Authors' objectives: Foot ulcers affecting people with diabetes (diabetic foot ulcers) often become infected, potentially leading to amputation. Suspected diabetic foot ulcer infection is treated with immediate empiric antimicrobials, with wound samples for culture and sensitivity collected to optimise antibiotic therapy. Collecting samples with swabs is easier than obtaining tissue, but this reports fewer pathogens and more contaminants. Compared with standard culture and sensitivity laboratory methods, molecular microbiology identifies more organisms. How these differences affect clinical decisions or outcomes is currently unknown. Objectives Main study To determine if taking tissue samples versus swabs from suspected infected diabetic foot ulcer affects ulcer healing, antibiotic prescribing, costs of care and patient safety.

Authors' results and conclusions: The trial was stopped early, after enrolling only 149 participants, due to poor recruitment. Main study The hazard ratio for wound healing for patients undergoing tissue versus swab sampling was 1.01 (95% confidence interval 0.65 to 1.55). The swab group had both higher quality-adjusted life-years and lower costs across most time points. Trial recruitment was challenging during the COVID pandemic and its aftermath. While the results leave substantial uncertainty regarding differences in healing between the sampling methods, tissue sampling appeared to be costlier and was associated with lower quality-adjusted life-years than swabbing.

Authors' methods: Main study Randomised controlled trial of results of performing tissue sampling versus swabbing of wounds in people with suspected mild or moderate infected diabetic foot ulcer. Individually randomised (allocation concealed), 1 : 1, tissue or swab sampling for suspected diabetic foot ulcer infection. Follow-up is 12–24 months. A priori sample size estimate is 730. Twenty-one United Kingdom diabetic foot ulcer clinics. Participants with suspected mild or moderate infected diabetic foot ulcers. Main outcome measures Main study Time to ulcer healing (primary outcome blinded assessment), proportion of ulcers healed, antibiotic usage, ulcer area reduction at 4 weeks, hospitalisation duration, time to death, quality of life and cost-effectiveness. The trial was underpowered.

Project Status: Completed

URL for project: https://www.journalslibrary.nihr.ac.uk/programmes/hta/NIHR136257

Year Published: 2025

URL for published report: https://www.journalslibrary.nihr.ac.uk/hta/KKPP0404

URL for additional information: English

English language abstract: An English language summary is available

Publication Type: Full HTA

Country: England, United Kingdom

DOI: 10.3310/KKPP0404

Organisation Name: NIHR Health Technology Assessment programme

Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

Contact Name: journals.library@nihr.ac.uk

Contact Email: journals.library@nihr.ac.uk