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

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.

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.

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).

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.