Cost-effective faster wound healing with a sustained silver-releasing foam dressing in delayed healing leg ulcers--a health-economic analysis

Mechanical and contact characteristics of foam materials within wound dressings: Theoretical and practical considerations in treatment

In the treatment of acute and chronic wounds, the clinical performance of a given foam-based dressing, and, ultimately, the wound healing and cost of care outcomes are strongly influenced by the mechanical performance of the foam material/s within that dressing. Most aspects of the mechanical performance of foam materials, for example, their stiffness, frictional properties, conformability, swelling characteristics and durability, and the overall mechanical protection provided by a foam-based dressing to a wound strongly depend on the microstructure of the foam components, particularly on their microtopography, density and porosity. This article, therefore, provides, for the first time, a comprehensive, self-inclusive compilation of clinically relevant theoretical and practical considerations, based on published analytical and experimental research as well as clinical experience related to the mechanical performance of foams in foam-based wound dressings. The current bioengineering information is useful for establishing understanding of the importance of mechanical properties of foams in foam-based dressings among clinicians and researchers in industry and academia, and other potential stakeholders in the wound care field, for example, regulators and buyers. This information is also particularly important for the development of standardised test methods for the evaluation of foam-based wound dressings and resulting standard mechanical performance metrics for these dressings.

Estimated costs in treating sickle cell disease leg ulcer

OBJECTIVE

To identify the costs of treating leg ulcers due to sickle cell disease from the perspective of the Unified Health System.

METHOD

An observational, descriptive, cost-effective economic assessment study conducted in a single center with ulcer patients. The data collected were extracted from the participant's medical records and recorded in a form prepared for this purpose. The cost of the products used in ulcer treatment was provided by the Solicitation/Purchasing Section and Pharmacy Sector of the study institution. The variables studied were ulcer area, number and interval between visits, patient's length of stay in the service, materials used in each visit, and the number of nurse appointments.

RESULTS

The sample consisted of 29 patients. The average initial area of ulcers was 14.47 cm2, 79% of the cases had complete epithelialization in an average time of 8.02 months, with an average cost of R$ 1,288.06. The average cost to reduce 1 cm2 of the lesion area was R$ 102.20. Silver activated carbon coating was the most cost-effective treatment.

CONCLUSION

The average cost for complete healing of a sickle cell ulcer with an average area of 14.95 cm2 was R$ 1,288.06.

A Systematic Review of Model-Based Economic Evaluations of Treatments for Venous Leg Ulcers

OBJECTIVE

The aim of this review was to identify, and assess the quality of, published model-based economic evaluations relating to treatments for patients with venous leg ulcers to help inform future decision-analytic models in this clinical area.

METHODS

A systematic literature search was performed on six electronic databases, from database inception until 21 May 2018. Search results were screened against predefined criteria by two independent reviewers. Data was then extracted from the included studies using a standardised form, whilst the decision-analytic model-specific Philips Checklist was used to assess quality and to inform model critique.

RESULTS

A total of 23 models were identified, 12 studies used a Markov modelling approach, five used decision trees and six studies did not detail the model type. Studies were predominantly from the National Health Service (NHS)/payer perspective, with only two taking a societal perspective. Interventions were wide ranging, but dressing technologies (11/23) were most common. The intervention studied was found to be dominant in 22/23 studies. The reporting quality of papers was mostly low, with evidence behind model structures, time horizons and data selection consistently underreported across the included papers.

CONCLUSIONS

This review has identified a sizeable literature of model-based economic evaluations, evaluating treatments for venous leg ulcers. However, the methods used to conduct such studies were generally poorly reported. In particular, the reporting of evidence surrounding the model structure, justification of the time horizon used and the rationale for selecting data inputs should be focused on in any future models developed.

VenUS IV (Venous leg Ulcer Study IV) - compression hosiery compared with compression bandaging in the treatment of venous leg ulcers: a randomised controlled trial, mixed-treatment comparison and decision-analytic model

BACKGROUND

Compression is an effective and recommended treatment for venous leg ulcers. Although the four-layer bandage (4LB) is regarded as the gold standard compression system, it is recognised that the amount of compression delivered might be compromised by poor application technique. Also the bulky nature of the bandages might reduce ankle or leg mobility and make the wearing of shoes difficult. Two-layer compression hosiery systems are now available for the treatment of venous leg ulcers. Two-layer hosiery (HH) may be advantageous, as it has reduced bulk, which might enhance ankle or leg mobility and patient adherence. Some patients can also remove and reapply two-layer hosiery, which may encourage self-management and could reduce costs. However, little robust evidence exists about the effectiveness of two-layer hosiery for ulcer healing and no previous trials have compared two-layer hosiery delivering 'high' compression with the 4LB.

OBJECTIVES

Part I To compare the clinical effectiveness and cost-effectiveness of HH and 4LB in terms of time to complete healing of venous leg ulcers. Part II To synthesise the relative effectiveness evidence (for ulcer healing) of high-compression treatments for venous leg ulcers using a mixed-treatment comparison (MTC). Part III To construct a decision-analytic model to assess the cost-effectiveness of high-compression treatments for venous leg ulcers.

DESIGN

Part I A multicentred, pragmatic, two-arm, parallel, open randomised controlled trial (RCT) with an economic evaluation. Part II MTC using all relevant RCT data - including Venous leg Ulcer Study IV (VenUS IV). Part III A decision-analytic Markov model.

SETTINGS

Part I Community nurse teams or services, general practitioner practices, leg ulcer clinics, tissue viability clinics or services and wound clinics within England and Northern Ireland.

PARTICIPANTS

Part I Patients aged ≥ 18 years with a venous leg ulcer, who were willing and able to tolerate high compression.

INTERVENTIONS

Part I Participants in the intervention group received HH. The control group received the 4LB, which was applied according to standard practice. Both treatments are designed to deliver 40 mmHg of compression at the ankle. Part II and III All relevant high-compression treatments including HH, the 4LB and the two-layer bandage (2LB).

MAIN OUTCOME MEASURES

Part I The primary outcome measure was time to healing of the reference ulcer (blinded assessment). Part II Time to ulcer healing. Part III Quality-adjusted life-years (QALYs) and costs.

RESULTS

Part I A total of 457 participants were recruited. There was no evidence of a difference in time to healing of the reference ulcer between groups in an adjusted analysis [hazard ratio (HR) 0.99, 95% confidence interval (CI) 0.79 to 1.25; p = 0.96]. Time to ulcer recurrence was significantly shorter in the 4LB group (HR = 0.56, 95% CI 0.33 to 0.94; p = 0.026). In terms of cost-effectiveness, using QALYs as the measure of benefit, HH had a > 95% probability of being the most cost-effective treatment based on the within-trial analysis. Part II The MTC suggests that the 2LB has the highest probability of ulcer healing compared with other high-compression treatments. However, this evidence is categorised as low to very low quality. Part III Results suggested that the 2LB had the highest probability of being the most cost-effective high-compression treatment for venous leg ulcers.

CONCLUSIONS

Trial data from VenUS IV found no evidence of a difference in venous ulcer healing between HH and the 4LB. HH may reduce ulcer recurrence rates compared with the 4LB and be a cost-effective treatment. When all available high-compression treatments were considered, the 2LB had the highest probability of being clinically effective and cost-effective. However, the underpinning evidence was sparse and more research is needed. Further research should thus focus on establishing, in a high-quality trial, the effectiveness of this compression system in particular.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN49373072.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 18, No. 57. See the NIHR Journals Library website for further project information.

Wound healing and cost-saving benefits of combining negative-pressure wound therapy with silver

A 20-patient case series is presented, demonstrating the incorporation of a silver antimicrobial negative-pressure dressing and a negative-pressure wound therapy device for improved healing outcomes, decreased nursing time expenditure, and decreased cost expenditure.

Cost-effective use of silver dressings for the treatment of hard-to-heal chronic venous leg ulcers

AIM

To estimate the cost-effectiveness of silver dressings using a health economic model based on time-to-wound-healing in hard-to-heal chronic venous leg ulcers (VLUs).

BACKGROUND

Chronic venous ulceration affects 1-3% of the adult population and typically has a protracted course of healing, resulting in considerable costs to the healthcare system. The pathogenesis of VLUs includes excessive and prolonged inflammation which is often related to critical colonisation and early infection. The use of silver dressings to control this bioburden and improve wound healing rates remains controversial.

METHODS

A decision tree was constructed to evaluate the cost-effectiveness of treatment with silver compared with non-silver dressings for four weeks in a primary care setting. The outcomes: 'Healed ulcer', 'Healing ulcer' or 'No improvement' were developed, reflecting the relative reduction in ulcer area from baseline to four weeks of treatment. A data set from a recent meta-analysis, based on four RCTs, was applied to the model.

RESULTS

Treatment with silver dressings for an initial four weeks was found to give a total cost saving (£141.57) compared with treatment with non-silver dressings. In addition, patients treated with silver dressings had a faster wound closure compared with those who had been treated with non-silver dressings.

CONCLUSION

The use of silver dressings improves healing time and can lead to overall cost savings. These results can be used to guide healthcare decision makers in evaluating the economic aspects of treatment with silver dressings in hard-to-heal chronic VLUs.

Use of silver in the prevention and treatment of infections: silver review

BACKGROUND

The use of silver for the treatment of various maladies or to prevent the transmission of infection dates back to at least 4000 b.c.e. Medical applications are documented in the literature throughout the 17th and 18th centuries. The bactericidal activity of silver is well established. Silver nitrate was used topically throughout the 1800 s for the treatment of burns, ulcerations, and infected wounds, and although its use declined after World War II and the advent of antibiotics, Fox revitalized its use in the form of silver sulfadiazine in 1968.

METHOD

Review of the pertinent English-language literature.

RESULTS

Since Fox's work, the use of topical silver to reduce bacterial burden and promote healing has been investigated in the setting of chronic wounds and ulcers, post-operative incision dressings, blood and urinary catheter designs, endotracheal tubes, orthopedic devices, vascular prostheses, and the sewing ring of prosthetic heart valves. The beneficial effects of silver in reducing or preventing infection have been seen in the topical treatment of burns and chronic wounds and in its use as a coating for many medical devices. However, silver has been unsuccessful in certain applications, such as the Silzone heart valve. In other settings, such as orthopedic hardware coatings, its benefit remains unproved.

CONCLUSION

Silver remains a reasonable addition to the armamentarium against infection and has relatively few side effects. However, one should weigh the benefits of silver-containing products against the known side effects and the other options available for the intended purpose when selecting the most appropriate therapy.

Moist occlusive dressing (Aquacel(®) Ag) versus moist open dressing (MEBO(®)) in the management of partial-thickness facial burns: a comparative study in Ain Shams University

INTRODUCTION

The face is the central point of the physical features; it transmits expressions and emotions, communicates feelings and allows for individual identity. Facial burns are very common and are devastating to the affected patient and results into numerous physical, emotional and psychosocial sequels. Partial thickness facial burns are very common especially among children. This study compares the effect of standard moist open technique management and a moist closed technique for partial thickness burns of the face.

PATIENTS AND METHODS

Patients with partial-thickness facial burns admitted in the burn unit, Ain Shams University, Cairo, Egypt in the period from April 2009 to December 2009 were included in this study. They were divided into two groups to receive either open treatment with MEBO(®) (n=20) or coverage with Aquacel(®) Ag (n=20). Demographics (age, gender, ethnicity, TBSA, burn areas), length of hospital stay (LOS), rate of infections, time to total healing, frequency of dressing changes, pain, cost benefit and patient discomfort were compared between the two groups. The long-term outcome (incidence of hypertrophic scarring) was assessed for up to 6 months follow-up period.

RESULTS

There were no significant differences in demographics between the two groups. In the group treated with the Aquacel(®) Ag, the mean time for re-epithelialization was 10.5 days, while it was 12.4 days in the MEBO(®) group (p<0.05). Frequency of changes, pain and patient discomfort were less with Aquacel(®) Ag. Cost was of no significant difference between the two groups. Scar quality improved in the Aquacel(®) Ag treatment group. Three and 6 months follow-up was done and long-term outcomes were recorded in both groups.

CONCLUSION

Moist occlusive dressing (Aquacel(®) Ag) significantly improves the management and healing rate of partial thickness facial burns with better long-term outcome compared to moist open dressing (MEBO(®)).

An overview of the evidence on the efficacy of silver dressings

While there is a plethora of clinical and anecdotal evidence on the efficacy of silver dressings, there is no rigorous RCT data to support this. This has led procurement managers to defer the inclusion of silver dressings on wound formularies, despite its clinical popularity. This article gives an overview of the evidence on topical antimicrobials, in order to determine whether there is a case for such a stance.

A review of the applications of the hydrofiber dressing with silver (Aquacel Ag) in wound care

Aquacel Ag((R)) (ConvaTec, Princeton, NJ, USA) is a new hydrofiber wound dressing consisting of soft non-woven sodium carboxymethylcellulose fibers integrated with ionic silver. It is a moisture-retention dressing, which forms a gel on contact with wound fluid and has antimicrobial properties of ionic silver. We present a current literature review on Aquacel Ag((R)), of both in vitro and in vivo efficacy and clinical applications. In vitro and in vivo studies have demonstrated the wide antimicrobial properties of Aquacel Ag((R)), and additionally demonstrated the cytotoxicity of ionic silver to keratinocytes and fibroblasts that cause delay in wound re-epithelialization. Clinical studies confirmed that Aquacel Ag((R)) is an effective and safe dressing for a variety of wound types, both acute and chronic. Incorporation of ionic silver into the hydrofibers does not cause undue alteration in the performance properties of the base dressing, which continues to provide favorable wound moisture and exudate management. The addition of ionic silver reduces local pain and dressing changes, and provides significant broad-spectrum antimicrobial properties, with no delay in wound healing.

Regular debridement is the main tool for maintaining a healthy wound bed in most chronic wounds

Sharp debridement is the most clinically and cost-effective way of physically removing and suppressing a biofilm. Continued debridement, as part of a multifaceted treatment strategy, will keep the biofilm in a weakened state.

The safety and efficacy of dressings with silver - addressing clinical concerns

With the increasing use of silver as a topical application in wound care, concerns focussing on its role are bound to arise. These concerns, which centre on issues such as resistance and toxicity, clinical efficacy and cost-effectiveness, need to be addressed and openly discussed so that they are viewed from a rational perspective. While clinical efficacy and safety, along with cost-benefit, are of obvious interest, the origin of some of these concerns is a matter of debate. The silver-containing dressing segment of the medical device market is of huge commercial importance, and, consequently, marketing and promotional issues occasionally obscure the evidence that clinicians need to have in order that they may provide appropriate treatment for their patients. The impact of silver application on the wound bioburden needs to be examined carefully to heighten our awareness of any deleterious effects on the healing process, without inducing any unfounded anxieties.

Chitosan malate inhibits growth and exotoxin production of toxic shock syndrome-inducing Staphylococcus aureus strains and group A streptococci

Previously, it has been shown that the polysaccharide chitosan inhibits the growth of gram-positive bacteria. In this study, chitosan malate was evaluated in broth and thin-film cultures for its effect on the growth and exotoxin production of toxic shock syndrome (TSS)-inducing Staphylococcus aureus (five strains, three producing TSS toxin 1 and one each producing enterotoxin B or C) and group A streptococci (three strains producing streptococcal pyrogenic exotoxin A). Also, the compound was evaluated in a rabbit subcutaneous Wiffle ball model for its ability to prevent S. aureus and group A streptococcal induction of TSS. Finally, chitosan malate was evaluated for its ability to prevent TSS and necrotizing fasciitis in rabbits after subcutaneous inoculation with microbes. Chitosan malate inhibited both bacterial growth and, at sub-growth-inhibitory concentrations, the production of exotoxins, in both broth and thin-film cultures. Rabbits treated with chitosan malate in implanted Wiffle balls were protected from prior challenge with TSS-inducing S. aureus compared to animals not receiving chitosan malate (P < 0.001) and group A streptococci (P < 0.005). Chitosan malate protected rabbits from the development of streptococcal TSS with necrotizing fasciitis (P < 0.01). The data suggest that use of this growth- and toxin-inhibitory compound may be able to reduce the severity of S. aureus and group A streptococcal mucous membrane and trauma-associated skin infections.

Silver dressings: their role in wound management

Dressings have a part to play in the management of wounds; whether they are sutured or open, usually chronic wounds of many aetiologies which are healing by secondary intention. They traditionally provide a moist wound environment, but this property has been extended through simple to complex, active dressings which can handle excessive exudate, aid in debridement, and promote disorganised, stalled healing. The control of infection remains a major challenge. Inappropriate antibiotic use risks allergy, toxicity and most importantly resistance, which is much reduced by the use of topical antiseptics (such as povidone iodine and chlorhexidine). The definition of what is an antimicrobial and the recognition of infection has proven difficult. Although silver has been recognised for centuries to inhibit infection its use in wound care is relatively recent. Evidence of the efficacy of the growing number of silver dressings in clinical trials, judged by the criteria of the Cochrane Collaboration, is lacking, but there are good indications for the use of silver dressings, to remove or reduce an increasing bioburden in burns and open wounds healing by secondary intention, or to act as a barrier against cross contamination of resistant organisms such as MRSA. More laboratory, and clinical data in particular, are needed to prove the value of the many silver dressings which are now available. Some confusion persists over the measurement of toxicity and antibacterial activity but all dressings provide an antibacterial action, involving several methods of delivery. Nanocrystalline technology appears to give the highest, sustained release of silver to a wound without clear risk of toxicity.

Effect of a sustained silver-releasing dressing on ulcers with delayed healing: the CONTOP study

OBJECTIVE

To compare the effect of the sustained silver-releasing foam dressing Contreet Foam (ColoplastA/S) with local best practice (LBP) on delayed healing ulcers using a real-life setting.

METHOD

A total of 619 patients with ulcers of varying aetiologies were treated for four weeks with either the silver foam dressing or LBP.

RESULTS

Wound area was reduced by 50% with the silver foam and 34% with LBP Less slough and maceration, a faster reduction in exudate level and more positive wound progress was achieved with the silver foam. In addition, exudate handling, ease of use, odour and pain improved. Less time was spent on dressing changes, and mean wear time was longer for the silver foam (3.1 days) than for LBP (2.1 days). All differences were statistically significant (p < 0.05). The silver foam dressing outperformed all of the other dressing categories including moist wound healing products and other silver dressings.

CONCLUSION

This large-scale comparative real-life study shows that the silver foam dressing supports faster healing of delayed healing wounds.