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

Abstract

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. Retrospective cohort study. University-affiliated general hospital. A cohort of 168 CRE carriers with 474 readmissions. 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. 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. CRE carrier state commonly persists upon readmission, and this risk can be estimated to guide screening policy and infection control measures.