Indirect Standardization as a Case Mix Adjustment Method to Improve Comparison of Children's Hospitals' Antimicrobial...

Area of Science:

• Pediatric Healthcare Research
• Antimicrobial Stewardship
• Health Services Research

Background:

• Antimicrobial use (AU) varies widely among children's hospitals, measured in days of therapy per 1000 patient-days (DOT/1000 pd).
• Current measurements inadequately address case mix, a key factor influencing this variation.
• Effective antimicrobial stewardship requires accurate comparisons between institutions.

Purpose of the Study:

• To evaluate indirect standardization as a method to adjust AU for patient case mix.
• To compare the variability of adjusted AU (O:E ratios) with unadjusted DOT/1000 pd.
• To assess the utility of indirect standardization for enhancing antimicrobial stewardship efforts.

Main Methods:

• Utilized hospitalization data from the Pediatric Health Information System.
• Grouped hospitalizations into 85 distinct clinical strata.
• Calculated observed to expected (O:E) ratios using indirect standardization and compared them with DOT/1000 pd.

Main Results:

• Unadjusted antibacterial DOT/1000 pd showed a 2.2-fold variation (345-776), while O:E ratios demonstrated a smaller 1.4-fold variation (0.8-1.14).
• O:E ratios were moderately correlated with DOT/1000 pd (correlation estimate 0.44, P=.0009).
• Indirect standardization effectively reduced the apparent variation in antimicrobial use.

Conclusions:

• Indirect standardization adjusts for case mix, reducing observed variation in antimicrobial use among children's hospitals.
• This method provides more accurate, adjusted comparisons, which can inform and enhance antimicrobial stewardship interventions.
• Implementing indirect standardization can lead to more effective strategies for optimizing antimicrobial prescribing in pediatric settings.