| Does Cost Drive Efficacy? |
Evaluating the Antimicrobial Efficacy and Cost of Three Silver
Dressings and AmeriGel® Saturated Gauze Dressing With Oakin®
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by Jonathan Moore DPM, MS, AAPWCA
Cumberland Foot Health Solutions, Somerset, KY
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Jonathan Moore
DPM, MS, AAPWCA
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Antimicrobial wound dressings are becoming more popular and are routinely used in the treatment of chronic and problematic wounds. Despite a wide variety of silver dressings available and various in-vitro responses from these dressings, randomized clinical trials to support the efficacy or clinical benefits of one silver product over another are lacking, raising questions about the wide variations in cost of these antimicrobial dressings.
Study Design
For the purposes of this study, a blinded, in-vitro Corrected Zone of Inhibition (CZOI) test was chosen to compare the antimicrobial properties of four widely used dressings. The blinded CZOI test was selected in lieu of a Standard Zone of Inhibition Test because the sizes of the zones were corrected to take into account the differences in shape and size of the hand-cut pieces of test material. All of the dressings were sterile and used as supplied by the manufacturer. The dressings studied were Prisma® (Systagenix Wound Management, Quincy, MA), Acticoat 7® (Smith and Nephew, Largo, FL), Aquacel® Ag (ConvaTec, Skillman, NJ), AmeriGel® Saturated Gauze Dressing (Amerx Health Care, Clearwater, FL). A sterile gauze pad was used as the control. The dressings were cut into 1cm X 1cm squares and placed upon lawns of bacterial cultures: Staphylococcus aureus (SA), Methicillin-Resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PA), seeded on Mueller Hinton Agar plates (MHA, Difco, Chicago, IL). Product squares were coded as follows: A = Prisma®, B = AmeriGel®, C = Acticoat® 7, D = Aquacel® Ag and E = sterile gauze.
The bacterial lawns were incubated for 24 hours. The CZOI was determined by measuring the zone of clearing across one direction of the test article and subtracting the exact width of the test article. This was done in two perpendicular directions across the dressing and the results averaged to yield the final value. The CZOI reflects only the width of the zone of clearing surrounding the test article and is corrected for variances in the exact size of the individual test articles. The CZOI was measured and the process repeated for 48 hours. This test is a modification of the standard Kirby-Bauer test for susceptibility of the test organism to the tested antimicrobial agent. The test also provides a measure of the ability of the antimicrobial agent to diffuse into the surrounding agar medium, producing larger or smaller zones of inhibition dependent upon the release and migration of the antimicrobial agent in the medium.
Study Findings
This study was able to demonstrate the ability of each antimicrobial dressing to inhibit the growth of bacteria in the area immediately surrounding the dressing. The results, shown in Table 1, indicate that all of the products (with the exception of the control) were able to produce a comparable zone of inhibition around each dressing piece for 24 hours and that the activity was maintained for 48 hours, as shown in Table 2. As is evident by the CZOI, all antimicrobial dressings demonstrated effective inhibition with no substantial clinical differences.
Cost Analysis
A cost analysis was performed, based on a review of the prices recorded from three widely known vendors, evaluating the average cost for each of the tested antimicrobial wound dressings. The graph below (Table 3) illustrates the average cost per dressing, based on the manufacturer’s application instructions, over a seven week period projected for 100 patients. The costs graphed do not include other dressing supplies, practitioner’s time or other incidental expenses.
Table 3 Cost projection for 100 patients
The results suggest the biggest differences between these antimicrobial dressings may be more in cost than in antimicrobial efficacy. The differences in cost are due to variances in cost per application and frequency of applications required per week. Taking into consideration the lack of a substantial difference of clinical benefit in the CZOI measurements among the antimicrobial dressings chosen for this study and the costs associated with these dressings, this study should help guide the physician in selecting an efficacious and economical antimicrobial wound dressing.
Conclusion
With the rising costs associated with wound care, reducing healing times utilizing a rational and evidence-based approach should be of prime importance to the wound care provider. While in some cases, higher initial costs for wound care products can be justified in order to reduce healing times, economic discretion is important when assessing cost versus efficacy when using products that work comparably. While the author does subscribe to the idea of using the best products available for the needs of the patient, choosing a product indicated for the same wound type that costs significantly higher than a comparable, less expensive product for any reason should be discouraged.
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| Amerigel® Skin and Wound Care products contain Oakin®, a proprietary oak extract proven to treat a variety of skin conditions. The tannins found in the Oakin® enhance the natural healing of wounds, ulcers, burns, sores, cuts, rashes and is recommended for problematic skin conditions caused by diabetes. This unique ingredient has earned AmeriGel® Wound Dressing a #1 rating by podiatrists across the country for use as a topical wound/ulcer and post-surgical treatment. |
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To learn more about Amerigel® products, follow this link or call 1-800-448-9599. |
