Mortality in patients with diabetic foot ulcer: A retrospective study of 513 cases from a single Centre in the Northern Territory of Australia

Background: Diabetic foot ulcers (DFU) are a common problem in longstanding diabetes. However, mortality outcomes in Australian patients with DFU are still unclear.

Methods: All patients with DFU presenting for the first time to the Multi-Disciplinary Foot Clinic (MDFC) at Royal Darwin Hospital, Northern Territory Australia, between January 2003 and June 2015 were included in this study. These patients were followed until 2017, or death. Individual patient data was extracted from hospital and primary care information systems. Kaplan-Meier survival curves were developed. The association between various risk factors and mortality was analysed using Cox regression.

Results: In total 666 subjects were screened, and 513 were included in the final analysis. Of these subjects, 247 were Indigenous and 266 were non-Indigenous. The median follow-up period was 5.8 years (IQR, 3.1-9.8). The mean age at inclusion was 59.9 ± 12.3 years and 62.8% were males. The majority (93.6%) had type 2 diabetes and the median diabetes duration was 7 years (IQR, 3-12). There were 199 deaths, with a 5-year-mortality rate of 24.6%, and a 10-year-mortality rate of 45.4%. The mean age at death was 64.6 ± 11.8 years. In a multivariate analysis, the following variables were associated with mortality (adjusted HR, 95% CI): age 1.04 (1.02-1.05, P < 0.001); chronic kidney disease 1.22 (1.11-1.33, P < 0.001), and plasma albumin 0.96 (0.94-0.99, P < 0.05). The most common causes of death were chronic kidney disease (24.6%), cardiovascular events (19.6%), sepsis (15.6%), respiratory failure (10.0%), malignancy (9.5%) and multi-organ failure (5.0%).

Conclusion: Patients with DFU have high mortality. Age, chronic kidney disease, and low albumin levels increase the risk of mortality. Strategies should focus on ulcer prevention and aggressive risk factor reduction.