Risk factors for primary major amputation in diabetic patients.

CONTEXT AND OBJECTIVE Diabetic patients present high risk of having to undergo minor or major amputation during their lifetimes, because of ischemia or infection. The aim of this study was to identify and quantify risk factors for major amputation in diabetic patients with foot infections. DESIGN AND SETTING Retrospective clinical-surgical trial at the Vascular Surgery Service of Santa Casa de São Paulo. METHODS Ninety-nine patients with diabetic foot infections who underwent 129 hospitalizations in the Vascular Surgery Unit were analyzed in accordance with a pre-established protocol to compare two groups of diabetic patients: one that underwent major amputations and the other that underwent minor amputations or debridements. The patients were predominantly male, in their sixth decade of life, and had type 2 diabetes mellitus. Chronic arterial insufficiency, age, diabetes mellitus duration, ascending lymphangitis, calcaneal lesions, Wagner's classification, laboratory tests and different microorganisms in deep tissue cultures were the risk factors evaluated in all patients. RESULTS The statistically significant risk factors for major amputation included age, ascending lymphangitis (odds ratio, OR: 2.5), calcaneal lesions (OR: 10.5), Wagner grade 5 lesions (OR: 3.4), chronic arterial insufficiency without possibility of revascularization (OR: 5.4) and diabetes duration. Presence of Gram-positive microorganisms was associated with the need of major amputation. The serum urea, creatinine, glucose and white blood cell levels were not significant risk factors for major amputation. CONCLUSIONS The risk factors for major amputation were: age, ascending lymphangitis, calcaneal lesions, Wagner grade 5 lesions, arterial insufficiency, diabetes duration and Gram-positive microorganisms in cultures.