RCT to evaluate a hyaluronic acid containing gauze pad in leg ulcers of venous or mixed aetiology

Hard-to-Heal Wound Healing: Superiority of Hydrogel EHO-85 (Containing Olea europaea Leaf Extract) vs. a Standard Hydrogel. A Randomized Controlled Trial

Chronic wounds, especially those that are hard-to-heal, constitute a serious public-health problem. Although progress has been made in the development of wound dressings for healing, there is little high-quality evidence of their efficacy, with no evidence of superiority in the use of one hydrogel over another. To evaluate the superiority of a hydrogel (EHO-85), containing Olea europaea leaf extract (OELE), over a standard hydrogel (SH), the promotion and/or improvement of healing of difficult-to-heal wounds was compared in a prospective, parallel-group multicenter, randomized, observer-blinded, controlled trial ("MACAON"). Non-hospitalized patients with pressure, venous or diabetic foot-ulcers difficult-to-heal were recruited and treated with standard care, and EHO-85 (n = 35) or VariHesive (n = 34) as SH. Wound-area reduction (WAR; percentage) and healing rate (HR; mm2/day) were measured. EHO-85 showed a statistically significant superior effect over VariHesive. At the end of the follow-up period, the relative WAR decreased by 51.6% vs. 18.9% (p < 0.001), with a HR mean of 10.5 ± 5.7 vs. 1.0 ± 7.5 mm2/day (p = 0.036). EHO-85 superiority is probably based on its optimal ability to balance the ulcer bed, by modulating pH and oxidative stress. That complements the wetting and barrier functions, characteristics of conventional hydrogels. These results support the use of EHO-85 dressing, for treatment of hard-to-heal ulcers. Trial Registration AEMPS:PS/CR623/17/CE.

Dressings and topical agents containing hyaluronic acid for chronic wound healing

BACKGROUND

Hyaluronic acid is synthesised in plasma membranes and can be found in extracellular tissues. It has been suggested that the application of hyaluronic acid to chronic wounds may promote healing, and the mechanism may be due to its ability to maintain a moist wound environment which helps cell migration in the wound bed.

OBJECTIVES

To evaluate the effects of hyaluronic acid (and its derivatives) on the healing of chronic wounds.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was February 2022.

SELECTION CRITERIA

We included randomised controlled trials that compared the effects of hyaluronic acid (as a dressing or topical agent) with other dressings on the healing of pressure, venous, arterial, or mixed-aetiology ulcers and foot ulcers in people with diabetes.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 12 trials (13 articles) in a qualitative synthesis, and were able to combine data from four trials in a quantitative analysis. Overall, the included trials involved 1108 participants (mean age 69.60 years) presenting 178 pressure ulcers, 54 diabetic foot ulcers, and 896 leg ulcers. Sex was reported for 1022 participants (57.24% female). Pressure ulcers It is uncertain whether there is a difference in complete healing (risk ratio (RR) 1.17, 95% confidence interval (CI) 0.58 to 2.35); change in ulcer size (mean difference (MD) 25.60, 95% CI 6.18 to 45.02); or adverse events (none reported) between platelet-rich growth factor (PRGF) + hyaluronic acid and PRGF because the certainty of evidence is very low (1 trial, 65 participants). It is also uncertain whether there is a difference in complete healing between lysine hyaluronate and sodium hyaluronate because the certainty of evidence is very low (RR 2.50, 95% CI 0.71 to 8.83; 1 trial, 14 ulcers from 10 participants). Foot ulcers in people with diabetes It is uncertain whether there is a difference in time to complete healing between hyaluronic acid and lyophilised collagen because the certainty of evidence is very low (MD 16.60, 95% CI 7.95 to 25.25; 1 study, 20 participants). It is uncertain whether there is a difference in complete ulcer healing (RR 2.20, 95% CI 0.97 to 4.97; 1 study, 34 participants) or change in ulcer size (MD -0.80, 95% CI -3.58 to 1.98; 1 study, 25 participants) between hyaluronic acid and conventional dressings because the certainty of evidence is very low. Leg ulcers We are uncertain whether there is a difference in complete wound healing (RR 0.98, 95% CI 0.26 to 3.76), percentage of adverse events (RR 0.79, 95% CI 0.22 to 2.80), pain (MD 2.10, 95% CI -5.81 to 10.01), or change in ulcer size (RR 2.11, 95% CI 0.92 to 4.82) between hyaluronic acid + hydrocolloid and hydrocolloid because the certainty of evidence is very low (1 study, 125 participants). It is uncertain whether there is a difference in change in ulcer size between hyaluronic acid and hydrocolloid because the certainty of evidence is very low (RR 1.02, 95% CI 0.84 to 1.25; 1 study, 143 participants). We are uncertain whether there is a difference in complete wound healing between hyaluronic acid and paraffin gauze because the certainty of evidence is very low (RR 2.00, 95% CI 0.21 to 19.23; 1 study, 24 ulcers from 17 participants). When compared with neutral vehicle, hyaluronic acid probably improves complete ulcer healing (RR 2.11, 95% CI 1.46 to 3.07; 4 studies, 526 participants; moderate-certainty evidence); may slightly increase the reduction in pain from baseline (MD -8.55, 95% CI -14.77 to -2.34; 3 studies, 337 participants); and may slightly increase change in ulcer size, measured as mean reduction from baseline to 45 days (MD 30.44%, 95% CI 15.57 to 45.31; 2 studies, 190 participants). It is uncertain if hyaluronic acid alters incidence of infection when compared with neutral vehicle (RR 0.89, 95% CI 0.53 to 1.49; 3 studies, 425 participants). We are uncertain whether there is a difference in change in ulcer size (cm2) between hyaluronic acid and dextranomer because the certainty of evidence is very low (MD 5.80, 95% CI -10.0 to 21.60; 1 study, 50 participants). We downgraded the certainty of evidence due to risk of bias or imprecision, or both, for all of the above comparisons. No trial reported health-related quality of life or wound recurrence. Measurement of change in ulcer size was not homogeneous among studies, and missing data precluded further analysis for some comparisons.

AUTHORS' CONCLUSIONS

There is currently insufficient evidence to determine the effectiveness of hyaluronic acid dressings in the healing of pressure ulcers or foot ulcers in people with diabetes. We found evidence that hyaluronic acid probably improves complete ulcer healing and may slightly decrease pain and increase change in ulcer size when compared with neutral vehicle. Future research into the effects of hyaluronic acid in the healing of chronic wounds should consider higher sample size and blinding to minimise bias and improve the quality of evidence.

Superiority of a Novel Multifunctional Amorphous Hydrogel Containing Olea europaea Leaf Extract (EHO-85) for the Treatment of Skin Ulcers: A Randomized, Active-Controlled Clinical Trial

This 8-week, multicenter, randomized, active-controlled, observer-blinded clinical trial was designed to demonstrate the accelerating effect on wound healing of the novel Olea europaea leaf extract hydrogel (EHO-85) by comparing it to a widely used amorphous hydrogel. Results showed that EHO-85 significantly accelerated wound healing, regardless of ulcer etiology (pressure, venous leg or diabetic foot) and prognosis, doubling the median wound area reduction compared with a reference amorphous hydrogel (79.4% vs. 39.7%; difference: −39.7%, 95% CI: −71.1 to −21.3%; p < 0.001). The intention-to-treat analysis was conducted on 195 patients from 23 Spanish health centers/nursing homes. This novel treatment balances the ulcer microenvironment by modulating reactive oxygen species and pH. These actions complement the moistening and barrier functions inherent to amorphous hydrogels, whilst also conferring EHO-85 its documented granulation formation and pain relief properties. Furthermore, efficacy was achieved safely and in a cost-efficient manner due to its multi-dose format, which reduced the amount of product needed by 85.8% over 8 weeks compared to single-use hydrogel. The present randomized controlled trial is a relevant milestone in evidence-based practice for being the first to demonstrate (i) the effectiveness of an amorphous hydrogel in accelerating wound healing and (ii) the superiority of a specific hydrogel over another.

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.

Effectiveness of hyaluronic acid and its derivatives on chronic wounds: a systematic review

OBJECTIVE

Hyaluronic acid (HA) and its derivatives are used for chronic wounds, but evidence of their effectiveness remains unclear. The aim of this study was to provide more updated evidence for the effectiveness of HA (or its derivatives) compared with placebo or other agents for promoting healing in chronic wounds.

METHOD

The Cochrane Central Register of Controlled Trials, MEDLINE via Ovid Online, CINAHL and the EMBASE via EBSCO host databases were searched. Drug companies and experts in wounds were also contacted. Randomised controlled trials of HA (or its derivatives) compared with control were eligible for inclusion.

RESULTS

We identified nine randomised controlled trials involving 865 participants with chronic wounds were included in the review. The reporting for mixed arterial and venous ulcers seems to be better quality than that for venous leg ulcers (VLUs) and diabetic foot ulcers (DFUs). Studies provided little evidence regarding the claimed effects of HA or its derivaties on healing of chronic wounds. However, there is some evidence on their effectiveness for reducing pain intensity for mixed arterial and venous ulcers, which involved 255 patients (MD=-6.78 [95% CI: -11.10 to -2.46]).

CONCLUSION

Evidence to guide decisions regarding the use of HA or its derivatives to promote wound healing is still limited. More good-quality randomised controlled trials are warranted.

Debridement for venous leg ulcers

BACKGROUND

Venous ulcers (also known as varicose or venous stasis ulcers) are a chronic, recurring and debilitating condition that affects up to 1% of the population. Best practice documents and expert opinion suggests that the removal of devitalised tissue from venous ulcers (debridement) by any one of six methods helps to promote healing. However, to date there has been no review of the evidence from randomised controlled trials (RCTs) to support this.

OBJECTIVES

To determine the effects of different debriding methods or debridement versus no debridement, on the rate of debridement and wound healing in venous leg ulcers.

SEARCH METHODS

In February 2015 we searched: The Cochrane Wounds Group 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. There were no restrictions with respect to language, date of publication or study setting. In addition we handsearched conference proceedings, journals not cited in MEDLINE, and the bibliographies of all retrieved publications to identify potential studies. We made contact with the pharmaceutical industry to enquire about any completed studies.

SELECTION CRITERIA

We included RCTs, either published or unpublished, which compared two methods of debridement or compared debridement with no debridement. We presented study results in a narrative form, as meta-analysis was not possible.

DATA COLLECTION AND ANALYSIS

Independently, two review authors completed all study selection, data extraction and assessment of trial quality; resolution of disagreements was completed by a third review author.

MAIN RESULTS

We identified 10 RCTs involving 715 participants. Eight RCTs evaluated autolytic debridement and included the following agents or dressings: biocellulose wound dressing (BWD), non-adherent dressing, honey gel, hydrogel (gel formula), hydrofibre dressing, hydrocolloid dressings, dextranomer beads, Edinburgh University Solution of Lime (EUSOL) and paraffin gauze. Two RCTs evaluated enzymatic preparations and one evaluated biosurgical debridement. No RCTs evaluated surgical, sharp or mechanical methods of debridement, or debridement versus no debridement. Most trials were at a high risk of bias.Three RCTs assessed the number of wounds completely debrided. All three of these trials compared two different methods of autolytic debridement (234 participants), with two studies reporting statistically significant results: one study (100 participants) reported that 40/50 (80%) ulcers treated with dextranomer beads and 7/50 (14%) treated with EUSOL achieved complete debridement (RR 5.71, 95% CI 2.84 to 11.52); while the other trial (86 participants) reported the number of ulcers completely debrided as 31/46 (76%) for hydrogel versus 18/40 (45%) for paraffin gauze (RR 0.67, 95% CI 0.45 to 0.99). One study (48 participants) reported that by 12 weeks, 15/18 (84%) ulcers treated with BWD had achieved a 75% to 100% clean, granulating wound bed versus 4/15 (26%) treated with non-adherent petrolatum emulsion-impregnated gauze.Four trials assessed the mean time to achieve debridement: one (86 participants) compared two autolytic debridement methods, two compared autolytic methods with enzymatic debridement (71 participants), and the last (12 participants) compared autolytic with biosurgical debridement; none of the results achieved statistical significance.Two trials that assessed autolytic debridement methods reported the number of wounds healed at 12 weeks. One trial (108 participants) reported that 24/54 (44%) ulcers treated with honey healed versus 18/54 (33%) treated with hydrogel (RR (adjusted for baseline wound diameter) 1.38, 95% CI 1.02 to 1.88; P value 0.037). The second trial (48 participants) reported that 7/25 (28%) ulcers treated with BWD healed versus 7/23 (30%) treated with non-adherent dressing.Reduction in wound size was assessed in five trials (444 participants) in which two autolytic methods were compared. Results were statistically significant in one three-armed trial (153 participants) when cadexomer iodine was compared to paraffin gauze (mean difference 24.9 cm², 95% CI 7.27 to 42.53, P value 0.006) and hydrocolloid compared to paraffin gauze (mean difference 23.8 cm², 95% CI 5.48 to 42.12, P value 0.01). A second trial that assessed reduction in wound size based its results on median differences and, at four weeks, produced a statistically significantly result that favoured honey over hydrogel (P value < 0.001). The other three trials reported no statistically significant results for reduction in wound size, although one trial reported that the mean percentage reduction in wound area was greater at six and 12 weeks for BWD versus a non-adherent dressing (44% versus 24% week 6; 74% versus 54% week 12).Pain was assessed in six trials (544 participants) that compared two autolytic debridement methods, but the results were not statistically significant. No serious adverse events were reported in any trial.

AUTHORS' CONCLUSIONS

There is limited evidence to suggest that actively debriding a venous leg ulcer has a clinically significant impact on healing. The overall small number of participants, low number of studies and lack of meta-analysis in this review precludes any strong conclusions of benefit. Comparisons of different autolytic agents (hydrogel versus paraffin gauze; Dextranomer beads versus EUSOL and BWD versus non-adherent dressings) and Larvae versus hydrogel all showed statistically significant results for numbers of wounds debrided. Larger trials with follow up to healing are required.