Antimicrobial prescribing in hospitals: be careful what you measure

Area of Science:

• Infectious Diseases
• Hospital Pharmacy
• Public Health

Background:

• Antimicrobial stewardship is vital for controlling infections and resistance.
• Standard metrics like defined daily doses (DDDs) per 1000 bed days are widely used but may be insufficient.
• Alternative methods for measuring antimicrobial prescribing have not been thoroughly evaluated.

Purpose of the Study:

• To evaluate multiple indices of antimicrobial use in a hospital setting.
• To compare different measurements of consumption and activity for systemic antibacterials.
• To determine if a single metric adequately captures antimicrobial prescribing patterns.

Main Methods:

• Analyzed electronically prescribed systemic antibacterial doses from 2008 across 14 hospital departments.
• Generated 10 indices of antimicrobial use by combining five consumption metrics (DDDs, agent days, courses, antibiotic days, treatment periods) with two activity metrics (bed days, finished consultant episodes).

Main Results:

• The 10 indices clustered into four distinct groups based on correlation.
• These groups represented volume-related consumption (DDDs, agent days, antibiotic days) and exposure-related consumption (courses, treatment periods).
• Each consumption type was denominated by either bed occupancy (bed days) or patient throughput (finished consultant episodes).

Conclusions:

• Different antimicrobial use indices provide unique and complementary information.
• Relying solely on DDDs per 1000 bed days may underestimate or misrepresent antimicrobial prescribing.
• Further research is needed to identify which indices best predict antimicrobial-related risks like resistance or C. difficile infection.