Predictors of lower extremity amputation in patients with diabetic foot ulcer: findings from MEDFUN, a multi-center observational study

Abstract

Background: Lower extremity amputation (LEA) is a potential sequelae of diabetic foot ulceration (DFU) and is associated with huge morbidly and mortality. Low and middle income countries are currently at the greatest risk of diabetes-related complications and deaths. We sought to identify demographic, clinical and laboratory variables that significantly predict LEA in patients hospitalized for DFU.

Methods: The Multi-center Evaluation of Diabetic Foot Ulcer in Nigeria (MEDFUN) was an observational study conducted between March 2016 and April 2017 in six tertiary healthcare institutions. We prospectively followed 336 diabetic patients hospitalized for DFU and managed by a multidisciplinary team until discharge or death. Demographic and diabetes-related information and ulcer characteristics were documented. Patients were evaluated for neuropathy, peripheral arterial disease (PAD) and medical co-morbidities while relevant laboratory and imaging tests were performed. The study end-points were ulcer healing, LEA, duration of hospitalization and mortality. Here we present data on amputation.

Results: One hundred and nineteen subjects (35.4%) underwent LEA during the follow-up period. Univariate predictors of LEA were ulcer duration more than 1 month prior to hospitalization (P < 0.001), PAD (P < 0.001), Wagner grade ≥ 4 (P < 0.001), wound infection (P 0.041), Proteinuria (P 0.021), leucocytosis (P 0.001) and osteomyelitis (P < 0.001). On multivariate regression, only three variables emerged as significant independent predictors of LEA and these include: ulcer duration more than 1 month (O.R. 10.3, 95% C.I. 4.055-26.132), PAD (O.R. 2.8, 95% C.I. 1.520-5.110) and presence of osteomyelitis (O.R. 5.6, 95% C.I. 2.930-10.776). Age, gender, diabetes type and duration, neuropathy, glycemic control and anemia did not predict LEA in the studied population.

Conclusion: We identified duration of ulcer greater than 1 month, PAD, Wagner grade 4 or higher, proteinuria, leucocytosis, wound infection and osteomyelitis as the significant predictors of LEA in patients hospitalized for DFU. Prompt attention to these risk factors may reduce amputation rate among these patients.

Keywords: Africa; Amputation; Diabetes; Foot ulcer; MEDFUN; Nigeria; Predictors; Risk factors.