Background: Costs related to diabetic foot ulcer (DFU) care are greater than $1 billion annually and rising. We sought to describe the impact of diabetes mellitus (DM) on foot ulcer admissions in the United States, and to investigate potential explanations for rising hospital costs. Methods: The Nationwide Inpatient Sample (2005–2010) was queried using International Classification of Diseases, 9th Revision (ICD-9) codes for a primary diagnosis of foot ulceration. Multivariable analyses were used to compare outcomes and per-admission costs among patients with foot ulceration and DM versus non-DM. Results: In total, 962,496 foot ulcer patients were admitted over the study period. The overall rate of admissions was relatively stable over time, but the ratio of DM versus non-DM admissions increased significantly (2005: 10.2 vs. 2010: 12.7; P < 0.001). Neuropathy and infection accounted for 90% of DFU admissions, while peripheral vascular disease accounted for most non-DM admissions. Admissions related to infection rose significantly among DM patients (2005: 39,682 vs. 2010: 51,660; P < 0.001), but remained stable among non-DM patients. Overall, DM accounted for 83% and 96% of all major and minor amputations related to foot ulcers, respectively, and significantly increased cost of care (DM: $1.38 vs. non-DM: $0.13 billion/year; P < 0.001). Hospital costs per DFU admission were significantly higher for patients with infection compared with all other causes ($11,290 vs. $8,145; P < 0.001). Conclusions: Diabetes increases the incidence of foot ulcer admissions by 11-fold, accounting for more than 80% of all amputations and increasing hospital costs more than 10-fold over the 5 years. The majority of these costs are related to the treatment of infected foot ulcers. Education initiatives and early prevention strategies through outpatient multidisciplinary care targeted at high-risk populations are essential to preventing further increases in what is already a substantial economic burden.

Among patients with DFU, the WIfI classification system correlated well with wound healing but was not associated with risk of major amputation at 1 year. Although further prospective research is warranted, our results suggest that use of a multidisciplinary approach for DFUs may augment healing time and reduce amputation risk compared with previously published historical controls of standard wound care among patients with advanced stage 4 disease.

There does not appear to be a clinically meaningful association between baseline or prospective A1C and wound healing in patients with DFUs. The paradoxical finding of accelerated wound healing and increase in A1C in participants with better baseline glycemic control requires confirmation in further studies.

Objective: Previous studies show conflicting results in wound healing outcomes based on angiosome direct perfusion (DP), but few have adjusted for wound characteristics in their analyses. We have previously shown that the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification correlates with wound healing in diabetic foot ulcers (DFUs) treated by a multidisciplinary team. The aim of this study was to compare WIfI classification vs DP and pedal arch patency as predictors of wound healing in patients presenting with DFU and peripheral arterial disease. Methods: We performed a retrospective review of a prospectively maintained database of all patients with peripheral arterial disease presenting to our multidisciplinary DFU clinic who underwent angiography. An angiosome was considered directly perfused if the artery feeding the angiosome was revascularized or was completely patent. Wound healing time at 1 year was compared on the basis of DP vs indirect perfusion, Rutherford pedal arch grade, and WIfI classification using univariable statistics and Cox proportional hazards models. Results: Angiography was performed on 225 wounds in 99 patients (mean age, 63.3 6 1.2 years; 62.6% male; 53.5% black) during the entire study period. There were 33 WIfI stage 1, 33 stage 2, 51 stage 3, and 108 stage 4 wounds. DP was achieved in 154 wounds (68.4%) and indirect perfusion in 71 wounds (31.6%). On univariable analysis, WIfI classification was significantly associated with improved wound healing (57.2% for WIfI 3/4 vs 77.3% for WIfI 1/2; P ¼ .02), whereas DP and pedal arch patency were not (both, P $ .08). After adjusting for baseline patient and wound characteristics, WIfI stage remained independently predictive of wound healing (WIfI 3/4: hazard ratio [HR], 0.77; 95% confidence interval [CI], 0.67-0.88), whereas DP (HR, 0.82; 95% CI, 0.55-1.21) and pedal arch grade (HR, 0.85; 95% CI, 0.70-1.03) were not. Conclusions: In our population of patients treated by a multidisciplinary diabetic foot service, the Society for Vascular Surgery WIfI classification system was a stronger predictor of diabetic foot wound healing than DP or pedal arch patency. Our results suggest that a measure of wound severity should be included in all future studies assessing wound healing as an outcome, as differences in patients' wound characteristics may be a strong contributor to the variation of angiosomedirected perfusion results previously observed.

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