Woundchek Protease Status for assessing elevated protease status in chronic wounds

Published evidence

Four publications on the Woundchek Protease Status test to assess chronic wounds are summarised in this briefing. The studies included 1 prospective, non-comparative study (Izzo et al. 2014); 1 poster presentation (Gibson et al. 2013), which included the results of 2 prospective non-comparative studies; 1 oral presentation (Duteille et al. 2013) on a prospective, non-comparative study and 1 oral presentation on a non-blinded randomised controlled trial (Anichini et al. 2013). There were a total of 412 patients in the 4 included studies.

The prospective, non-comparative study by Izzo et al. (2014) screened for elevated protease activity (EPA), with the Woundchek Protease Status test, in 35 patients who needed a dermal graft for their diabetic foot ulcers. Duteille et al. (2013) gave the results from a prospective, non-comparative study of 30 chronic wounds in an oral presentation. Chronic wounds were assessed for EPA using the Woundchek Protease Status test before a dermal graft was done.

Gibson et al. (2013) presented the results from 2 studies in a poster. Both studies were prospective and non-comparative. The first study (Study A) investigated the prevalence of EPA in a range of chronic wounds as well as the duration of wounds with EPA and disagreements between clinician opinion and wound area reduction. The second study (Study B) aimed to determine how frequently clinicians would choose to use the Woundchek Protease Status test to assess a chronic wound. If the clinician chose not to use the Woundchek Protease Status test, they noted their reasons for this decision.

The oral presentation by Anichini et al. (2013) gave the results from a non-blinded randomised controlled trial of 20 diabetic foot ulcers. Patients (n=20) were randomised to either have testing for EPA with the Woundchek Protease Status test (n=10) or standard care (n=10). Table 3 summarises the clinical evidence as well as its strengths and limitations.

Strengths and limitations of the evidence

Overall there was limited evidence on using the Woundchek Protease Status test for chronic wounds and only 1 study used the test to determine the choice of dressing. Two studies (Izzo et al. 2014 and Duteille et al. 2013) assessed whether the test could predict graft failure and this may not be generalisable to non-healing wound prediction.

The paper by Izzo et al. (2014) was a full text journal article and therefore included more detailed reporting of the study than the poster presentation by Gibson et al. (2013) and the oral presentations by Duteille et al. (2013) and Anichini et al. (2013). The studies by Izzo et al. (2014) and Anichini et al. (2013) received no funding from Woundchek and no employees were involved with the studies. The study by Duteille et al. (2013) was supported by a grant from Systagenix, owned by Acelity, who also own Woundchek. Six out of seven named authors on the poster by Gibson et al. (2013) work for Woundchek or Systagenix.

The study by Anichini et al. (2013) compared the use of the Woundchek Protease Status test with standard care in a prospective, randomised manner. It is unclear if allocation concealment was done and the study was not blinded. Therefore, selection bias, performance bias and detection bias may have been introduced. The remaining studies were non-comparative.

The studies had variable levels of reporting on the statistical techniques used to analyse results. The study by Izzo et al. (2014) used the Woundchek Protease Status test in patients with chronic wounds having a dermal graft, and analysed the data using inferential statistics. The study by Anichini et al. (2013) included p values but the methods of statistical analysis were not presented. Gibson et al. (2013) also did some statistical analysis (positive-predictive value), whereas Duteille et al. (2013) analysed graft success rates but did not include confidence intervals or ranges.

The studies by Izzo et al. (2014), Duteille et al. (2013) and Anichini et al. (2013) had relatively small sample sizes of between 20 and 35 people compared with Gibson et al. (2013) which included 215 people. The studies by Izzo et al. (2014) and Anichini et al. (2013) presented some inclusion criteria but no exclusion criteria. Neither Gibson et al. (2013) or Duteille et al. (2013) presented inclusion or exclusion criteria.

The studies by Izzo et al. (2014), Anichini et al. (2013) and Duteille et al. (2013) were single-centre studies, which may decrease selection bias. But they did not report whether patients were recruited consecutively or not. The 2 studies presented by Gibson et al. (2013) were multi-centre. This could mean that each centre had a low number of patients, and each centre would have had different clinicians, treatments and assessment procedures. Conversely, multi-centre studies evaluate the use of the technology in different centres increasing the generalisability of the results. The studies by Izzo et al. (2014), Anichini et al. (2013) and Duteille et al. (2013), as well as 1 of the studies presented by Gibson et al. (2013), were done outside of the UK and therefore treatment and assessment procedures may differ from UK standard care. One of the studies presented by Gibson et al. (2013) was done in the UK and so its results may be more generalisable to the NHS. However this study presented results on clinical decision making and not patient outcomes.

Recent and ongoing studies

Two trials on this technology were identified:

The manufacturer provided the following information on these studies: NCT01537003 and NCT01537016 started but were cancelled when the technology was divested in 2013, following acquisition of Systagenix by Acelity (formerly KCI). Woundchek is currently auditing the data collected up to the point of termination, with the intention to analyse and publish the results.