Perhaps these data confirm the adage that “It’s not what we put on the wound that heals it, but what we take off”.
This study sought to compare the efficacy of topical platelet derived growth factor (Regranex, Smith and Nephew, London, UK) (test group) to placebo (control group) in treating diabetic foot ulcers. All subjects had a short leg walking cast with a window fashioned in the cast over the site of the ulcer.
Forty-six subjects were randomized (double-blind) 1:1 to the test or control group and treated for up to 4 months. Subjects had Wagner grade I ulcers with wound area of 1 cm2 to 16 cm2 without severe peripheral arterial disease, osteomyelitis, or any infection requiring antibiotics. Study medication was applied daily and casts changed approximately every 14 days.
Of the 46 subjects randomized, 38 either healed or completed 16 weeks of therapy without healing. Eight subjects dropped out prior to 16 weeks. Based on intention-to-treat, 12 of 23 (52%) test group subjects healed before 16 weeks compared to 13 of 23 (57%) control group subjects (not significant). Regression analysis demonstrated that slower healing was associated with larger initial wound size (hazard radio [HR] = 0.997, 95% confidence interval [CI]: 0.995-1.00, P = 0.028) and excessive wound drainage (HR = 0.346, 95% CI: 0.126-0.948, P = 0.039). Excluding the patients who dropped out, 25 of 38 (66%) subjects healed by 4 months. Three additional subjects healed with casts that were worn longer than 4 months, for an overall rate of 74% at 9 months. Five subjects developed cast burns, and 3 patients required amputation.
Topical platelet derived growth factor does not appear to significantly improve healing of Wagner grade I diabetic foot ulcers that are treated by offloading with a short leg walking cast. Excellent healing rates may be achieved with casting alone.