Impact of pharmacist-driven antimicrobial stewardship interventions in a secondary care facility in Japan: A pragmatic quasi-experimental study.

Background: Efforts to promote antimicrobial stewardship aimed at reducing antimicrobial resistance are necessary regardless of hospital scale owing to delays in new antimicrobial development. We aimed to evaluate the effects of pharmacist-driven interventions on broad-spectrum antimicrobial usage and the prognosis of patients with bacteremia in a medium-sized hospital lacking infectious disease physicians and a microbiology laboratory.

Methods: This single-center, retrospective, pragmatic, quasi-experimental study was conducted to compare pre- and post-intervention effects at Saiseikai Futsukaichi Hospital. We analyzed the days of therapy (DOT) for carbapenems and days of antibiotic spectrum coverage (DASC) for antimicrobials using an interrupted time series analysis. Cox proportional hazards analysis was performed to assess 30-day mortality using propensity score and inverse probability of treatment weighting in patients with bacteremia.

Results: Pharmacist-driven interventions significantly reduced the DOT (incidence rate ratio [IRR]: 0.53, 95 % confidence intervals [CI]: 0.33-0.81, p = 0.003) and DASC (IRR: 0.87, 95 % CI: 0.78-0.97, p = 0.016). The 30-day mortality due to bacteremia did not significantly differ between pre- and post-intervention in all patients (adjusted hazard ratio [HR]: 0.92, 95 % CI: 0.56-1.51, p = 0.74). Conversely, pharmacist-driven interventions significantly reduced the 30-day mortality owing to bacteremia with Pitt bacteremia score (PBS) ≥4 (adjusted HR: 0.52, 95 % CI: 0.28-0.99, p = 0.047).

Conclusions: Pharmacist-driven interventions may represent a valuable approach for optimizing antimicrobial treatment and improving prognosis, especially in patients with PBS ≥4, which will potentially benefit patients in similar healthcare environments facing challenges related to antimicrobial stewardship and patient prognosis.