CODIFI2
Research type
Research Study
Full title
CODIFI2: Randomised controlled trial of swab versus tissue sampling for infected diabetic foot ulcers, and comparison of culture versus molecular processing techniques
IRAS ID
253191
Contact name
Andrea Nelson
Contact email
Sponsor organisation
University of Leeds
ISRCTN Number
74929588
Clinicaltrials.gov Identifier
N/A, N/A
Duration of Study in the UK
4 years, 3 months, days
Research summary
Research Summary
When infection is suspected in a diabetic foot ulcer, the clinician will collect a specimen from the wound to send to a laboratory to identify the bacteria causing the infection. There are two ways to collect a wound sample: collecting wound fluid using a cotton swab (wound swab), or taking a small piece of wound tissue (tissue sample).
Swabs are easier and is the most common method used, however some experts and guidelines recommend tissue sampling as it is better at collecting harmful bacteria. We want to test whether the information from tissue samples helps clinicians better match the antibiotics to the infection, and so cure the infection and help the ulcer heal more quickly.To make a fair comparison of swab versus tissue sampling we will recruit 730 people with diabetic foot ulcer infection. In this trial, we will randomly allocate the way the sample is taken; either a swab or tissue sample. The clinical team will decide on all aspects of each patient’s care, such as dressings, off-loading and medications.
We will follow these patients and collect information on their treatment, ulcer size and infection (until the ulcer heals or 1-2 years later), their overall health, and treatments and care they have had for their foot ulcer, using hospital notes and a postal questionnaires. For the postal questionnaires we will also study the impact differing covering letters have on return rates to help improve these in future studies.During the first sampling session we will also take a 2nd wound sample to test for bacterial DNA. We will use this data to tell us whether these tests find more bacteria than growing them in the laboratory, and if so, would this potentially change antibiotic treatment and to see if this information can improve predicted ulcer healing times.
Summary of Results
We recruited 149 participants (75 randomised to swab, 74 to tissue sampling) from 21 UK sites, between 7 May 2019 and 28th April 2022 (last follow-up 28th April 2023). The trial closed to recruitment early due to recruitment issues, which substantially affected sample sizes and data collection. The planned sample size was 730 participants. There was no evidence of difference between the two sampling approaches when considering time to healing up to 52 or 104 weeks (the main outcome) but there is a lot of uncertainty around this result because fewer people were recruited to the study than we had planned. Whilst there was no evidence of difference for time to healing, quality of life was higher for patients who had a swab sample taken at weeks 26, 52 and 104 compared to those who had a tissue sample taken. In addition, the cost of taking a tissue sample was greater than the cost of taking a swab when we also included antibiotics, being admitted to hospital and other costs of wound care.
Overall, therefore, we concluded that taking a swab sample was more cost effective, however there is a high level of uncertainty due to the low number of patients recruited.REC name
West of Scotland REC 3
REC reference
18/WS/0235
Date of REC Opinion
19 Dec 2018
REC opinion
Favourable Opinion