Competing interests: We have read and understood the BMJ Group policy on declaration of interests and declare the following interests: KH is medical director of the Welsh Wound Innovation Centre (WWIC). This is a company limited by guarantee, and its members include HEIs and NHS units of management in Wales. WWIC is involved in conducting evaluative studies for various treatments for wounds, including dressings, some of which are industry sponsored. This did not influence the views expressed in this article.