Validation of a diabetic wound classification system. The contribution of depth, infection, and ischemia to risk of amputation.

Abstract

To validate a wound classification instrument that includes assessment of depth, infection, and ischemia based on the eventual outcome of the wound. We evaluated the medical records of 360 diabetic patients presenting for care of foot wounds at a multidisciplinary tertiary care foot clinic. As per protocol, all patients had a standardized evaluation to assess wound depth, sensory neuropathy, vascular insufficiency, and infection. Patients were assessed at 6 months after their initial evaluation to see whether an amputation had been performed. There was a significant overall trend toward increased prevalence of amputations as wounds increased in both depth (chi 2trend = 143.1, P < 0.001) and stage (chi 2trend = 91.0, P < 0.001). This was true for every subcategory as well with the exception of noninfected, nonischemic ulcers. There were no amputations performed within this stage during the follow-up period. Patients were more than 11 times more likely to receive a midfoot or higher level amputation if their wound probed to bone (18.3 vs. 2.0%, P < 0.001, chi 2 = 31.5, odds ratio (OR) = 11.1, CI = 4.0-30.3). Patients with infection and ischemia were nearly 90 times more likely to receive a midfoot or higher amputation compared with patients in less advanced wound stages (76.5 vs. 3.5%, P < 0.001, chi 2 = 133.5, OR = 89.6, CI = 25-316). Outcomes deteriorated with increasing grade and stage of wounds when measured using the University of Texas Wound Classification System.