Risk Factors for Amputation in Patients with Diabetes Mellitus

TLDR

The study aims to identify and quantify risk factors for lower‑extremity amputation in individuals with diabetes mellitus. A case‑control study at a Veterans Affairs medical center enrolled 80 amputated diabetic patients and 236 diabetic controls, assessing vascular, neuropathic, environmental, and psychosocial factors before surgery and outlining interventions such as aggressive infection treatment, diabetes education, protective footwear, and preventive foot care. Significant predictors of amputation were insufficient below‑knee circulation, ankle‑arm index <0.45, loss of lower‑leg vibratory perception, low HDL subfraction 3, and absence of prior diabetes education, with logistic regression confirming these associations and suggesting that modifying these factors could reduce amputation risk and associated costs.

Abstract

Objective: To identify and quantify risk factors for lower extremity amputation in persons with diabetes mellitus. Design: Case-control study. Setting: A Veterans Affairs medical center. Patients: Eighty patients having amputation associated with diabetes and 236 diabetic controls without limb lesions were enrolled before surgery from the 21 167 inpatient care and outpatient surgical patients seen at the Seattle Veterans Affairs Medical Center during a 30-month period. Measurements: Selected vascular, neuropathic, environmental, health care, self care, nutritional, metabolic, lifestyle, and psychosocial risk factors were measured in all patients before surgery. Results: Statistically significant risk factors identified from analysis included insufficient mean below-knee and foot cutaneous circulation (odds ratio, 161; 95% Cl, 55.1 to 469); ankle-arm blood pressure index < 0.45 (odds ratio, 55.8; Cl, 14.9 to 209); absence of lower leg vibratory perception (odds ratio, 15.5; Cl, 8.3 to 28.7); low levels of high-density lipoprotein (HDL) subfraction 3 ≤ 0.7 µmol/L (odds ratio, 4.9; Cl, 2.9 to 8.3); and no previous outpatient diabetes education (odds ratio, 3.2; Cl, 1.6 to 6.6). A logistic regression analysis done to control for the potentially confounding effects of age; race; socioeconomic status; diabetes duration, type, and severity confirmed these findings and added a statistically significant interaction between foot transcutaneous oxygen tension and peripheral vascular disease history. Clinical interventions to alter these risk factors were identified, including aggressive treatment of infection, diabetes education, protective footwear, and preventive footcare. Conclusions: Multiple risk factors exist along the continuum of conditions and events leading to lower extremity amputation in diabetes. Modification of certain risk factors by patients and health professionals may reduce the risk for amputation and thus decrease the human and dollar costs that accompany limb loss in this prevalent chronic disease.