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6 January 2012
Cochrane reviews of foam dressings and hydrogel dressings for healing of diabetic foot ulcers have found insufficient good quality clinical evidence to suggest that either of these types of dressings is more effective than other types of dressings.
Level of evidence:
Level 2 (limited quality patient-oriented evidence) according to the SORT criteria.
Action
Healthcare professionals should follow NICE clinical guideline 119 for the management of diabetic foot ulcers. When choosing wound dressings, healthcare professionals from the multidisciplinary foot care team should take into account their clinical assessment of the wound, patient preference and the clinical circumstances and choose wound dressings (appropriate to the type of wound and stage of healing) with the lowest acquisition cost.
What is the background to this?
Choice of the most appropriate dressing for a chronic wound, such as a diabetic foot ulcer, requires careful clinical assessment and depends not only on the type of wound but also on the stage of healing, and different dressings may be required throughout the healing process. For example: hydrogel dressings may be used to keep the wound moist, whereas foam dressings may be used to absorb wound exudates. Among each of the categories of dressing, there is a wide choice of products available, with different physical characteristics and costs. A MeReC Bulletin (July 2010) found that there was insufficient high-quality evidence to distinguish between any of the advanced wound dressings used in the management of chronic wounds, including diabetic foot ulcers. These two systematic reviews of randomised controlled trials (RCT), using research data published up to June 2011, assessed the effects of foam dressings and hydrogels on the healing of diabetic ulcers in comparison with alternative dressings, or in the case of hydrogels, some alternative treatments.
What do the studies claim?
The systematic review of foam dressings (six studies, n=157) found that there was no evidence to suggest that foam wound dressings were more effective in healing diabetic foot ulcers than other types of dressings.
The systematic review of hydrogel dressings (5 studies, n=466) found that there was some evidence that hydrogel dressings were more effective in healing (lower grade) diabetic foot ulcers than basic wound contact layers, however this finding was uncertain due to risk of bias in the original studies. No RCTs were identified comparing hydrogel dressings with other advanced dressings.
So what?
These Cochrane reviews indicate the lack of good quality RCT evidence to support the use of any particular hydrogel or foam dressings for the management of diabetic foot ulcers. This is also the case for silver dressings; another Cochrane review, earlier in 2011, concluded that “despite the widespread use of dressings and topical agents containing silver for the treatment of diabetic foot ulcers, no randomised trials or controlled clinical trials exist that evaluate their clinical effectiveness.” These findings are consistent with other reviews of wound dressings for the treatment of chronic wounds generally (see MeReC Bulletin).
Recognising that clinical practice should be evidence based, the European Wound Management Association (EWMA) patient outcome group issued recommendations in 2010 to improve the quality of evidence in the management of difficult-to-heal wounds such as diabetic ulcers. However, at this point in time, in the absence of any good evidence to distinguish between dressings on efficacy or safety grounds, dressing choice needs to be based on other factors including patient preference, tolerance and costs. Where a specific dressing cannot be adequately justified on clinical grounds, it would seem appropriate for NHS health professionals to routinely choose the least costly dressing of the type that has the required characteristics (e.g. size, adhesion, conformability, fluid handling properties, etc.) appropriate for the type of wound and its stage of healing, taking into account patient preferences.
There may be opportunity for considerable cost savings by reviewing the dressings that are routinely being used for chronic wound treatment. In the year up to September 2009 the cost of advanced wound dressings in primary care in England alone was approximately £116 million pounds, of which foam dressings and silver dressings each accounted for about 20% of the total cost (hydrogels accounted for about 2%).
Design:
Systematic review and meta-analysis of RCTs that evaluated wound healing.
Patients:
Patients with diabetic foot ulcers.
Intervention and comparison:
RCTs were included in which the presence or absence of a foam dressing was the only systematic difference between treatment groups.
Outcomes and results
Six studies (157 participants) were included in the review. Meta-analysis of two studies indicated that foam dressings do not promote the healing of diabetic foot ulcers compared with basic wound contact dressings (risk ratio [RR] 2.03, 95% confidence interval [CI] 0.91 to 4.55). Pooled data from two studies comparing foam and alginate dressings found no statistically significant difference in ulcer healing (RR 1.50, 95% CI 0.92 to 2.44). There was no statistically significant difference in the number of diabetic foot ulcers healed when foam dressings were compared with hydrocolloid (matrix) dressings. All included studies were small and/or had limited follow-up times.
Design:
Systematic review and meta-analysis of RCTs that evaluated wound healing.
Patients:
Patients with diabetic foot ulcers.
Intervention and comparison:
RCTs were included in which the presence or absence of a hydrogel dressing was the only systematic difference between treatment groups.
Outcomes and results
Five studies (n=446) were included in this review. Meta-analysis of three studies comparing hydrogel dressings with basic wound contract dressings found significantly greater healing with hydrogel: RR 1.80, 95% CI 1.27 to 2.56. The three pooled studies had different follow-up times (12 weeks, 16 weeks and 20 weeks) and also evaluated ulcers of different severities (grade 3 and 4; grade 2 and grade unspecified). One study compared a hydrogel dressing with larval therapy and found no statistically significant difference in the number of ulcers healed and another found no statistically significant difference in healing between hydrogel and platelet-derived growth factor. There was also no statistically significant difference in number of healed ulcers between two different brands of hydrogel dressing. All included studies were small and at unclear risk of bias and there was some clinical heterogeneity with studies including different ulcer grades. No included studies compared hydrogel with other advanced wound dressings.
Sponsorship: Cochrane Reviews are not funded by commercial organisations.
Further information can be found on NHS Evidence and in the wound care e-learning materials on the NPC website.
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