Protocol for a prospective observational study: the Australia and New Zealand Diabetic and Ischaemic Foot Outcomes Study (ANZ-DIFOS)

Diabetic foot disease is a common condition globally and is over-represented in indigenous populations. The propensity for patients with diabetic foot disease to undergo minor or major limb amputation is a concern. Diabetic foot disease and lower limb amputation are debilitating for patients and have a substantial financial impact on health services. The purpose of this multicentre study is to prospectively report the presentation, management and outcomes of diabetic foot disease, to validate existing scoring systems and assess long term outcomes for these patients particularly in relation to major limb amputation.

This is a multisite, international, prospective observational study, being undertaken at Waikato Hospital, New Zealand (NZ); Sir Charles Gairdner Hospital, the Royal Adelaide Hospital and the Queen Elizabeth Hospital, Australia. Consecutive participants with diabetic foot disease that meet inclusion criteria and agree to participate will be recruited from multidisciplinary team diabetic foot clinic, vascular clinic, dialysis and admission to hospital. Follow-up of participants will occur at 1, 3, 6 and 12 months. At recruitment and follow-up reviews, information about service details, demographic and clinical history, wound data and discharge information will be recorded. The primary outcomes are the time to wound healing, major amputation, overall mortality and amputation-free survival at 12 months. This study started in NZ in August 2020 and will commence in Australian sites in early 2021.

New Zealand Central Health and Disability Ethics Committee (20/CEN/122), Waikato DHB Research Department (RDO020044), Quality Improvement HoD Sir Charles Gairdner Hospital (39715) and the Central Adelaide Local Health Network (CALHN) Human Research Ethics Committee (13928). Results will be presented at international conferences and published in peer-reviewed journals.

Australian New Zealand Clinical Trials Registry (ACTRN12621000337875).