Dressings and topical agents for treating venous leg ulcers

BACKGROUND

Venous leg ulcers are open skin wounds on the lower leg which can be slow to heal, and are both painful and costly. The point prevalence of open venous leg ulcers in the UK is about 3 cases per 10,000 people, and many people experience recurrent episodes of prolonged ulceration. First-line treatment for venous leg ulcers is compression therapy, but a wide range of dressings and topical treatments are also used. This diversity of treatments makes evidence-based decision-making challenging, and a clear and current overview of all the evidence is required. This review is a network meta-analysis (NMA) which assesses the probability of complete ulcer healing associated with alternative dressings and topical agents.

OBJECTIVES

To assess the effects of (1) dressings and (2) topical agents for healing venous leg ulcers in any care setting and to rank treatments in order of effectiveness, with assessment of uncertainty and evidence quality.

SEARCH METHODS

In March 2017 we searched the Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid Embase and EBSCO CINAHL Plus. We also scanned reference lists of relevant included studies as well as reviews, meta-analyses, guidelines and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting. We updated this search in March 2018; as a result several studies are awaiting classification.

SELECTION CRITERIA

We included published or unpublished randomised controlled trials (RCTs) that enrolled adults with venous leg ulcers and compared the effects of at least one of the following interventions with any other intervention in the treatment of venous leg ulcers: any dressing, or any topical agent applied directly to an open venous leg ulcer and left in situ. We excluded from this review dressings attached to external devices such as negative pressure wound therapies, skin grafts, growth factors and other biological agents, larval therapy and treatments such as laser, heat or ultrasound. Studies were required to report complete wound healing to be eligible.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, 'Risk of bias' assessment and data extraction. We conducted this NMA using frequentist meta-regression methods for the efficacy outcome; the probability of complete healing. We assumed that treatment effects were similar within dressings classes (e.g. hydrocolloid, foam). We present estimates of effect with their 95% confidence intervals (CIs) for individual treatments focusing on comparisons with widely used dressing classes, and we report ranking probabilities for each intervention (probability of being the best, second best, etc treatment). We assessed the certainty (quality) of the body of evidence using GRADE for each network comparison and for the network as whole.

MAIN RESULTS

We included 78 RCTs (7014 participants) in this review. Of these, 59 studies (5156 participants, 25 different interventions) were included in the NMA; resulting in 40 direct contrasts which informed 300 mixed-treatment contrasts.The evidence for the network as a whole was of low certainty. This judgement was based on the sparsity of the network leading to imprecision and the general high risk of bias in the included studies. Sensitivity analyses also demonstrated instability in key aspects of the network and results are reported for the extended sensitivity analysis. Evidence for individual contrasts was mainly judged to be low or very low certainty.The uncertainty was perpetuated when the results were considered by ranking the treatments in terms of the probability that they were the most effective for ulcer healing, with many treatments having similar, low, probabilities of being the best treatment. The two most highly-ranked treatments both had more than 50% probability of being the best (sucralfate and silver dressings). However, the data for sucralfate was from one small study, which means that this finding should be interpreted with caution. When exploring the data for silver and sucralfate compared with widely-used dressing classes, there was some evidence that silver dressings may increase the probability of venous leg ulcer healing, compared with nonadherent dressings: RR 2.43, 95% CI 1.58 to 3.74 (moderate-certainty evidence in the context of a low-certainty network). For all other combinations of these five interventions it was unclear whether the intervention increased the probability of healing; in each case this was low- or very low-certainty evidence as a consequence of one or more of imprecision, risk of bias and inconsistency.

AUTHORS' CONCLUSIONS

More research is needed to determine whether particular dressings or topical agents improve the probability of healing of venous leg ulcers. However, the NMA is uninformative regarding which interventions might best be included in a large trial, largely because of the low certainty of the whole network and of individual comparisons.The results of this NMA focus exclusively on complete healing; whilst this is of key importance to people living with venous leg ulcers, clinicians may wish to take into account other patient-important outcomes and factors such as patient preference and cost.

Combined Topical Growth Factor and Protease Inhibitor in Chronic Wound Healing: Protocol for a Randomized Controlled Proof-of-Concept Study

Background

Leg ulcers due to venous disease are chronic wounds that can take 6 or more months to heal. Growth factors have been used to try and improve this healing; however, many such studies have failed, and that is thought to be due to enzymes in the wound that degrade the growth factors and prevent them from working.

Objective

This is a proof-of-concept study that will evaluate the treatment of chronic leg ulcers with topically applied growth factors that are combined with a therapy to prevent their inactivation in the wound. This combined therapy has the potential to speed up the healing of these wounds and thereby improve the quality of life of patients and reduce the costs to the health system.

Methods

This will be a double-blind, placebo-controlled, randomized controlled proof-of-concept study comparing growth factor with protease inhibitor wound dressings to growth factors with standard wound dressings.

Results

The project was funded by the Canadian Institutes for Health Research and enrollment is expected to be initiated in 2018. It is expected that results will be available in 2021.

Conclusions

It is expected that the results of this trial will inform as to whether modifying the wound environment through the use of protease inhibitors increases the effectiveness of topically applied growth factors in the healing of chronic wounds.

Trial Registration

ClinicalTrials.gov NCT02845466; https://clinicaltrials.gov/ct2/show/NCT02845466 (Archived by WebCite at http://www.webcitation.org/6yOPhSBUA)

Dose-Response Study of Human Growth Hormone in Venous Ulcers: Influence on Healing and Synthesis of Collagen Types I and III

Objective:

To investigate the dose-response effect of topical human growth hormone on healing and local collagen synthesis and to study procollagen propeptides as markers of healing in chronic venous ulcers.

Design:

Double-blind, placebo-controlled study.

Setting:

Multicentre study, University Hospitals of Copenhagen, Denmark.

Patients:

Eighty-seven patients with chronic venous ulcers.

Interventions:

Solutions of growth hormone (Norditropin), 0.17 IU/ml, 1 IU/ml and 11.2 IU/ml, 0.1 ml/cm2/day, or placebo (groups 1–4) was administered daily except weekends for 6 weeks.

Main outcome measures:

Healing rates evaluated as weekly ulcer area reduction and complete healing. Local collagen synthesis was evaluated by measurement of the propeptides of collagen types I and III (PICP and PIIINP) in wound washings twice weekly during the first 3 weeks.

Results:

No significant difference in ulcer area reduction between the groups was seen, although patients treated with 0.17 IU/ml healed faster than the other groups ( p = 0.14). Nine (45%), five (29%), seven (31%) and six (31%) ulcers in groups 1–4 respectively were healed at follow-up ( p = 0.06–0.1, log rank test). PICP and PIINP increased by 21.4% per week, (14.5–28% per week) and 20.2% per week, (12.2–28.2% per week) respectively compared with placebo, p < 0.05. Both PIIINP and PICP at 3 weeks correlated significantly with the healing rates, r = 0.44, p < 0.001 and r = 0.34, p < 0.005.

Conclusion:

The study failed to demonstrate a significant influence on healing, whereas collagen synthesis was stimulated dose-dependently by growth hormone. Procollagen propeptides are sensitive markers of growth hormone action and may be useful markers of healing in clinical investigations in chronic venous ulcers. Lower doses of growth hormone should be considered in future studies.

Dressings and topical agents for arterial leg ulcers

BACKGROUND

It is estimated that people in industrialised countries have a 1% chance of suffering from a leg ulcer at some time in their life. The majority of leg ulcers are associated with circulation problems; poor blood return in the veins causes venous ulcers (around 70% of ulcers) and poor blood supply to the legs causes arterial ulcers (around 25% of ulcers). Treatment of arterial leg ulcers is directed towards correcting the poor arterial blood supply, for example, by surgically correcting arterial blockages, and by supporting ulcer healing using topical agents (medicines in cream/ointment) and wound dressings. There are a large number of topical agents and wound dressings available and it is unclear what impact these have on ulcer healing.

OBJECTIVES

To determine whether topical agents and wound dressings affect the rate of healing in arterial ulcers. To compare healing rates, costs and patient-centred outcomes between wound dressings and topical agents.

SEARCH STRATEGY

Potential trials were sought through the Specialised Trials Registers of the Cochrane Wounds Group (last searched April 2002), the Cochrane Peripheral Vascular Diseases Group (last searched November 2006) and the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, Issue 4, 2006

SELECTION CRITERIA

Randomised controlled trials (RCTs), or controlled clinical trials (CCTs) of dressings and topical agents for arterial leg ulcers were eligible for inclusion. The participants had to have ulcers that were described as arterial, and the time to healing, proportion completely healed, or rate of reduction in ulcer area had to be reported. All wound dressings and topical agents were eligible for inclusion in this review.

DATA COLLECTION AND ANALYSIS

Information on the participants' characteristics, the interventions, and outcomes, as well as data on the trial methods, such as blinding of patients and clinicians, and allocation concealment were extracted using a standardised data extraction form.

MAIN RESULTS

One trial met the inclusion criteria. This small trial compared ketanserin ointment with vehicle alone, changed twice a day. The trial was too small and for too short a follow-up period to be able to determine whether there was any difference in healing rates.

AUTHORS' CONCLUSIONS

There is insufficient evidence to determine whether the choice of topical agent or dressing affects the healing of arterial leg ulcers. Inadequate description of the people in the one included trial means that the results cannot be easily applied to other clinical populations.

Advances in the management of leg ulcers--the potential role of growth factors

Venous ulcers are a major health problem because of the increased costs of the treatment and the refractory nature of the ulcers. The treatment cost is estimated to be around 1 billion dollars per year in the United States (US), and the average cost for one patient over a lifetime exceeds dollars 400,000. There has been an increasing trend in the use of growth factors in their management. Genetic engineering has revolutionised the research of wound healing, as the majority of recombinant growth factors are now available for in vitro and in vivo studies. Online searches of Medline, Pub Medical and Embase were carried out using the terms venous ulcers, leg ulcers, growth factors and growth hormone. The literature regarding the potential role of growth factors in the management of leg ulcers is reviewed. The important clinical studies are critically analysed with a view to appreciate the emerging therapies and the further research possibilities in the management of venous leg ulcers. Clinical results with the use of growth factors in non-healing wounds are encouraging. However, small sample sizes and inconsistent end points in different clinical studies have been the main hurdle in reaching a definite conclusion. Further research is needed to provide the definite evidence. Future developments may include different delivery methods for the growth factors, use of different combinations of growth factors administered simultaneously or, sequentially, bioengineered skin grafts and chemical induction of angiogenesis with the use of gene transfer techniques.

Dressings and topical agents for arterial leg ulcers

BACKGROUND

It is estimated that people in industrialised countries have a 1% chance of suffering from a leg ulcer at some time in their life. The majority of leg ulcers are associated with circulation problems; poor blood return in the veins causes venous ulcers (around 70% of ulcers) and poor blood supply to the legs causes arterial ulcers (around 25% of ulcers). Treatment of arterial leg ulcers is directed towards correcting the poor arterial blood supply, for example, by surgically correcting arterial blockages, and by supporting ulcer healing using topical agents (medicines in cream/ointment) and wound dressings. There are a large number of topical agents and wound dressings available and it is unclear what impact these have on ulcer healing.

OBJECTIVES

To determine whether topical agents and wound dressings affect the rate of healing in arterial ulcers. To compare healing rates, costs and patient-centred outcomes between wound dressings and topical agents.

SEARCH STRATEGY

Publications describing (or potentially describing) randomised controlled trials (RCTs), or controlled clinical trials (CCTs) of dressings and topical agents for arterial leg ulcers were sought through the Specialised Trials Registers of the Cochrane Wounds Group (last searched January 2002) and the Cochrane Peripheral Vascular Diseases Group (last searched April 2002).

SELECTION CRITERIA

RCTs or CCTs (trials with non-randomised concurrent comparison groups) were eligible for inclusion. The participants had to have ulcers that were described as arterial, and the time to healing, proportion completely healed, or rate of reduction in ulcer area had to be reported. All wound dressings and topical agents were eligible for inclusion in this review.

DATA COLLECTION AND ANALYSIS

Information on the participants' characteristics, the interventions, and outcomes, as well as data on the trial methods, such as blinding of patients and clinicians, and allocation concealment were extracted using a standardised data extraction form.

MAIN RESULTS

One trial met the inclusion criteria. This small trial compared ketanserin ointment with vehicle alone, changed twice a day. The trial was too small and for too short a follow-up period to be able to determine whether there was any difference in healing rates.

REVIEWER'S CONCLUSIONS

There is insufficient evidence to determine whether the choice of topical agent or dressing affects the healing of arterial leg ulcers. Inadequate description of the people in the one included trial means that the results cannot be easily applied to other clinical populations.

Cytokine manipulation of the wound

Most individuals expect that healing is an inevitable outcome; wound healing is taken for granted. Although wound healing is perceived as inevitable, it can be fraught with problems and altered at many points. In the past, optimization of wound healing focused on minimizing contamination, accurate tissue approximation, and providing protection. With the advent of recombinant technology, optimization can now include manipulation of the molecular and cellular wound environment. Although the exact manipulative scheme has not yet evolved, it is clear from the multiple attempts reported in this article that understanding and progress is being made.

Sustained release of human growth hormone (hGH) from collagen film and evaluation of effect on wound healing in db/db mice

Collagen films containing human growth hormone (hGH) were prepared and the release of hGH from these films and their effect on healing of full-thickness wounds in db/db mice were evaluated. The release profiles of hGH from the collagen films varied with composition and preparation conditions. The film prepared by air-drying of the mixture of hGH and collagen solution released hGH continuously over 3 days both in vitro and in vivo. By application of collagen film containing 3 mg of hGH twice at an interval of 6 days to wounds, area of wounds on day 21 was significantly reduced compared with that of non-treated wounds. Application of hGH alone at the same dose had no significant effect on wound healing. The maximum serum hGH concentration after single administration of the hGH collagen film was lower than that with hGH alone, and hGH persisted in serum over 3 days. These results suggest that hGH collagen film may be a useful topical formulation for the treatment of wounds.

Hormonal effects on skin aging

With aging, there is a decrease in the level of hormones, such as estrogen, testosterone, dehydroepiandrosterone sulfate, and growth hormone. The effect of this decrease on the skin has been poorly documented, although more data are available for estrogen than for other hormones. This article reviews the effect of decreasing hormone levels on the skin and the possible cutaneous benefits of hormone replacement therapy.

Growth factors and wound healing

This paper is based on the thesis Growth Factors and Formation of Granulation Tissue, University of Göteborg, 1992. For the last decade, it has been acknowledged that growth factors are essential for regulating the cellular events involved in the formation of granulation tissue and in wound healing. Recently, clinical trials were initiated to study the wound healing effect of applying growth factors and growth hormone to human wounds. However, in order to apply growth factors in these trials in an intelligent and effective manner, it is important to understand their physiology and their role in wound healing. This review paper is about the growth factors: IGF-I, IGF-II, PDGF, bFGF, TGF-beta, EGF, TGF-alpha, TNF-alpha, SF-HGF and Growth Hormone and their role and effect in soft tissue wound healing in animals and humans.

Growth factors and wound healing

BACKGROUND

Over the last decade, there has been an exponential increase in our knowledge of the biology of growth factors. The hope has been and remains that these potent biologic agents will effect a fundamental improvement in the way we treat wounds.

OBJECTIVE

We will discuss the biology of growth factors and the dramatic effects these proteins have on cell proliferation, cell chemotaxis, and on the formation of extracellular matrix molecules.

RESULTS

Growth factors are extremely potent biologic agents that show promise in accelerating wound repair in both animal and human studies. They improve granulation tissue, enhance tensile strength, and promote reepithelialization. Cosmetic effects are also to be expected by antagonizing and blocking the action of these peptides.

CONCLUSION

Growth factors are likely to become an important therapeutic tool for the dermatologic surgeon.