Association of the Society for Vascular Surgery Wound, Ischemia, and foot Infection classification with long-term outcomes for complex diabetic foot wounds.

Abstract

Published major amputation rates for patients with complex diabetic foot wounds (cDFW) range from 4% to 21%, depending on their presenting Wound, Ischemia, and foot Infection (WIfI) classification. We have previously reported our early institutional outcomes after 3 years of experience with a multidisciplinary approach to cDFW care. The aim of this study was to evaluate the association of WIfI stage with wound healing and major amputation using 10 years of data from our multidisciplinary limb preservation service. We included all limbs treated for a cDFW between July 2012 and December 2023. WIfI stages were assigned at the time of presentation. Kaplan-Meier analyses and multivariable Cox proportional hazards models were used to evaluate the associations of WIfI stage with time to wound healing (primary outcome) and major amputation (secondary outcome) after accounting for baseline comorbidity, medication, and wound characteristics and clustering by patient. We treated 1187 cDFW in 477 patients with diabetes during the study period (mean patient age, 60.3 ± 11.5 years; 58.5% male, 60.8% Black race), of which 32.2% were WIfI stage 1, 23.1% were WIfI stage 2, 24.0% were WIfI stage 3, and 20.7% were WIfI stage 4. Ipsilateral revascularization was performed in 31.8% of limbs overall (18.5% endovascular, 13.4% open surgery) and was more common with increasing WIfI stage (P < .001). Podiatric surgery was performed in 47.1% of limbs. Mean wound healing time was 146.5 ± 155.9 days and varied significantly according to WIfI stage (P < .001). After a median follow-up time of 19 months (range, 0-98 months), major amputation occurred in 3.6% of limbs, and increased with increasing WIfI stage (stage 1, 0.26%; stage 2, 2.92%; stage 3, 4.56%; and stage 4, 8.54%; P < .001). After adjustment, increasing WIfI stage was associated with a lower likelihood of wound healing (vs. WIfI stage 1, WIfI 2: hazard ratio [HR], 0.96; 95% confidence interval [CI], 0.77-1.20; WIfI 3: HR, 0.65; 95% CI, 0.52-0.6782; WIfI 4: HR, 0.62; 95% CI, 0.49-0.79) and increased likelihood of major amputation (vs. WIfI stage 1, WIfI 2: HR, 10.6; 95% CI, 1.31-85.18; WIfI 3: HR, 12.9; 95% CI, 1.59-104.7; WIfI 4: HR, 26.2; 95% CI, 3.34-204.6). WIfI stage remains significantly associated with the long-term wound healing and major amputation outcomes in patients presenting with complex DFW. Excellent limb salvage rates can be achieved across all WIfI stages with the integration of multidisciplinary limb preservation teams.