Practice Model of Unit-based Clinical Pharmacists' Individualized Daily AUD Monitoring Report on Antimicrobial Stewardship in ICU of a tertiary hospital in Guangxi, China: An Interrupted Time Series Analysis

Background High antimicrobial resistance and consumption intensity in the Intensive Care Unit (ICU) present critical challenges to patient safety. While the Unit-Based Clinical Pharmacist (UBCP) model is a recommended strategy, the specific impact of combining UBCP with individualized data monitoring tools remains to be fully evaluated. This study aimed to assess the effectiveness of a UBCP model, facilitated by a manual Individualized Daily Antimicrobial Use Density (AUD) Monitoring Report (IAUD-RP), on antimicrobial stewardship in the ICU. Methods A single-center, retrospective, quasi-experimental study using interrupted time series (ITS) analysis was conducted in a 12-bed ICU of a tertiary teaching hospital in Guangxi, China. A total of 657 adult patients admitted between April 1, 2023, and October 31, 2025, were included. The intervention, initiated in August 2024, involved the implementation of a UBCP practice model utilizing manual IAUD-RP for real-time risk stratification and precision intervention. The primary outcome was AUD, measured as defined daily doses (DDDs) per 100 patient-days. Secondary outcomes included average antimicrobial cost per hospitalization (AACPH) and antimicrobial consumption structure. Results Among the 657 included patients (295 pre-intervention; 362 post-intervention), pharmacist interventions achieved a 91.7% acceptance rate. ITS analysis demonstrated a significant immediate reduction in AUD (level change, -29.0 DDDs; P = 0.038) following the intervention, successfully reversing a significant pre-intervention upward trend (slope, + 2.6; P = 0.005). Although the ITS model showed no significant immediate level change for costs, the overall mean AACPH decreased significantly from 25,568 CNY to 14,926 CNY (P < 0.001). The antimicrobial consumption structure improved substantially, characterized by significant reductions in tigecycline (-52.1%), quinolones (-39.7%), and carbapenems (-15.8%), alongside a 99.2% increase in WHO Access group antibiotics. Conclusions The UBCP model, empowered by the visualized real-time feedback of IAUD-RP, effectively curbed the growth of antimicrobial intensity, reduced treatment costs, and optimized prescribing structure by promoting the shift from broad-spectrum empirical use to targeted therapy.