Invasive Systemic Infection After Hospital Treatment for Diabetic Foot Ulcer: Risk of Occurrence and Effect on Survival

Clin Infect Dis. 2017 Feb 1;64(3):326-334. doi: 10.1093/cid/ciw736. Epub 2016 Nov 10.

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.

Keywords: diabetes mellitus; foot ulcer; methicillin resistant Staphylococcus aureus; mortality.; systemic infection.

MeSH terms

  • Abscess / epidemiology
  • Abscess / microbiology
  • Abscess / mortality
  • Aged
  • Bacteremia / epidemiology
  • Bacteremia / microbiology
  • Bacteremia / mortality
  • Bone Diseases, Infectious / epidemiology
  • Bone Diseases, Infectious / microbiology
  • Bone Diseases, Infectious / mortality
  • Cohort Studies
  • Diabetic Foot / drug therapy
  • Diabetic Foot / epidemiology
  • Diabetic Foot / microbiology*
  • Diabetic Foot / mortality*
  • Endocarditis, Bacterial / epidemiology
  • Endocarditis, Bacterial / microbiology
  • Endocarditis, Bacterial / mortality
  • Female
  • Hospitalization
  • Humans
  • Incidence
  • Length of Stay
  • Male
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification*
  • Middle Aged
  • Pneumonia, Bacterial / epidemiology
  • Pneumonia, Bacterial / microbiology
  • Pneumonia, Bacterial / mortality
  • Retrospective Studies
  • Risk Factors
  • Severity of Illness Index
  • Staphylococcal Infections / complications
  • Staphylococcal Infections / epidemiology
  • Staphylococcal Infections / microbiology*
  • Staphylococcal Infections / mortality*