Independent Observational Analysis of Ulcer Outcomes for SINBAD and University of Texas Ulcer Scoring Systems

Abstract

OBJECTIVE The aim of this study was to compare the University of Texas (UT) and Site, Ischemia, Neuropathy, Bacterial Infection, and Depth (SINBAD) foot ulcer scores in predicting ulcer outcome within a routine diabetes foot clinic. RESEARCH DESIGN AND METHODS From 2006 to 2018, data were collected from all patients attending an outpatient diabetes foot clinic with an active ulcer not healed within 4 weeks. UT and SINBAD were compared in predicting ulcer outcome. A unified numerical score for UT was constructed and compared with UT grade (depth) and stage scores. Outcomes included death, a healed ulcer, or a nonhealed ulcer, which included major or minor amputation and nonhealing chronic ulcers. RESULTS Outcomes were available from 1,645 ulcer outcomes in 1,068 patients (mean [SD] age 65.4 [4] years, 72% male), of which 1,108 (67%) healed. With exclusion of death as an adverse outcome, the c-statistic (area under operator curve) was 0.67 (95% CI 0.65–0.71) for UT grade/depth and 0.64 (0.61–0.67) for UT stage. The new unified UT score had an improved c-statistic of 0.71 (0.68–0.74). The c-statistic was 0.72 (0.69–0.75) for SINBAD. There was a stepwise decrease in the proportion of ulcers healed for each increased score on ulcer grading for both grading schemes. CONCLUSIONS This large and independent observational comparison, in a real-world clinical setting, demonstrated that the UT and SINBAD diabetes foot ulcer grading schemes had similar prognostic ability for predicting foot ulcer outcomes. We have devised and validated a unified numerical scoring system for UT.