Outcome of diabetic foot infections treated conservatively: a retrospective cohort study with long-term follow-up

BACKGROUND: Diabetic foot lesion is associated with increased morbidity and high resource use. Although early amputation has been advocated in case of osteomyelitis, conservative treatment is a more attractive alternative. OBJECTIVE: To identify criteria predictive of failure of conservative treatment of diabetic foot ulcer at time of admission to the hospital. METHODS: We conducted a 5-year retrospective cohort study with prospective long-term follow-up of all diabetic patients admitted for a foot lesion at a large (1600-bed) teaching institution. Predetermined criteria were used for the diagnosis and classification of diabetic foot lesions (Wagner classification). Study variables included patient demographics and clinical parameters related to infection and diabetes. The average follow-up after hospital discharge was 2 years. Failure of conservative treatment was the main outcome measure. Independent predictor variables were selected by logistic regression analysis. RESULTS: A total of 120 diabetic patients were admitted for foot lesions; complications of contiguous osteomyelitis, deep tissue involvement, and/or gangrenous lesions occurred in 78 (74%) of the 105 patients for whom charts were available. Fourteen patients (13%) underwent immediate amputation. Conservative treatment was successful for 57 (63%) of the 91 remaining patients. Success was achieved in 21 (81%) of 26 patients presenting with skin ulcer, 35 (70%) of 50 patients with deep tissue infection or suspected osteomyelitis, and 1 (7%) of 15 patients with gangrene (P