119 Comparative Aggregate and Class-Specific Antimicrobial Utilization in 13 Intensive Care Units from 4 Teaching Hospitals: Results of the CDC Prevention Epicenters Antimicrobial Use Study Group

Friday, March 19, 2010
Grand Hall (Hyatt Regency Atlanta)
David Schwartz, MD , Stroger Hospital Of Cook County, Chicago, IL
R. Scott Evans, Ms, PhD, FACMI , University of Utah, Salt Lake City, UT
Bernard Camins, MD , Washington University School of Medicine, St. Louis, MO
Yosef Khan, MBBS, MPH , The Ohio State University Medical Center, Columbus, OH
Kurt Stevenson, MD , Ohio State Medical Center, Columbus, OH
James F. Lloyd, BS , University of Utah, Salt Lake City, UT
Julie L. Freshwater, BA, MPH , The Ohio State University Medical Center, Columbus, OR
Background: Little is known about antimicrobial utilization (AU) rates or the magnitude of variation in AU between intensive care units (ICUs) in American hospitals.

Objective: To program electronic hospital pharmacy and administrative data to derive validated measures of variation in AU among 13 selected ICUs in 4 teaching hospitals over a 36-month study period.

Methods: Queries of electronic pharmacy and administrative data stored in institutional data warehouses were developed, executed and carefully validated separately at each institution, with de-identified rate data compiled and analyzed centrally.  All anti-bacterial and antifungal drugs administered systemically were divided into 9 antimicrobial classes.  Aggregate AU measures included antimicrobial days (ADs: the sum of calendar days on which ICU patients received each antimicrobial; 2 drugs given for 3 days generates 6 ADs) and patient-days on antimicrobials (PDAs: the sum of calendar days on which ICU patients received any antimicrobial; 2 drugs given for 3 days generates 3 PDAs) per 1000 ICU patient-days; class-specific AU data were expressed as ADs/1000 patient-days.

Results: Expressed as ADs/1000 patient-days, mean (SD) monthly aggregate AU rates ranged from 952 (112) to 1911 (161) in 5 medical-type ICUs (MICUs), from 1101 (119) to 2204 (183) in 5 surgical-type ICUs (SICUs), and from 394 (102) to 1492 (162) in 3 coronary care units (CCUs).  Most of this variation was explained by variation in the number of antimicrobial drugs used per PDA: 1.61 (0.13) to 2.51 (0.14) in MICUs, 1.43 (0.11) to 2.61(0.19) in SICUs and 1.47 (0.13) to 2.34 (0.15) in CCUs; variation in PDAs/1000 patient-days was much lower.  Class-specific AU variation, expressed as ADs/1000 patient-days, was highest among anti-MRSA drugs: 132 (29) to 481 (71) in  MICUs, 182 (49) to 417 (63) in SICUs and 72 (29) to 384 (63) in CCUs.

Conclusions: We observed greater than 2-fold variation in AU rates among similar ICU types in 4 teaching hospitals.  These differences were accounted for more by variation in the number of antimicrobial drugs used per day of therapy than in the number of days of therapy themselves, and more by variation in rates of anti-MRSA drug use than in any other antimicrobial drug class.  The sources of this variation warrant investigation to identify potentially inappropriate antimicrobial prescribing practices amenable to intervention.