Predictive factors for major amputation of lower limb in diabetic foot: about 430 patients.

Background: Major amputation of the lower limb is defined by a leg or thigh amputation. The aim of our work was identifying predictive factors for lower limb major amputation in patients with diabetes admitted on for foot lesions through using an administrative data base.

Methods: It was a retrospective study ranging from June 1st, 2008 to December 31st, 2011, which included all the patients admitted on for an infected diabetic foot to the surgery unit B of Charles Nicolle hospital in Tunis. The main judgement criterion was the major amputation of the lower limb. We have done a descriptive and a comparative study, with univariate and multivariate analysis.

Results: We have enrolled 319 men and 111 women. The average age was 60.5 ± 12 years. Ninety five patients (24%) had a major amputation. Former inpatient, patient readmitted within one month post-operatively, stay in intensive care, admission in intensive care within 48hours after admission, age ≥ 65 years, presence of kidney problem, preoperative stay and length of intervention were identified as predictive factors of major amputation in the univariate analysis. Age was the only independent variable predictive for major amputation which appeared from the multivariate analysis (p=0.004).  The age cut-off ≥ 65 years has a specificity of 69 % and a sensitivity of 47% [p=0.004, OR=1.971, IC 95% : 1.239-3.132].

Conclusions: Age was the only independent predictive factor for major amputation of the lower limb in the diabetic foot with a threshold value higher or equal to 65 years. Patients aged more than 65 had 1.9 time more risk to undergo major amputation of the lower limb.