ANTIMICROBIAL UTILIZATION PATTERN IN A HEMATOLOGIC INTENSIVE CARE UNIT
Norberto Krivoy and Nurith Mattalon

BACKGROUND: Recently, a new method for assessing the quality of prescription — the drug utilization 90% index (DU-90%) — was introduced. The defined daily dose (DDD) concept is an established parameter in pharmacoepidemiologic studies.

OBJECTIVE: To evaluate antibiotic utilization in a specialized hospital unit where the use of antibiotics in immune-compromised patients undergoing intensive chemotherapy or bone marrow transplantation may be one of the main components in the direct cost of therapy of this type of patient.

METHODS: The antibiotic utilization pattern and accompanying costs were prospectively measured for 48 patients in a hematologic intensive care unit during a 60-day period, accumulating 896 admission days of follow-up. The DU-90% level is arbitrarily chosen as a reasonable cutoff point; it concentrates on the bulk of the prescribed antibiotics.

RESULTS: Of 26 antimicrobial agents prescribed, 14 were included in the DU-90%. Amphotericin B was delivered to 100% of the study population, with a total of 57.99 DDD/100 admission days. Ceftriaxone was the antimicrobial least prescribed, with a total of 0.22 DDD/100 admission days. The DU-90% index showed that 53% of the prescribed medications equal 92% of the total antibiotic cost. A discrepancy between the pharmacy's report and the calculated costs based on DDDs was observed. Failure to have a real-time inventory and costs unification, the use of mean instead of median acquisition costs, and failure to use electronic prescription systems are the main elements affecting and disrupting drug utilization studies. This possibly explains, in part, the difference between the two cost reports.

J Pharm Technol 2001;17:15-8.