Extended leg infection of diabetic foot ulcers: risk factors and outcome

Objective: To identify the risk factors for extension of infection to the leg in diabetic foot ulcers (DFU) and to evaluate its role as a prognostic measure regarding limb salvage and healing time. Method: This retrospective case-control study took place in Jabir Abu Eliz Diabetic (JADC) during 2006-2008. Forty-eight patients diagnosed with a diabetic foot ulcer (DFU) with the infection extending to the leg (case group) were compared with an equal number of patients with a DFU without extension (control group). Risk factors for extension were identified by univariate analysis and both groups were compared with regard to limb salvage and healing time. Results: Previous history of toe amputation was more frequent in the case group (p=0.004). The case group patients were significantly more likely to present with fever (p=0.01), pallor (p=0.02), confusion (p=0.04), and necrosis (p=0.004). Ulcers located in the heel were more frequent in the case group when compared with controls (p=0.0001) while more toes ulcers were found in the control group (p=0.001). A significant number of patients in the case group had an ulcer of more than 5cm diameter compared with those in the control group (p=0.001). The total number of patients presented with severe disease (Wagner grade 3-5) was significantly more in the case group compared with controls (p=0.004). Patients with severe infection (grade 4) were more in the case group compared with the controls (p=0.04). There were no significant differences between the two groups with regard to major and minor amputation rate. The case group had a longer duration of healing when compared with the controls. Seventy-five per cent of the controls healed by 6 months (n=31) compared with 22% in the case group (n=8; p=0.001). Conclusion: Toe amputation,wound located in the heel, wound size more than 5cm and advanced Wagner grade (3-5) and severe sepsis, grade 4, may be considered as risk factors for extension of infection to the leg in DFU. However, this extension did not carry a poor prognostic value to the final outcome if adequate therapeutic measures were followed. Conflict of interest: None.