High Rates of Multidrug Resistance in Diabetic Foot Infection in Detroit Area: Does It Matter?

Abstract

Background. Multidrug-resistant organisms (MDROs) are important diabetic foot infection (DFI) pathogens. This study evaluated the impact of DFI due to MDROs (MDRO-DFI) on clinical outcomes. Methods. Adults admitted to Detroit Medical Center from 1/2012 to 12/2015 with culture-positive DFI were included. Associations between outcomes and MDRO-DFI (evaluated as a single group that included methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci, Enterobacteriaceae-resistant to third-generation cephalosporins and/or carbapenems (Enterobacteriacae-R), Acinetobacter baumannii, and Pseudomonas aeruginosa) were analyzed. Outcomes included above and below knee lower extremity amputation (LEA) and readmissions and mortality within a year following DFI. A propensity score predicting the likelihood of having MDRODFI was computed by comparing patients with MDRO-DFI to patients with DFI not due to MDROs (non-MDRO-DFI). A conditional logistic model was constructed for each outcome, and MDRO-DFI was analyzed as an independent variable after patients in the MDRO and non-MDRO groups were matched by propensity score. Results. 674 patients were included, with a mean age of 58.6 ± 13.8. Sixtyfour percent were male and 73% African American. Median Charlson score was 7 (IQR 5-9). Most patients (n = 394, 59%) had MDRO-DFI and MRSA was the most common (235, 60% of MDRO-DFI patients), followed by P. aeruginosa (25%) and Enterobacteriaceae-R (15%). In bivariate analyses LEA and 1 year readmission were more common in the MDRO-DFI group (Table). However, in propensity-adjusted analyses, MDRO-DFI was no longer associated with LEA or hospital readmission. Conclusion. LEA occurred in > 20% of DFI-MDRO patients, and >60% of patients were readmitted to the hospital within a year following a DFI-MDRO episode. In propensity-adjusted analyses, DFI-MDRO was not significantly associated with these clinical outcomes. Table: Impact of DFI-MDRO on outcomes.