title: Outcome of inappropriate empirical antibiotic therapy in patients with Staphylococcus aureus bacteraemia: analytical strategy using propensity scores.
abstract: Patients with Staphylococcus aureus bacteraemia (SAB) who received either inappropriate or appropriate empirical therapy were compared by using two risk stratification models: (1) a cohort study using a propensity score to adjust for confounding by empirical treatment assignment; and (2) a propensity-matched case-control study. Inappropriate empirical therapy was modelled on the basis of patient characteristics, and included in the multivariate model to adjust for confounding. For case-matching analysis, patients with inappropriate empirical therapy (cases) were matched to those with appropriate empirical therapy (controls) on the basis of the propensity score (within 0.03 on a scale of 0-1). In total, 238 patients with SAB were enrolled in the cohort study. Characteristics associated with inappropriate empirical therapy were methicillin resistance, underlying haematological malignancy, no history of colonisation with methicillin-resistant S. aureus, and a long hospital stay before SAB. These variables were included in the propensity score, which had an area under the receiver operating characteristics curve of 85%. In the cohort study, SAB-related mortality was 39% (45/117) for inappropriate empirical therapy vs. 28% (34/121) for appropriate empirical therapy (odds ratio (OR) 1.60; 95% CI 0.93-2.76). After adjustment for independent predictors for mortality and the propensity score, inappropriate empirical therapy was not associated with mortality (adjusted OR 1.39; 95% CI 0.62-3.15). In the matched case-control study (50 pairs), SAB-related mortality was 32% (16/50) for inappropriate empirical therapy and 28% (14/50) for appropriate empirical therapy (McNemar's test; p 0.85; OR 1.15; 95% CI 0.51-2.64). In conclusion, inappropriate empirical therapy resulted in only a slight tendency towards increased mortality in patients with SAB.
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: S-H
authors.initials: SH
authors.lastname: Kim
authors.forename: W-B
authors.initials: WB
authors.lastname: Park
authors.forename: C-S
authors.initials: CS
authors.lastname: Lee
authors.forename: C-I
authors.initials: CI
authors.lastname: Kang
authors.forename: J-W
authors.initials: JW
authors.lastname: Bang
authors.forename: H-B
authors.initials: HB
authors.lastname: Kim
authors.forename: N-J
authors.initials: NJ
authors.lastname: Kim
authors.forename: E-C
authors.initials: EC
authors.lastname: Kim
authors.forename: M D
authors.initials: MD
authors.lastname: Oh
authors.forename: K-W
authors.initials: KW
authors.lastname: Choe
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D016470:Bacteremia / Q000188:drug therapy* / Q000382:microbiology / Q000401:mortality*; D015982:Bias; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008508:Medication Errors; D008875:Middle Aged; D015999:Multivariate Analysis; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology / Q000401:mortality; D013211:Staphylococcus aureus / Q000187:drug effects*; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents