The effect of renal dysfunction on antimicrobial use measurements

Area of Science:

• Pharmacokinetics and Pharmacodynamics
• Clinical Pharmacy
• Nephrology

Background:

• Defined daily dose (DDD) is a standard metric for antimicrobial consumption.
• Renal insufficiency can affect drug dosing and complicate antimicrobial use measurement.
• Accurate antimicrobial use metrics are crucial for stewardship and epidemiological studies.

Purpose of the Study:

• To evaluate the impact of renal dysfunction on antimicrobial use metrics.
• To compare the accuracy of defined daily doses versus therapy duration methods in patients with renal insufficiency.
• To identify the most reliable method for comparing antimicrobial use across populations with varying renal function.

Main Methods:

• Retrospective cohort study design.
• Inclusion of patients receiving ceftriaxone, levofloxacin, or vancomycin.
• Comparison of defined daily doses with two therapy duration methods: stop-start days and transaction days.

Main Results:

• Defined daily doses underestimated vancomycin use by 36% and levofloxacin use by 27% in patients with renal insufficiency.
• Transaction days showed a smaller underestimation for vancomycin (23%) compared to DDD.
• The stop-start day method demonstrated no significant reduction in antimicrobial use due to renal function.

Conclusions:

• Measures of therapy duration are less susceptible to bias from renal function compared to defined daily doses.
• Therapy duration methods, particularly stop-start days, may provide more robust comparisons of antimicrobial use between patient groups.
• Rethinking the use of defined daily doses in populations with impaired renal function is warranted.