Key points from the evidence

The content of this evidence summary was up-to-date in March 2016. See summaries of product characteristics (SPCs), British national formulary (BNF) or the MHRA or NICE websites for up-to-date information.

Overall summary

This evidence summary discusses the best available evidence for advanced wound dressings and antimicrobial dressings for managing common chronic wounds (diabetic foot ulcers, pressure ulcers, venous leg ulcers and infected wounds). It includes evidence and recommendations from national guidance (if available) and the most up‑to‑date systematic reviews and meta‑analyses (search date July 2015).

Dressings should provide the optimal environment for wound healing. For the purposes of this briefing, advanced dressings are those that do this by simple physical or chemical means, typically by controlling moisture levels (for example, alginate, film, foam, hydrocolloid and hydrogel dressings).

Systematic reviews and meta‑analyses have identified little good quality evidence from randomised controlled trials (RCTs) to support the use of advanced or antimicrobial dressings (such as iodine, honey or silver dressings) for chronic wounds. As well as being few in number, many of the RCTs have significant limitations and the evidence is generally of low quality (see evidence strength and limitations for details). Overall, estimates of the effects of dressings are uncertain and not optimal in terms of informing clinical practice. Further good quality research is needed to improve confidence in the evidence, and would probably change the implications for practice.

The systematic reviews and meta‑analyses included in this evidence summary found some low and very low‑quality evidence that some advanced dressings (for example, hydrocolloid, hydrogel, film and foam dressings) are more effective than simple conventional dressings (such as basic wound contact or gauze dressings) for treating some wounds. However, many of the conventional dressings used as comparators are no longer routinely recommended for chronic wounds (for example, gauze dressings) and there is generally insufficient evidence to distinguish between different types of advanced dressings. Studies are also lacking on the cost effectiveness of advanced dressings for managing chronic wounds.

Dressing selection should be made after careful clinical assessment of the person's wound, their clinical condition, and their personal experience and preferences. If a specific dressing cannot be adequately justified on clinical grounds, it would seem appropriate for NHS healthcare professionals to routinely choose the least costly dressing of the type that meets the required characteristics appropriate for the type of wound and its stage of healing (for example, size, adhesion, conformability and fluid handling properties). The frequency of dressing change needs to be carefully considered and should be appropriate for the wound and dressing type. Prescribing the minimum quantity of dressings necessary to meet a person's needs can avoid wastage and stockpiling. Silver dressings should be used only when there are clinical signs or symptoms of infection.

Introduction and current guidance

Over the past 20 years, studies have generated much evidence to show that a moist wound environment is essential for wound healing. This has caused a proliferation of wound dressings with a higher acquisition cost than standard dressings and has left wound care providers confused about when it is appropriate to use these more expensive dressings (Agency for Healthcare Research and Quality 2014).

Advanced wound dressings (for example, alginate, film, foam, hydrocolloid and hydrogel dressings) regulate the wound surface by retaining moisture or absorbing exudate, so protecting the wound base and tissue surrounding the wound. Maintaining a good moisture balance minimises patient discomfort before, during and after dressing changes. Some dressings are used for their antimicrobial properties (for example, iodine, honey and silver dressings). Choice of dressing may change as the nature of the wound base and wound exudate changes. Therefore, the selection of dressings requires training and expertise in wound care (Agency for Healthcare Research and Quality 2014).

The advanced wound dressings section of the BNF provides information on the types and properties of different advanced dressings, and a table that suggests choices of primary dressing depending on the nature of the wound. Factors that should be considered when choosing a dressing include:

  • the stage of wound healing

  • amount of exudate

  • infection

  • odour

  • the adhesiveness of a dressing (ease of removal)

  • irritation caused by the adhesive

  • absorption

  • the frequency of dressing changes

  • ease of use of the dressing

  • amount of pain at dressing changes

  • protection of the surrounding skin

  • patient preference.

In primary care in England, prescription costs of advanced wound dressings and antimicrobial dressings are over £110 million each year, and other procurement routes add to the total NHS expenditure on these products. The wide range of wound dressings and their associated costs present a challenge for healthcare professionals who are managing wounds. Choice requires knowledge of the safety and clinical and cost effectiveness of a wide range of dressings. However, the clinical evidence supporting the use of wound dressings is less well known and of poorer quality than in many other areas of prescribing.

NICE has issued guidance on preventing and managing pressure ulcers and preventing and managing diabetic foot problems. The Scottish Intercollegiate Guidelines Network (SIGN, accredited by NICE) has issued guidance on the management of chronic venous leg ulcers. Although these guidelines give important recommendations about wound care, they do not make recommendations on specific products. Other chronic wounds considered in this evidence summary are arterial leg ulcers and infected wounds.

Full text of introduction and current guidance.

Evidence review

In most of the systematic reviews and meta‑analyses outlined in this evidence summary, the quality of the evidence is rated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system:

  • high quality: further research is very unlikely to change our confidence in the estimate of effect

  • moderate quality: further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate

  • low quality: further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate

  • very low quality: any estimate of effect is very uncertain.

If atypical methods of assessing quality have been used, this has been noted in the discussions.

Diabetic foot ulcers

  • The 2015 NICE guideline on preventing and managing diabetic foot problems found that evidence surrounding different types of dressings for diabetic foot ulcers was generally of low or very low quality and often limited or inconclusive. The guideline recommends wound dressings (type not specified) as an option for managing diabetic foot ulcers, alongside a range of other options provided by a multidisciplinary team. When deciding about wound dressings and other options, the clinical assessment of the wound and the person's preference should be taken into account, and dressings with the lowest acquisition cost appropriate to the clinical circumstances should be used.

  • A Cochrane overview (Wu et al. 2015; 17 randomised controlled trials [RCTs], total number of participants unclear) also concluded that there is currently no robust evidence that any advanced dressing type is more effective than basic wound contact dressings for healing foot ulcers in people with diabetes. Few RCTs were available for each comparison and they generally had small numbers of participants. When direct evidence of a difference was reported, the evidence was considered to be low or very low quality. Therefore, the findings are reported to be uncertain and not optimal in terms of informing practice. The authors concluded that practitioners may want to consider the unit cost of dressings, their management properties and the person's preference when choosing dressings.

  • See the full evidence review on diabetic foot ulcers for more information.

Pressure ulcers

  • The NICE guideline on preventing and managing pressure ulcers found that, overall, the quality of clinical evidence for wound dressings was low to very low because most of the studies had very serious limitations. No recommendations could be made about using specific types of dressings, except that gauze dressings should not be used for pressure ulcers. The NICE guideline development group emphasised that the effectiveness of each dressing would depend on the type of pressure ulcer and, therefore, chose to recommend a dressing that promotes the optimum healing environment, rather than a specific type of dressing. NICE advises that clinicians should discuss the type of dressing with the person with the pressure ulcer and, if appropriate, their family or carers, taking into account the person's pain and tolerance, the position of the ulcer, the amount of exudate and the frequency of dressing change. A dressing that promotes a warm, moist wound healing environment should be considered for grade 2, 3 and 4 pressure ulcers.

  • Two Cochrane reviews on advanced wound dressings for treating pressure ulcers have been published. The first review (Dumville et al. 2015a) (11 RCTs, n=523) found there was no evidence of a difference between hydrogel and other dressings in terms of complete wound healing or adverse events (low‑ or very low‑quality evidence). The second review (Dumville et al. 2015b) (6 RCTs, n=336) found no evidence of a difference between alginate dressings and alternative treatments in complete wound healing (very low‑quality evidence). The RCTs included in both Cochrane reviews were small and considered to be statistically underpowered to detect treatment differences, should they exist. Also, they had short follow‑up times (3 to 12 weeks) and were at risk of bias. The implications for practice are therefore unclear. The authors noted that healthcare professionals may wish to consider other characteristics such as costs and wound management properties when choosing between dressings.

  • A meta‑analysis by Huang et al. (2015) (35 RCTs or quasi‑RCTs, n=5,401) on dressings for preventing pressure ulcers found that compared with standard care alone, the risk of developing pressure ulcers was reduced in people who used hydrocolloid dressings, foam and film dressings. Fewer people in the foam dressings group developed pressure ulcers compared with the hydrocolloid dressings group. However, although the authors stated that the methodological quality of the included studies was assessed using the Cochrane Collaboration tool and the risk of bias is reported, the quality of the evidence is not graded. They noted that the included trials have many limitations and stressed that dressings do not replace best practices, such as turning and repositioning, skin care, good nutrition and continence management. In people who are at risk of pressure ulcers, NICE guidance on preventing and managing pressure ulcers recommends repositioning, ensuring nutrition and hydration are adequate, using pressure redistribution devices and considering barrier creams for preventing pressure ulcers.

  • See the full evidence review on pressure ulcers for more information.

Venous leg ulcers

  • SIGN guidance on the management of chronic venous leg ulcers (published in 2010; accredited by NICE) advises that simple non‑adherent dressings and high compression multicomponent bandaging should be used for treating venous leg ulcers. Silver and honey dressings should not be used routinely. Graduated compression hosiery is recommended to prevent recurrence of venous leg ulcers. The evidence that the SIGN recommendations were based on is updated by the evidence outlined below.

  • Three Cochrane reviews have considered wound dressings for healing venous leg ulcers. The first review (O'Meara et al. 2015) (5 RCTs, n=295) found no differences between different alginate dressings, or between alginate dressings and hydrocolloid dressings, or alginate dressings and non‑adherent dressings. The second review (O'Meara and Martyn-St James 2013) (12 RCTs, n=1,023) found no differences between foam dressings and a variety of other primary wound contact dressings when applied beneath compression systems. The RCTs included in these 2 Cochrane reviews were considered at high or unclear risk of bias and the quality of the evidence was generally reported to be low or very low quality. The authors concluded that good‑quality evidence from well‑designed RCTs is needed before definitive conclusions about the efficacy of alginate or foam dressings for managing venous leg ulcers can be drawn and recommendations about their use can be made.

  • No trials were identified comparing different dressings for relieving pain in venous leg ulceration in the third Cochrane review (Briggs et al. 2012). Foam dressings containing ibuprofen (2 RCTs, n=470) did appear to provide pain relief for some people with painful venous leg ulcers compared with best practice or non‑medicated foam dressings. However, the authors of the Cochrane review noted that the studies have methodological limitations that make interpreting the evidence difficult. Also, the release of ibuprofen into the wound bed depends on the presence of wound exudate and therefore these dressings are not suitable for people with venous leg ulcers that have low levels of, or no, exudate.

  • The Agency for Healthcare Research and Quality (2014) (AHRQ) in the USA considered the benefits and harms of dressings that regulate wound moisture in people with chronic venous leg ulcers. In terms of the proportion of ulcers healed, no differences were found between the groups for comparisons including advanced wound dressings (film, alginate and antimicrobial dressings, including silver dressings). Definitive conclusions could not be drawn for many comparisons because of limitations in study quality, imprecise estimates and heterogeneity in study designs. Also, conclusions about the effects of advanced wound dressings on pain or quality of life could not be made due to inconsistent reporting of these outcomes. The AHRQ stated that there was a general lack of well‑designed, well‑controlled studies, as well as lack of a standard case definition, or approaches to managing confounders and interactions. For advanced wound dressings, there was no impact on wound healing when compared with compression therapy alone.

  • A meta‑analysis of 2 RCTs (n=255) of silver dressings for venous leg ulcers by Greer et al. (2013), which were assessed as fair quality by the authors, found that there was no difference between silver dressings and non‑silver dressings. A second study by Leaper et al. (2013) (4 RCTs, n=1,055) found that, compared with control (foam or alginate dressings, or local best practice including passive and non‑antimicrobial dressings), a specific brand of silver dressings reduced ulcer area over 4 weeks in people with hard‑to‑heal venous leg ulcers.However, this meta‑analysis has many limitations that affect its interpretation. For example, it did not report the quality of the evidence or assess the risk of bias, complete data were not reported for all outcomes, only 1 brand of silver dressing was assessed and, as well as sponsoring the study, the manufacturer of that brand of dressing was involved in authoring the paper.

  • Economic modelling of data from 1 of the RCTs in the meta‑analyses (the VULCAN trial [Michaels et al. 2009], n=213) found that silver dressings were associated with an incremental cost of £97.85 compared with control dressings when used for treating venous leg ulcers. The additional cost of silver dressings was partly due to an increased cost of dressings, but also due to a greater number of dressing changes in the silver dressings group. Although it was a pragmatic, publicly funded, well‑designed RCT that reflected standard practice at the time it was undertaken, this study (and its cost‑effectiveness analysis) has been criticised for its relevance and generalisation to everyday clinical care; for example, participants did not necessarily have wounds that were infected or were at high risk of becoming infected (Gottrup and Apelqvist 2010).

  • A more recent study by Jemec et al. (2014) used data from the meta‑analysis by Leaper et al. (2013) and estimated that the initial 4 weeks' treatment in primary care was about £90 more expensive for the group treated with silver dressings compared with non‑silver dressings. However, because of a shorter time to wound healing and less need for referral for specialist care, the average total treatment cost per person was about £140 lower for silver dressings compared with non‑silver dressings. It is unclear how the outcome time to wound healing was obtained from the outcomes presented by Leaper et al. (2013) (primarily reduced ulcer area). Also, the limitations of the study by Leaper et al. (2013) subsequently limit the quality of the cost‑effectiveness analysis and affect its application to practice.

  • See the full evidence review on venous leg ulcers for more information.

Arterial leg ulcers

Infected wounds

  • A meta‑analysis by Carter et al. (2010) (10 RCTs, n=1,356) found no difference between silver dressings and control dressings in complete healing of leg wounds and ulcers, although reduction in wound size was greater with silver dressings in the short term. Measures of infection were not assessed. Although they noted that all of the RCTs on silver dressings had quality or bias issues, none were considered by the authors to be poor quality. However, this study assessed the quality of the evidence using an atypical approach. Also, the included RCTs had many limitations, including lack of blinding or allocation concealment, use of inappropriate analyses, incomplete reporting, lack of generalisability to real world populations, differences in baseline characteristics and loss of patients to follow‑up.

  • A Cochrane review (Storm-Versloot et al. 2010) on topical silver products (dressings or creams) for preventing wound infection identified 26 RCTs (n=2,066), 20 of which considered burns. Most of the trials were small and of poor quality, with many demonstrating a high or uncertain risk of bias. The authors considered that there was insufficient evidence to support the use of silver dressings or creams because, generally, they did not promote wound healing or prevent wound infections.

  • A Cochrane review by Jull et al. (2015) concluded that honey appeared to heal partial thickness burns (2 RCTs, n=992: high‑quality evidence) and infected post‑operative wounds (1 RCT, n=50: moderate‑quality evidence) more quickly than comparators. However, the comparators used may not be relevant to current practice (for example, paraffin gauze, sterile linen and gauze), reducing the relevance and generalisability of the results. Evidence for differences in the effects of honey and comparators when used for other wounds is of low or very low quality and does not form a robust basis for decision‑making.

  • A systematic review (Vermeulen et al. 2010) (27 RCTs, number of participants not reported) found that most RCTs showed no substantial differences in beneficial or adverse effects between iodine (mainly povidone or cadexomer iodine) and comparators when used for chronic and acute wounds, burn wounds, pressure sores and skin grafts. Overall, trial quality was limited. The authors concluded that iodine does not appear to be inferior to other antiseptic agents and does not impair wound healing. However, there is a need for high‑quality RCTs addressing the effectiveness and safety of iodine to treat or prevent wound infection, in order to clearly determine its place in present‑day wound care.

  • See the full evidence review on infected wounds for more information.

Evidence strengths and limitations

  • Dressings are generally classified as medical devices. The quality of the evidence required for approval of medical devices is generally lower than that required for medicines. This is reflected in the poor quality of many of the RCTs in this area.

  • Few RCTs were available for many of the comparisons considered in the systematic reviews and meta‑analyses. Limitations of the RCTs include poor design and reporting, high risk of bias, small sample sizes and imprecision, lack of blinding, use of inappropriate comparators, lack of clinically relevant outcomes and insufficient follow‑up.

  • The limitations of the RCTs, and subsequently the systematic reviews and meta‑analyses based on those RCTs, means that good‑quality evidence is available for few analyses of advanced wound dressings for managing chronic wounds. Overall, the clinical evidence is generally uncertain and not optimal in terms of informing clinical practice. Further good quality research is needed to improve confidence in the evidence, and is likely to change the existing evidence. Studies are also lacking on the cost effectiveness of advanced dressings for managing chronic wounds.

  • See the full evidence review on evidence strengths and limitations for more information.

Full text of evidence review.

Context

Although representing only 1 route by which dressings are procured within the NHS, the prescription costs of advanced wound dressings and antimicrobial dressings in primary care in England were over £110 million in the year to August 2015 (based on British National Formulary [BNF] volume 69 sections at presentation level; personal communication: NHS Business Services Authority 2015). There is considerable variation in the cost of dressings both between categories of dressings and within each category. For example, silver dressings accounted for about 9% of items supplied on prescription, but in view of their relatively high cost were associated with over 18% (£20.5 million) of the total cost of advanced wound dressings.

Full text of context.

Estimated impact for the NHS

A large number of wound dressings are available with a wide range of physical performance characteristics (such as size, adhesion, conformability and fluid‑handling properties). Although laboratory characterisation tests provide a means of comparing the performance characteristics of dressings, they cannot always predict how they will perform in the clinical situation, particularly in terms of healing.

Prescribers' ability to choose wound dressings on the basis of clinical evidence is hindered by the relative lack of robust clinical‑ or cost‑effectiveness evidence, as highlighted in numerous systematic reviews. There is some limited evidence that some advanced dressings are more clinically effective than simple conventional dressings for treating some wounds. For example, systematic reviews and meta‑analyses found:

  • hydrogel dressings were more effective than basic wound contact dressings for complete healing of diabetic foot ulcers (low‑quality evidence), as were foam dressings (very low‑quality evidence)

  • hydrocolloid and polyurethane film dressings were more effective than gauze dressings in terms of the proportion of pressure ulcers completely healed (low‑quality evidence).

However, many of the conventional dressings used as comparators are no longer routinely recommended for chronic wounds (for example, gauze dressings) and there is generally insufficient evidence to distinguish between advanced dressings.

Dressing selection should be made after careful clinical assessment of the person's wound, their clinical condition, and their personal experience and preferences. If 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 meets the required characteristics appropriate for the type of wound and its stage of healing (for example, size, adhesion, conformability and fluid handling properties). The frequency of dressing change needs to be carefully considered and should be appropriate for the wound and dressing type. Patients should be assessed regularly. Prescribing the minimum quantity of dressings necessary to meet a person's needs can avoid wastage and stockpiling.

The silver dressings section of the BNF states that antimicrobial dressings containing silvershould be used only when clinical signs or symptoms of infection are present. Silver ions exert an antimicrobial effect in the presence of wound exudate; therefore, the volume of wound exudate as well as the presence of infection should be considered when selecting a silver dressing. Local protocols may be useful to help clinicians decide when silver dressings should be used.

In view of the multitude of dressings available, the absence of good‑quality evidence for national guidelines to base specific recommendations on, and recognising financial constraints, local formularies provide a means of rationalising choice of dressings. Educational programmes can help to ensure that use of formulary wound dressings is optimised.

Full text of estimated impact for the NHS.

About this evidence summary: medicines and prescribing briefing

'Evidence summaries: medicines and prescribing briefings' aim to review the evidence for the clinical effectiveness of medicines within a therapeutic class or indication to provide advice on the relative position of each medicine as a therapeutic option. This will assist localities in their planning on medicines optimisation priorities as well as providing individual prescribers with information to help informed decision making. The strengths and weaknesses of the relevant evidence are critically reviewed to provide useful information, but this evidence summary: medicines and prescribing briefing is not NICE guidance.