Risk factors of lower extremity amputation in diabetic foot ulcer patients: a hospital based case-control study

Abstract

Background: Diabetic foot ulcers have reached epidemic proportions, and constitute significant public health and economic burden for health systems worldwide. The global prevalence of diabetic foot ulcers demonstrates considerable variation with a pooled prevalence of 6.3%. Lower extremity amputations are among the most severe and life-threatening health complications of diabetic foot, leading to reduced quality of life and increased medical costs. Diabetes-related foot ulcerations remain the principal cause of non-traumatic lower extremity amputations worldwide. Objectives: The study sought to identify the risk factors associated with amputation in diabetic foot ulcer patients as well as to identify the risk factors associated with major amputation in patients with diabetes-related amputations in Armenia. Methods: A case-control study design was utilized involving patients admitted to Armenia Medical Center and Erebouni Medical Center during the year of 2018. Cases were defined as patients who were admitted to the medical center and underwent minor or major lower extremity amputation. Controls were patients who had diabetes-related hospitalization and treatment with coexisting diabetic foot ulcer. Data on 52 potential risk factors were collected from the patients via telephone interviews and medical records reviews. To assess the strength of the association between the potential risk factors and lower extremity amputation simple and stepwise multiple logistic regression analyses were conducted. Results: The study comprised 77 cases and 77 controls. Simple logistic regression analysis revealed statistically significant differences between LEA and DFU groups in 7 out of 52 potential risk factors. In a stepwise multiple logistic analysis, three (age 51-60 years (OR=17.86; 95% CI: 1.57-202.28) vs. ˂50 years, age >70 years (OR=68.58: 95% CI: 5.08-924.66) vs. ˂50 years, history of diabetic foot ulcer (OR=123.24; 95% CI: 13.15-1154.65) and total leukocyte count (OR=1.37; 95% CI: 1.15-1.64)) of the 7 risk factors remained significant. Similarly, statistically significant differences between major LEA and minor LEA groups were observed in diabetes treatment involving insulin therapy combined with oral agents and diet (OR=0.02; 95% CI: 0.0009-0.48), total leukocyte count (OR=1.19; 95% CI: 1.05-1.35) and fasting plasma glucose levels (OR=0.85; 95% CI: 0.76-0.96). Conclusion: The risk factors of lower extremity amputation among hospitalized diabetic foot ulcer patients were age, history of foot ulcer and total leukocyte count. Additionally, the risk factors of major LEA among patients with diabetes-related LEA were diabetes treatment, total leukocyte count and fasting plasma glucose.