Predicting Outcomes in Patients with Diabetic Foot Ulcers

This thesis aims to expand the knowledge about the natural history, predictive factors of key outcomes and management of diabetic patients with foot ulcers. In Chapter 1 we present a broad review of the topic emphasising the pathophysiology and principles of management of the diabetic foot. It has been published as a chapter of the book “Mechanisms of Vascular Disease: A reference book for Vascular Specialists”. This is a core text for Vascular Training in Australasia. The subsequent chapters are a series of published manuscripts covering different topics associated with diabetes-related foot disease. In Chapter 2 we present a review exploring the differences in presentation, anatomy of vascular disease and outcomes of treatment of chronic lower limb threatening Ischaemia between diabetic and non-diabetic patients. Chapter 3 describes both the burden of lower limb amputation (minor and major) in Australia and New Zealand using the Australasia Vascular Audit (AVA) database and the financial costs of diabetic patients undergoing amputations in our institution. The following research gaps were identified during the literature review process and were factored into the research design: (1) Lack of standardisation in assessment of foot wounds. Assessment of wounds is an integral part of assessment of patients with diabetic foot disease. Having a method of objective wound assessment is especially important when performing research involving wound management. We were aware of a prototype device (WoundVue® camera) that was developed by the machine learning department at The University of Adelaide in collaboration with a local technology company - LBT Innovations Limited (Adelaide, South Australia). We proposed to validate the WoundVue® for assessment of diabetic foot wounds. Research question: Is the WoundVue camera capable of reliably assessing foot wounds in diabetic patients? (2) Lack of information about prevalence of micronutrient deficiency in the diabetic foot population. Anecdotal data from patients seen at the foot clinic at the Queen Elizabeth hospital suggested that a high prevalence of mineral and vitamin deficiency exists in this population. Research question: What is the prevalence of micronutrient deficiency in diabetic patients with foot ulcers? (3) Paucity of prospective research assessing factors associated with key outcomes in diabetic foot disease. A new classification system for threatened limbs was proposed in 2014 by the Society for Vascular Surgery and provides a comprehensive assessment of limb status. This classification, named WIfI, is particularly applicable to diabetic patients with foot ulcers and therefore was endorsed by the International Working Group on the Diabetic Foot. Despite multiple researchers using this WIfI classification, there were a lack of prospective trials assessing the value of this scoring system on assessment of patients with diabetic foot ulcers. We decided to include the WIfI system in the prospective trial assessing factors associated with negative outcomes in diabetic foot disease. Research question: What are the factors associated with risk of major amputation, mortality, wound healing completion and amputation free survival in diabetic foot disease? Chapters 4 to 6 address the aforementioned specific research questions. Chapter 4 describes a study using the WoundVue® system, which is a prototype device that uses the principles of stereophotogrammetry to provide a 3-dimensional assessment of wounds. The study showed that the WoundVue® camera is capable of providing accurate and reproducible wound measurements and it has the potential to be a valuable adjunct in diabetic foot wound care. We report in Chapter 5 the prevalence of micronutrient deficiencies in diabetic patients with foot ulcers. It is well known that micronutrients, such as vitamin C and zinc, have an important role in wound healing. However, micronutrient deficiencies are not commonly assessed in clinical practice for diabetic patients with foot ulcers. Knowing the prevalence of micronutrient deficiency could reveal a potential target for intervention. In Chapter 6 we present the results of a prospective observational study assessing factors associated with key outcomes in diabetic foot disease: namely major amputation, mortality, completion of wound healing and amputation-free survival. As part of this study, we have prospectively validated the WIfI classification system. Finally, in Chapter 7 we summarise the main findings of this thesis and discuss its implications for clinical practice and scientific research. The appendix chapters include the research baseline and follow up questionnaires; data dictionary and two published manuscripts about diabetic-related foot disease that G Pena contributed as co-author.

Author dc:creator

• Pena, Guilherme

Advisors dc:contributor.advisor

• Fitridge, Robert
• Cowled, Prue
• Dawson, Joseph

• Diabetes
• ulcers
• amputation

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/2440/134323

OAI identifier oai:identifier

oai:digital.library.adelaide.edu.au:2440/134323