Original Research

Factors Associated With Lower-Extremity Amputation in Patients With Diabetic Foot Ulcers




Of the 169 registered patients treated at the Northwell Health facility, all qualified for the OWEMR study and met the study criteria. In the original 169 patients, there were 19 amputations: 6 toe, 6 trans-metatarsal, 6 below knee, and 1 above knee (Table 1).

Descriptive Statistics of Study Patients

The descriptive statistics of 149 patients grouped into 3 categories (healed, amputated, unhealed/non-amputated) are shown in Table 2.

Characteristics of Patients at 3-Month Follow-up

The results of the logistic regression exploring the differences between the amputation and healed groups and the unhealed/non-amputated group are shown in Table 3. The amputation group had a higher mean age and WBC count and greater wound area. Increased age was determined to be a significant predictor of the odds of amputation (P = 0.0089). For each year increase in age, the odds of amputation increased by 6.5% (odds ratio, 1.07 [95% confidence interval {CI}, 1.02-1.12]). Patients in the amputation group were more likely to be male, Hispanic, and African American and to have wound infections and comorbidities (osteomyelitis, neuropathy, and gangrene).

Results of Multinomial Logistic Regression Examining Differences Between Amputation Versus Unhealed/Non-amputated Groups and Healed Versus Unhealed/Non-amputated Groups (n = 149)

The presence of gangrene was significantly associated with LEA (P = 0.03). Specifically, the odds of patients without gangrene undergoing a LEA were substantially lower compared with their counterparts with gangrene (odds ratio, 0.17; 95% CI, 0.04-0.68; P = 0.0131). However, the presence of gangrene was not associated with the odds of healing compared with the odds of neither healing nor undergoing amputation (P = 0.84; not shown in Table 3).

The amputation group had lower mean values for HbA1c, BMI, and blood glucose levels and a lower rate of peripheral vascular disease. Only the relationship between lower HbA1c and increased odds of amputation versus not healing/non-amputation was found to be statistically significant (95% CI, 0.27-0.78; P = 0.009).


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