[Impact of misuse of antimicrobial therapies on inpatient costs]

To evaluate the impact of inappropriate antibiotic use on inpatients' cost during hospitalization.

1 000 cases with antibiotic treatment were extracted from 10 hospitals of 5 provinces in China in 2005. We created multivariate linear regression model for hospital cost and Logistic regression model for evaluation of rationality in antibiotic use.

We collected 946 valid cases. Rate of inappropriate antibiotic use was 58.4%. Costs of inpatients with inappropriate antibiotic use was 1.55 times of the ones with appropriate use (P<0.001). Risk factors included antibiotic prophylaxis (OR=2.929), medication for surgery (OR=2.44), long hospital stay (OR=1.021 for every prolonged day) and regional factors. Protection factor was in tertiary hospital (OR=0.510).

Inappropriate antibiotic use could add 55% unnecessary cost on inpatients. Efforts to control misuse of antibiotics such as regulating antibiotic prophylaxis and medication for surgery, and decreasing length of stay should be pursued.