Negative Pressure Wound Therapy versus usual care in patients with surgical wounds healing by secondary intention (SWHSI-2):an open, UK, multi-centre, parallel randomised clinical trial

Background: Surgical wounds healing by secondary intention (SWHSI) present a significant management and financial challenge. Negative pressure wound therapy (NPWT) has increasingly been used as a treatment despite limited comparative evidence of effectiveness. We evaluated the effectiveness of NPWT compared with usual care for improving time to wound healing in patients with a SWHSI. Methods: A pragmatic, parallel group, multicentre, two-arm randomised controlled trial in 29 UK NHS Trusts. Participants aged 16 years or older with a SWHSI appropriate for both study treatments (NPWT or usual care) were randomly assigned (1:1) by a centralised web-based system. Randomisation was stratified by wound location, wound area, and study centre. Participants were followed up for 12 months. Participants, clinical and research teams could not be blinded. Blinded assessors reviewed wound photography to verify the outcome. The primary outcome was time to wound healing (days from randomisation to complete epithelial cover), analysed via intention to treat using Kaplan Meier survival curves and a proportional hazards Cox regression model. The trial was pre-registered with ISRCTN (ISRCTN26277546). Findings: Between 15th May 2019 and 13th January 2023, 686 participants with a SWHSI were randomised to receive NPWT (n=349) or usual care (n=337). All participants were included in the primary analysis. Most participants were diabetic (n=549, 80.0%) and had a single SWHSI (n=622, 90·7%), located on the foot or leg (n=620, 90.4%), arising following vascular surgery (n=619, 90·2%).There was no clear evidence that NPWT reduced the time to wound healing compared to usual care (HR 1·08, 95%CI 0·88 to 1·32, p=0.47). Across the study, there were 448 adverse events of which 14 were serious; 124 were deemed potentially related to treatment. NPWT was found not to be cost-effective compared to usual care. Interpretation: In patients with a lower limb SWHSI, including those with complications of diabetes, there is no clear evidence that NPWT reduced the time to wound healing compared with standard dressings. These findings do not support the use of NPWT to augment SWHSI healing. Funding: National Institute for Health Research (NIHR) Health Technology Assessment Programme (Project Reference: 17/42/94).