = 0.108). Subgroup analyses suggested that there were significant survival benefits associated with carbapenem therapy in patients with septic shock, in ICUs, or with mechanical ventilation (p for effect modifications: < 0.001, 0.014, and 0.105, respectively). CONCLUSIONS: Compared with the noncarbapenem broad-spectrum antibiotics, carbapenems as an initial therapy for sepsis were not associated with significantly lower mortality.