Impact of a pharmacist driven antimicrobial stewardship program on inpatient antibiotic consumption in a Chinese Tertiary Hospital: a 5-year retrospective study

Abstract

Introduction: Antimicrobial Stewardship programs are crucial for reducing overall antibiotic consumption, but in practice, there are often issues with unclear responsibilities and ambiguous tasks. Pharmacists play a critical role in AMS due to their combined management functions and professional expertise.

Objective: To investigate the impact of a Pharmacist-Driven Antimicrobial Stewardship program on the consumption of antibiotics in a hospital.

Methods: Under the support of a hospital top-level design, we implemented a Pharmacist-Driven Antimicrobial Stewardship program led by pharmacists and involving multiple disciplines. The program focused on revising the antibiotic formulary and optimizing key points of antibiotic management, using the inpatient Antibiotic Use Density as the core control indicator. This was conducted through three phases: program initiation, implementation, monitoring and control. Clinical pharmacists ensured the long-term operational quality of the program. We evaluated the impact of the program on relevant indicators of antimicrobial consumption in inpatient.

Results: Compared to the pre-implementation year of 2020, the annual Antibiotic Use Density for inpatients across the hospital decreased by 22.28% in 2024, reaching 36.26 defined daily doses/100 patient days. Additionally, the monthly inpatient Antibiotic Use Density in 2024 was significantly reduced (p < 0.001), along with the antibiotic usage rate (p < 0.05), expenditure on antibiotics per inpatient (p < 0.001), and the proportion of antibiotic expenditure relative to total for inpatients (p < 0.001). The rational use of antimicrobial agents in inpatient wards has been enhanced. Through targeted management, some antibiotics showed trends of increased or decreased usage. The detection rates of Methicillin-Resistant Staphylococcus aureus and Extended-spectrum β-lactamase-producing Escherichia coli did not show a significant decrease.

Conclusion: The Pharmacist-Driven Antimicrobial Stewardship program effectively leveraged the managerial roles and professional skills of pharmacists in rational drug use management, resulting in a significant reduction in hospital antibiotic consumption. However, to further validate its effectiveness in reversing bacterial resistance, the program requires longer-term operation and could be considered for regional expansion.

Keywords: antibiotic consumption; antibiotic use density; antimicrobial stewardship; hospital pharmacy; rational drug use.

FIGURE 1

Pharmacist driven antimicrobial stewardship program implementation flowchart.

FIGURE 2

The timeline of the pharmacist driven antimicrobial stewardship program activities.

FIGURE 3

Driver’s-License-Style” System flowchart.

FIGURE 4

Changes in inpatient antibiotic use density (2020–2024). The line graph is based on monthly data. The red dashed line represents the national control limit for tertiary general hospitals (<40 DDDs/100 patient days). Phase 1: Initiation; Phase 2: Implementation; Phase 3: Monitoring and Control.

FIGURE 5

Changes in inpatient antibiotic usage rate (2020–2024). The line graph is based on monthly data. The red dashed line indicates the national control limit for tertiary general hospitals (<60%). Inpatient Antibiotic Usage Rate (%) = 100% × Number of hospitalized patients using antibiotics/Total number of hospitalized patients in the same period.

FIGURE 6

Changes in expenditure and proportion of antibiotics for inpatients. The line graph is based on monthly data. Proportion of antibiotic expenditure in inpatients (%) = 100% × total cost of antibiotics used by inpatients/Total cost of all medications used during the same period. The red dashed line represents the monthly expenditure on antibiotics per inpatient in 2024, after adjusting for the impact of the VBP policy.

FIGURE 7

Changes in inpatient antibiotic use density for major antibiotics. The heatmap is based on monthly data, different classes of antibiotics are represented by different color clusters in the heatmap, each with its own scale. Within the same class of antibiotics, the darker the color, the higher the inpatient antibiotic use density (AUD) for that month, indicating greater consumption. “Inj.” denotes injectable formulations, while “Oral” denotes oral formulations.

FIGURE 8

Changes in points deducted by the “Driver’s License-Style” System. The line graph is based on quarterly data, with each data point reflecting the total points deducted for irrational antibiotic use in inpatient wards during that quarter’s review.

FIGURE 9

Change in severe allergy cases among cephalosporin ADRs. Note: Period 1: 2018–2020. Period 2: 2021-2024.

FIGURE 10

Resistance rates of Staphylococcus aureus to oxacillin and Escherichia coli to ceftriaxone. The line graph is based on semiannual data. The blue dashed line represents the linear trendline based on the least squares fit.