Risk factors for lower extremity amputation in diabetic foot disease categorized by Wagner classification

Aims: To elucidate the risk factors for lower extremity amputation (LEA) in patients of diabetic foot disease with different Wagner gradings.

Methods: This study was conducted in a multidisciplinary diabetic foot care center. Demographic characteristics, laboratory data, disease history, ankle brachial pressure index (ABI) and Wagner classification were considered as independent variables to predict the therapeutic outcome (major LEA, minor LEA, and non-amputation). Risk factors for LEA in different Wagner grades were further analyzed. Multivariate stepwise ordinal logistic regression was performed.

Results: Of 789 study subjects, 19.9% received major LEA and 22.9% received minor LEA. Higher Wagner grade, lower ABI, serum albumin and hemoglobin, and elevated white blood cell (WBC) count were significantly associated with an increased risk of LEA. When stratified by Wagner classification, most of the above predictors and estimated glomerular filtration (eGFR) were detected only in grade 3. While in grades 2 and 4, WBC count was identified as primary predictor positively associated with an increased risk of LEA.

Conclusions: Wagner classification remarkably influenced the potential risk factors for LEA, showing different predictors in different grades. The traditionally recognized predictors for diabetic foot amputation such as lower ABI, albumin or eGFR were almost exclusively found in patients with Wagner grade 3.