Negative Pressure Wound Therapy versus Conventional Dressing in Diabetic Foot Ulcers: A Randomized Comparative Trial

Abstract

Background: Diabetic foot ulcers are a leading cause of non-traumatic lower extremity amputation, with particularly devastating consequences in sub-Saharan Africa where late presentation and limited resources compound the disease burden. Negative pressure wound therapy has demonstrated efficacy in accelerating wound healing, yet randomized data from African settings remain scarce. Methods: A prospective, randomized, open-label, comparative trial was conducted at a tertiary university teaching hospital in Lagos, Nigeria, from March to Feb 2023. Eighty patients with Wagner grade 2 to 3 diabetic foot ulcers were randomized 1:1 to receive either negative pressure wound therapy at minus 125 mmHg (n = 40) or conventional moist saline gauze dressing (n = 40) for up to 8 weeks. Both groups received standard diabetic foot care including offloading, glycaemic optimisation, and culture-directed antibiotics. The primary outcome was percentage wound area reduction at 4 weeks. Secondary outcomes included time to adequate granulation, time to wound closure, amputation rate, and hospital length of stay. Results: Baseline wound areas were comparable (28.4 ± 12.6 versus 26.8 ± 11.8 cm², p = 0.562). At 4 weeks, the NPWT group demonstrated significantly greater wound area reduction (62.4% versus 38.6%, p < 0.001). Time to adequate granulation was shorter with NPWT (12.4 ± 3.8 versus 18.6 ± 5.2 days, p < 0.001). Time to wound closure was significantly reduced (32.8 ± 10.4 versus 48.6 ± 14.2 days, p < 0.001). The amputation rate was significantly lower in the NPWT group (7.9% versus 23.7%, p = 0.048). Hospital length of stay was shorter with NPWT (18.4 ± 6.8 versus 28.2 ± 10.4 days, p < 0.001). No serious device-related adverse events were recorded. Conclusion: NPWT significantly accelerated diabetic foot ulcer healing, reduced amputation rates by two-thirds, and shortened hospital stay by nearly 10 days compared to conventional dressing. These findings support the adoption of NPWT as a standard adjunct in moderate-to-severe diabetic foot ulcer management, including in resource-constrained settings.