Clinical characteristics, risk factors, and outcomes of patients hospitalized in the US military health system with carbapenem-resistant Enterobacteriaceae infection

Background: We aimed to characterize the epidemiology, identify risk factors, and measure outcomes of carbapenem-resistant Enterobacteriaceae (CRE) infections among hospitalized patients. Methods: We performed a retrospective study of hospitalized patients with CRE infection using records from the US military health system database. Cases included patients admitted for >= 2 days from 2008-2015, with a clinical culture growing any Enterobacteriaceae reported as resistant to a carbapenem. Multivariable logistic regression was used to identify comorbid conditions and procedures associated with CRE infection, and a high-dimensional propensity score was used for a case-mix adjusted evaluation of CRE-associated in-hospital mortality, length of stay, and hospitalization costs. Results: From 1,162,686 hospitalized patients, we identified 143 with CRE infection over the 7-year study period. Conditions associated with CRE infection included manipulation of the gastrointestinal tract, musculoskeletal trauma, orthopedic procedures, septicemia, and both recent and remote exposure to broad-spectrum beta-lactam antibiotics. Patients hospitalized with CRE infection had significantly higher hospitalization costs (attributable difference, $206,664; P<.001), longer hospital stays (attributable difference, 28.8 days; P<.001), and increased odds of in-hospital mortality (adjusted odds ratio, 3.34; 95% confidence interval, 1.82-6.12). Conclusions: CRE are a significant threat to hospitalized patients. Our study quantifies the health care burden associated with CRE infection in the inpatient setting and highlights the importance of initiatives aimed at curbing the spread of these costly infections. Published by Elsevier Inc. on behalf of Association for Professionals in Infection Control and Epidemiology, Inc.