INDUCE study

Point of care tests to assist antibiotic prescribing decisions for diabetic foot ulcer infections.

Background

There are 160,000 people with diabetes in Wales, representing one in twenty of the population, and the lifetime risk of development of diabetic foot ulcers (DFUs) approaches 25%. Direct costs for the care of DFUs are more than £250 million in the UK and indirect costs, including amputation, are much higher. Diagnosis of DFU infection remains entirely clinical and there is no objective test at the point of patient care to assist antibiotic prescribing decisions.

Simple, easy to use and effective test

A cheap, rapid point of care test (POCT) using a pinprick blood sample for C reactive protein (CRP) has been shown to safely halve antibiotic prescriptions for chest infections in primary care. Combination of CRP and another marker, procalcitonin, has been safely used in a pilot study to distinguish between non-infected and mildly infected DFUs. This study of 45 patients required laboratory analysis of samples and so results were not available to guide clinicians at the time of ulcer assessment.

Safety considerations

The proposed pilot study of 110 DFU patients will include those with non-infected and mildly infected ulcers. Participant recruitment will be from the 10 DFU podiatry clinics in Cardiff that occur each week. More serious ulcer infections will be excluded to ensure that clinical care is not compromised.

Using technology for patient benefit

An online educational tool will also be developed for clinicians to support decision making during the consultations. The pilot study will compare the POCT results to a gold standard for diagnosis of DFU infection, namely clinical impression at initial assessment and one week later, incorporating the response to any antibiotics prescribed initially. The POCT results will not be used for diagnostic purposes in the pilot study.

Potential implications of results

Results from this pilot study will hopefully lead to the development of at a randomised controlled trial of POCTs and the educational intervention for DFU infections in GP practices and podiatry clinics. The composite POCT could also be applied to other primary care infection settings.

Study design

The population under study, and the recruitment in a community –based setting, the target population and the use of combined biomarker tests, to identify infection and guide better antimicrobial stewardship.

As with all trials, adaptions were required in order for the study to improve recruitment rates. Adjustments in inclusion criteria were made, and the addition of more recruiting sites was required throughout the course of the study.

Involving the public and patients

For INDUCE, a patient representative who has diabetes and has suffered with DFUs in the past, was part of the management team from the outset. Geraldine’s experience was invaluable to the design and delivery of the study.

Funder: Health and Care Research Wales – RffpB Funding (Ref 1018)

Chief Investigator: Dr John Ingram