Predictors of Persistent Carbapenem-Resistant Enterobacteriaceae Carriage upon Readmission and Score Development.

BACKGROUND: Carriers of carbapenem-resistant Enterobacteriaceae (CRE) are often readmitted, exposing patients to CRE cross-transmission. OBJECTIVE To identify predictors of persistent CRE carriage upon readmission, directing a risk prediction score.

DESIGN: Retrospective cohort study.

SETTING: University-affiliated general hospital.

PATIENTS: A cohort of 168 CRE carriers with 474 readmissions.

METHODS: The primary and secondary outcomes were CRE carriage status at readmission and length of CRE carriage. Predictors of persistent CRE carriage upon readmission were analyzed using a generalized estimating equations (GEE) multivariable model. Readmissions were randomly divided into derivation and validation sets. A CRE readmission score was derived to predict persistent CRE carriage in 3 risk groups: high, intermediate, and low. The discriminatory ability of the model and the score were expressed as C statistics.

RESULTS: CRE carrier status persisted for 1 year in 33% of CRE carriers. Positive CRE status was detected in 202 of 474 readmissions (42.6%). The following 4 variables were associated with persistent CRE carriage at readmission: readmission within 1 month (odds ratio [OR], 6.95; 95% confidence interval [CI], 2.79-17.30), positive CRE status on preceding admission (OR, 5.46; 95% CI, 3.06-9.75), low Norton score (OR, 3.07; 95% CI, 1.26-7.47), and diabetes mellitus (OR, 1.84; 95% CI, 0.98-3.44). The C statistics were 0.791 and 0.789 for the derivation set (n=322) model and score, respectively, and the C statistic was 0.861 for the validation set of the score (n=152). The rates of CRE carriage at readmissions (validation set) for the groups with low, intermediate, and high scores were 8.6%, 38.9%, and 77.6%, respectively.

CONCLUSIONS: CRE carrier state commonly persists upon readmission, and this risk can be estimated to guide screening policy and infection control measures.