A comparison of two diabetic foot ulcer classification systems: the Wagner and the University of Texas wound classification systems

Abstract

Objective: In this study the following two ulcer classification systems were applied to new foot ulcers to compare them as predictors of outcome: the Wagner (grade) and the University of Texas (LT) (grade and stage) wound classification systems.

Research design and methods: Ulcer size, appearance, clinical evidence of infection, ischemia, and neuropathy at presentation were recorded, and patients were followed up until healing or for 6 months.

Results: Of 194 patients with new foot ulcers, 67.0% were neuropathic, 26.3% were neuroischemic, 1.0% were ischemic, and 5.7% had no identified underlying factors. Median (interquartile range [IQR]) ulcer size at presentation was 1.5 cm2 (0.6-4.0). Lower-limb amputations were performed for 15% of ulcers, whereas 65% healed [median (IQR) healing time 5 (3-10) weeks] and 16% were not healed at study termination; 4% of patients died. Wagner grade (P < 0.0001), and UT grade (P < 0.0001) and stage (P < 0.001) showed positive trends with increased number of amputations. For UT stage, the risk of amputation increased with infection both alone (odds ratio [OR] = 11.1, P < 0.0001) and in combination with ischemia (OR = 14.7, P < 0.0001), but not significantly with ischemia alone (OR = 4.6, P = 0.09). Healing times were not significantly different for each grade of the Wagner (P = 0.1) or the UT system (P = 0.07), but there was a significant stepwise increase in healing time with each stage of the UT system (P < 0.05), and stage predicted healing (P < 0.05).

Conclusions: Increasing stage, regardless of grade, is associated with increased risk of amputation and prolonged ulcer healing time. The UT system's inclusion of stage makes it a better predictor of outcome.