Evidence Corner: Diabetic Foot Ulcers

Dear Readers: Foot problems are the most frequent cause of hospitalization in diabetic patients. Peripheral neuropathy leads to loss of protective sensation, and unheeded trauma results in ulceration with a high potential for infection and amputation. Consistent offloading has reportedly healed up to 80 percent of diabetic foot ulcers within 10 weeks,1 but patient adherence to the offloading protocols is inconsistent, and the total contact casts, which assure adherence to achieve these sterling results, require skill to apply. Below are two recent additions to the continuing search for topical modalities to heal these difficult wounds, identifying one debridement modality with healing benefits. While the search for effective topical care continues, clinicians face the challenge of offloading pressure points on the plantar surface consistently and well. Without effective offloading, topical treatment makes small headway against repeated trauma of the patient’s weight on the affected foot surface. Laura L. Bolton, PhD Department Editor Randomized Controlled Trial of Collagen/Oxidized Regenerated Cellulose Dressing Reference: Veves A, Sheehan P, Pham HT, for the Promogran® Diabetic Foot Ulcer Study. A randomized, controlled trial of Promogran (a collagen/oxidized regenerated cellulose dressing) vs. standard treatment in the management of diabetic foot ulcers. Arch Surg 2002;137:822–7. Rationale: Primary dressings are needed that might afford healing benefits for diabetic foot ulcers better than the effects of standard primary dressing with moistened gauze. Objective: This study compared the effect of a collagen/oxidized regenerated cellulose dressing (C/ORC) versus saline-moistened gauze primary dressings on complete wound closure of foot ulcers of diabetic patients being treated in university teaching hospitals and primary care centers. Methods: After a baseline medical history, which included reporting ulcer duration, type and prior management, and patient activity level and ambulatory status, 138 patients were randomly assigned to each dressing group, receiving either saline-moistened gauze or C/ORC dressing. Offloading techniques were standardized to the accepted protocol within the center but varied between centers. Both dressings were changed when clinically required for a maximum period of 12 weeks. Healing efficacy, safety, and patient and physician preferences were recorded. Results: There were no significant differences in safety and efficacy of the two dressings, with 90 percent of patients in both groups adhering to the protocol. Among the C/ORC-dressed ulcers, 37 percent healed after 12 weeks as compared to 28.3 percent of moist gauze-dressed ulcers (p = 0.12). In the subset of ulcers with lower than six-month duration, 45 percent of the 95 C/ORC-dressed ulcers healed at 12 weeks, as compared to 33 percent of 89 moist gauze-dressed ulcers (p = 0.056). Both patients and physicians preferred the C/ORC dressings. Conclusions: As a primary dressing on diabetic foot ulcers, the C/ORC dressing was comparable in safety and healing effects to saline-moistened gauze, though both patients and physicians preferred C/ORC. Clinical perspective: In clinical studies of wound healing on diabetic patients with plantar ulcers, there can be wide variability in the wound response to different offloading techniques or patient adherence to these offloading regimens, as well as blood glucose control and peripheral circulation differences. These sources of variability can overshadow effects of primary wound dressings on wound outcomes, a fact that alerts clinicians to the value of quality, consistent offloading of the diabetic lower extremity. Evidence Summary: Healing Effects of Diabetic Foot Debridement Reference: Smith J. Debridement of diabetic foot ulcers (Cochrane Review). In: The Cochrane Library, Issue 2, 2003. Oxford: Update Software. (www.cochrane.org. Accessed April 25, 2003) Rationale: Foot ulceration is believed to affect 15 percent of people with diabetes at some time during their lives. Debridement of necrotic tissue is necessary before a diabetic foot ulcer can heal. Objective: This systematic Cochrane review of the literature explored effectiveness of debridement as a treatment for improving healing of diabetic foot ulcers. Methods: All randomized controlled trials (RCTs) comparing effect of debridement modalities on either complete diabetic foot ulcer healing or rate of diabetic foot ulcer healing were included in the review, without language or publication status restrictions. Results: The following five RCTs were found assessing effectiveness of debridement on diabetic foot ulcer healing: Pooled results from three RCTs suggest that autolytic debridement using hydrogels is significantly more effective than gauze or standard care in healing diabetic foot ulcers. Small trials on surgical or larval debridement showed no significant benefit to diabetic ulcer healing. No RCTs were found evaluating effects of other debridement methods, such as enzymes or polysaccharide beads, on diabetic foot ulcer healing. Conclusions: The reviewer concludes that there is evidence that autolytic debridement using hydrogel increases the healing rate of diabetic foot ulcers. Clinical perspective: Necrotic tissue removal has long been suspected to aid healing. Considerable research has measured debriding effects without examining healing efficacy.2 This Cochrane review is a rare summary of findings supporting necrotic tissue removal as an aid to healing, the real “bottom line” for patients with diabetic foot ulcers. Perhaps this summary will stimulate research into the relative benefits of those debriding modalities that, as yet, lack proof of healing efficacy for diabetic foot ulcers. References: 1. Laing P. Diabetic foot ulcers. Amer J Surgery 1994;167 (Suppl 1A):31S–36S. 2. Bolton L, Fattu AJ. Topical agents and wound healing. Clin Dermatol 1994;12:95–120.