Re-infection after treatment for moderate and severe diabetic foot infections

Abstract

To investigate risk factors for re-infection and compare the outcomes in people with diabetic foot infections. A retrospective chart review was conducted, and 294 hospitalised patients with moderate to severe diabetic foot infections (DFIs) were analysed for this study. The diagnosis and classification of the severity of infection was based on the International Working Group on the Diabetic Foot (IWGDF) infection guidelines. Skin and soft tissue infections were diagnosed based on clinical observations as per IWGDF classification in addition to ruling out any suspected osteomyelitis (OM) through negative bone culture, MRI or WBC SPECT CT. OM was confirmed by bone culture or histopathology. Clinical outcomes were based on a 12-month follow-up period. All dichotomous outcomes were compared using χ² with an alpha of 0.05. The result of this study shows a 48% rate of re-infection in people admitted to our hospital with moderate and severe diabetic foot infections (DFI). Patients with osteomyelitis present during the index admission were 2.1 times more likely to experience a re-infection than patients with soft tissue infection (56.7% vs. 38.0% respectively). In the univariate analysis, risk factors for re-infection included osteomyelitis, non-healing wounds, prolonged wound healing, antidepressants and leukocytosis. In the regression analysis, the only risk factor for re-infection was wounds that were not healed >90 days (HR =2.0, CI: 1.5, 2.7, p = 0.001). Re-infection is very common in patients with moderate and severe diabetic foot infections. Risk factors include osteomyelitis, non-healing wound, prolonged wound healing, antidepressants and leukocytosis.