Amputations in patients with diabetic foot ulcer: a retrospective study from a single centre in the Northern Territory of Australia

Background: Lower extremity amputations (LEAs) in diabetic patients are common in the indigenous population. There is no published data from the Northern Territory.

Methods: All patients with diabetic foot ulcer, presenting for the first time to the multi-disciplinary foot clinic at Royal Darwin Hospital, between January 2003 and June 2015, were included. These patients were followed until 2017, or death. LEA rates over the follow-up period and the risk factors were studied.

Results: Of the 513 included patients, 62.8% were males and 48.2% were indigenous. The majority (93.6%) had type 2 diabetes with median diabetes duration of 7.0 years (interquartile range 3-12). During the follow-up period of 5.8 years (interquartile range 3.1-9.8), a total of 435 LEAs (16.6% major; 34.7% minor) occurred in 263 patients (mean age 57.0 ± 11.8 years). In multivariate analysis, the following variables were associated with LEAs (adjusted odds ratio (95% confidence interval)): prior LEA (4.49 (1.69-11.9)); peripheral vascular disease (2.67 (1.27-5.59)); forefoot ulcer (7.72 (2.61-22.7)); Wagner grade 2 (3.71 (1.87-7.36)); and Wagner grade 3 (17.02 (3.77-76.72)). Indigenous patients were 1.8 times more likely to have LEAs than non-indigenous patients. Indigenous amputees were approximately 9 years younger than their non-indigenous counterparts.

Conclusion: Half of patients presenting with diabetic foot ulcer had LEA during follow-up. Prior LEAs, peripheral vascular disease, forefoot ulcers and higher Wagner grades were independent risk factors for LEA. Indigenous patients were at higher risk for LEAs and were younger at the time of amputation.