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The effectiveness of silver-releasing dressings in the management of non-healing chronic wounds: a meta-analysis |
Lo SF, Chang CJ, Hu WY, Hayter M, Chang YT |
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CRD summary This review concluded that silver dressings were effective in promoting wound healing and improving patients' quality of life, although further randomised controlled trials are required. This conclusion reflects the results of the review, which was generally well-conducted, and appears likely to be reliable. Authors' objectives To assess the efficacy of silver-releasing dressings in the management of non-healing chronic wounds. Searching MEDLINE, CINAHL, the Cochrane Library, British Nursing Index, EBSCO, OCLC (Online Computer Library Catalogue) and ProQuest were searched for dates ranging from 1950 to June 2007. Dissertation and conference abstracts were searched for unpublished studies. Periodicals and textbooks were handsearched, references were checked and manufacturers and experts were contacted. Wound management websites were also searched. Only studies reported in English or Chinese were eligible for inclusion. Study selection Randomised controlled trials (RCTs) that compared silver dressings with non-silver dressings or traditional wound management in patients with wounds that had delayed healing, or a clinically diagnosed colonisation or infection, were eligible for inclusion. Trials reporting physical, psychological or economic outcomes were eligible for inclusion.
Included trials were conducted in Europe, USA, Canada and Brazil. All included trials compared silver-releasing dressings with non-silver-releasing dressings of various types. Comparators included foam dressings, alginate dressings and hydropolymer adhesive dressings. Intervention duration ranged from four to eight weeks. Patients in included trials had venous leg ulcers, arterial ulcers, pressure ulcers, diabetic foot ulcers, and other types of chronic non-healing wounds. Where reported, mean ages of patients ranged from 58.9 to 74.9 years, and the majority of patients were females. Outcomes assessed included wound area, odour, maceration, exudates, wound bed tissues composition and pain (physical); the EQ-5D (standardised instrument for use as a measure of health outcome - psychological); dressing wear time (economic); and adverse events. Other outcomes were also reported by included trials.
Two reviewers independently assessed the studies for inclusion at both abstract and full-text stages. Assessment of study quality Two independent reviewers assessed the trials for validity using the CONSORT (Consolidated Standards of Reporting Trials) criteria and another published checklist. A total of 15 items were used in the assessment, giving a possible total score of 30 points. Only those trials with a score of at least 18 points (60%) were included in the analysis. Data extraction Data were extracted to permit the calculation of effect sizes (ES) with 95% confidence intervals (CI).
Two reviewers independently extracted the data using a piloted, prespecified form. Authors were contacted for further information. Methods of synthesis Fixed-effect meta-analyses were used to calculate pooled effect sizes with 95% confidence intervals. If statistically significant heterogeneity had been detected, a random-effects model would have been adopted. Statistical heterogeneity was assessed using Cochran's Q, with a significance threshold of P<0.05. Subgroup analyses based on dressing type and patient group were conducted. Publication bias was assessed using visual inspection of funnel plots and Egger's test. Results of the review Eight RCTs were included in the review (n=1,399 patients). Validity scores ranged from 21 to 28. Four of the included trials were considered to be of high quality.
Physical outcomes: There was a statistically significant benefit for the silver dressing group in wound area reduction (ES 0.28, 95% CI 0.16 to 0.39; six RCTs), wound odour improvement (ES 0.38, 95% CI 0.24 to 0.52; three RCTs), wound exudate level (ES 0.31, 95% CI 0.17 to 0.44; three RCTs) and wound pain reduction (ES 0.33, 95% CI 0.18 to 0.47; two RCTs).
Other outcomes: There was a significant benefit in health outcomes assessed by the standardised measurement instrument (EQ-5D) for the silver dressing groups (ES 0.18, 95% CI 0.04 to 0.33; two RCTs). There was also a significant benefit in longer dressing wear time (ES 0.33, 95% CI 0.19 to, 0.48; two RCTs). Four RCTs reported information on adverse events; none reported any serious adverse events. The principal local adverse events reported were deterioration of peri-ulcer skin and a burning sensation.
There was no evidence of statistically significant heterogeneity between the trials on any outcome. There was no evidence of an effect of dressing type on any outcome in the subgroup analyses.
There was no evidence of publication bias. Authors' conclusions The effectiveness of silver dressings in wound healing and improving patients' quality of life was confirmed. However, the need for addition well-designed RCTs to further evaluate their effectiveness was also highlighted. CRD commentary The review question and inclusion criteria were clear. The authors searched a number of databases and other relevant sources including a systematic attempt to locate unpublished studies. This reduced the chances of relevant studies being omitted and of publication bias. However, the decision to limit the review to studies published in English or Chinese may have increased the possibility of language bias. Publication bias was assessed and no evidence of it was found. Rigorous methodology was employed at all stages of the review process. A validity assessment was conducted and was used as an additional inclusion criterion. Limited information was provided on the criteria used in the assessment but, from the details reported, they appeared appropriate. The decision to employ meta-analysis appeared appropriate. Heterogeneity was assessed and no evidence was found; while a standard assessment was used, the threshold used to denote significance was less conservative than usual. The authors' conclusions reflect the evidence of the review and are probably reliable. Implications of the review for practice and research Practice: The authors stated that there is clear evidence that silver-releasing dressings are effective when applied to chronic non-healing wounds but that an adverse events assessment should be conducted when they are used.
Research: The authors stated that there is a need for further well-designed RCTs to assess the effectiveness of silver-releasing dressings for non-healing chronic wounds in different clinical settings and patient populations; such trials should clearly report all variables. Research is also required to assess the effectiveness of these dressings in non-European healthcare circumstances. Cost-effectiveness studies are also required to inform healthcare practice. Bibliographic details Lo SF, Chang CJ, Hu WY, Hayter M, Chang YT. The effectiveness of silver-releasing dressings in the management of non-healing chronic wounds: a meta-analysis. Journal of Clinical Nursing 2009; 18(5): 716-728 Other publications of related interest Lo SF, Hayter M, Chang CJ, Hu WY, Lee LL. A systematic review of silver-releasing dressings in the management of infected chronic wounds. Journal of Clinical Nursing 2008;17(15):1973-1985. Indexing Status Subject indexing assigned by NLM MeSH Aged; Bandages /classification /standards; Chronic Disease; Female; Humans; Male; Middle Aged; Publication Bias; Randomized Controlled Trials as Topic; Silver Compounds /administration & Treatment Outcome; Wound Healing /drug effects; Wounds and Injuries /nursing /therapy; dosage AccessionNumber 12009105633 Date bibliographic record published 26/08/2009 Date abstract record published 10/02/2010 Record Status This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn. |
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