Antimicrobial misuse in patients with positive blood cultures.
OBJECTIVE
Inappropriate antimicrobial use was examined among a randomly and prospectively selected cohort of patients with at least one positive result of blood cultures. This misuse was then analyzed with respect to hospital charges and length of stay (LOS).


METHODS
The study consisted of 70 patients (average age, 58.5 years) who had not undergone bone marrow transplantation. Patient charts were reviewed daily for the following information: clinical signs and symptoms of infection, pertinent laboratory data, culture results, detailed data on each antimicrobial in every antimicrobial regimen and their appropriateness, hospital charges, LOS, diagnostic and procedure codes, and discharge status. Three severity of illness variables were generated. Inappropriate antimicrobial use was described according to one of 12 categories.


RESULTS
The percent of antimicrobial misuse, defined as the proportion of days of administration of antimicrobials on which one or more antimicrobials were judged inappropriate, was found to be 22.3%. After adjustment for severity of illness and diagnosis, this average inappropriateness correlated with 4.2 additional hospitalization days and $5,368 additional hospital charges.


CONCLUSIONS
Our results cannot distinguish among several possible reasons for these associations, including direct causality (e.g., toxicity and prolonged hospitalization for antimicrobial use) and indirect links such as inappropriate utilization of other resources and influences of severity of illness on antimicrobial use not accounted for in our equations. Nevertheless, the magnitude of the association gives import to the desirability of further studies.
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.
W C
WC
Dunagan
R S
RS
Woodward
G
G
Medoff
J L
JL
Gray
E
E
Casabar
M D
MD
Smith
C A
CA
Lawrenz
E
E
Spitznagel
D000890:Anti-Infective Agents / Q000008:administration & dosage*; D015331:Cohort Studies; D003365:Costs and Cost Analysis; D003422:Critical Care / Q000191:economics; D004334:Drug Administration Schedule; D004363:Drug Utilization / Q000191:economics*; D004469:Economics, Hospital; D005260:Female; D006801:Humans; D007239:Infections / Q000188:drug therapy*; D007902:Length of Stay / Q000191:economics; D008297:Male; D008875:Middle Aged; D008923:Missouri; D011446:Prospective Studies; D011897:Random Allocation; D012720:Severity of Illness Index
D000890:Anti-Infective Agents