Shey-Ying Chen1,2, John M Giurini3, Adolf W Karchmer4. 1. Division of Infectious Diseases, Department of Medicine, and. 2. Department of Emergency Medicine, National Taiwan University Hospital, College of Medicine, Taipei. 3. Division of Podiatry, Department of Surgery, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts. 4. Division of Infectious Diseases, Department of Medicine, and akarchme@bidmc.harvard.edu.
Abstract
BACKGROUND: Diabetic foot ulcers (DFUs) threaten limbs and prompt hospitalization. After hospitalization, remote-site invasive systemic infection related to DFU (DFU-ISI) may occur. The characteristics of DFU-ISIs and their effect on mortality risk have not been defined. METHODS: We conducted a retrospective cohort study of 819 diabetic patients hospitalized for treatment of 1212 unique DFUs during a 9-year period. We defined the index ulcer as that present at the first (index) DFU admission to our hospital. We defined DFU-ISI as a nonfoot infection that occurred after the index hospitalization and was caused by a microorganism concomitantly or previously cultured from the index ulcer. We determined the frequency, risk factors, and mortality risk associated with DFU-ISIs. RESULTS: After 1212 index DFU hospitalizations, 141 patients had 172 DFU-ISIs. Of the initial 141 DFU-ISIs, 64% were bacteremia, 13% deep abscesses, 10% pneumonia, 7% endocarditis, and 6% skeletal infections. Methicillin-resistant Staphylococcus aureus (MRSA) caused 57% of the ISIs. Patients with initial DFU cultures yielding MRSA and protracted open ulcers had a high 24-month cumulative probability of DFU-ISI (31%) and all-cause mortality rate (13%). Analysis with Cox regression modeling showed that complicated ulcer healing (hazard ratio, 3.812; 95% confidence interval, 2.434-5.971) and initial DFU culture yielding MRSA (2.030; 1.452-2.838) predicted DFU-ISIs and that DFU-ISIs were associated with increased mortality risk (1.987; 1.106-3.568). CONCLUSIONS: DFU-ISIs are important late complications of DFUs. Prevention of DFU-ISIs should be studied prospectively. Meanwhile, clinicians should aggressively incorporate treatment to accelerate ulcer healing and address MRSA into the care of diabetic patients with foot ulcers.
BACKGROUND:Diabetic foot ulcers (DFUs) threaten limbs and prompt hospitalization. After hospitalization, remote-site invasive systemic infection related to DFU (DFU-ISI) may occur. The characteristics of DFU-ISIs and their effect on mortality risk have not been defined. METHODS: We conducted a retrospective cohort study of 819 diabeticpatients hospitalized for treatment of 1212 unique DFUs during a 9-year period. We defined the index ulcer as that present at the first (index) DFU admission to our hospital. We defined DFU-ISI as a nonfoot infection that occurred after the index hospitalization and was caused by a microorganism concomitantly or previously cultured from the index ulcer. We determined the frequency, risk factors, and mortality risk associated with DFU-ISIs. RESULTS: After 1212 index DFU hospitalizations, 141 patients had 172 DFU-ISIs. Of the initial 141 DFU-ISIs, 64% were bacteremia, 13% deep abscesses, 10% pneumonia, 7% endocarditis, and 6% skeletal infections. Methicillin-resistant Staphylococcus aureus (MRSA) caused 57% of the ISIs. Patients with initial DFU cultures yielding MRSA and protracted open ulcers had a high 24-month cumulative probability of DFU-ISI (31%) and all-cause mortality rate (13%). Analysis with Cox regression modeling showed that complicated ulcer healing (hazard ratio, 3.812; 95% confidence interval, 2.434-5.971) and initial DFU culture yielding MRSA (2.030; 1.452-2.838) predicted DFU-ISIs and that DFU-ISIs were associated with increased mortality risk (1.987; 1.106-3.568). CONCLUSIONS: DFU-ISIs are important late complications of DFUs. Prevention of DFU-ISIs should be studied prospectively. Meanwhile, clinicians should aggressively incorporate treatment to accelerate ulcer healing and address MRSA into the care of diabeticpatients with foot ulcers.