John: Diabetes affects millions of people worldwide, causing a variety of health problems, including foot ulcers. In a new Cochrane Overview in July 2015, Jo Dumville from the Division of Nursing and Midwifery at the University of Manchester in the UK and colleagues bring together the findings from 13 systematic reviews. She summarises all this evidence in this Evidence Pod.

Jo: Diabetes mellitus (generally known as 'diabetes'), causes a rise in the sugar levels in the blood when untreated. It’s a serious health issue and foot ulcers are a relatively common problem, affecting at least one in seven people with diabetes at some time during their lives. Foot ulcers are open wounds that occur below the ankle: they can be painful and prone to infection and have a serious impact of people’s lives. They can also be a pre-cursor to other serious outcomes such as toe or limb amputation.
Wound dressings are a cornerstone treatment of foot ulcers, and are used extensively. There are several different types of dressings available, from basic dressings such as gauze to more advanced gels, films, and specialist dressings that may be saturated with ingredients that exhibit particular properties (such as silver which is purported to have antimicrobial activity). We’ve brought together the findings of the several Cochrane and non-Cochrane reviews that have explored the effects of these various dressings in this overview. Our key outcomes of interest were wound healing, health-related quality of life, resource use and costs, and other management properties of the dressing.
We drew together and summarised evidence from six Cochrane and seven non-Cochrane reviews, which collectively contained data from 17 relevant randomised trials. We judged the reviews to be of generally high quality.
We also included a network meta-analysis in the overview, and present evidence informed by both direct and indirect data. This allowed us to compare a total of 10 different types of wound dressings against each other. Four of the comparisons informed by direct data found evidence of a difference in ulcer healing between dressings, but this was low or very low quality evidence and difficult to interpret with confidence. The data for other outcomes was very limited.
We conclude that there is currently no robust evidence of differences between wound dressings for any outcome in foot ulcers in people with diabetes (treated in any setting). Therefore, when choosing dressings, practitioners may want to consider the unit cost of dressings, together with their management properties and patient preferences. The doubts about the relative effects of the dressings could be tackled through new research studies, involving larger numbers of participants but such research would be costly. So, it’s important that the value of further research should be considered carefully, along with whether resolving uncertainty in this area is a priority for patients and clinical decision makers.

John: If you would like to find out more about the existing evidence from the more than a dozen reviews in Jo’s overview, you can find it at Cochrane Library dot com with a search 'foot ulcer dressings and diabetes’' where you’ll also be able to link to the full versions of the relevant Cochrane Reviews.