Are current wound classifications valid for predicting prognosis in people treated for limb-threatening diabetic foot ulcers?

Abstract

This study aims to investigate whether the current wound classifications were valid for the treatment prognosis of subjects treated for limb-threatening diabetic foot ulcers (LTDFU). A total of 1548 patients with LTDFU and infection were studied, with wounds recorded using the Wagner, Texas, PEDIS and WIfI classifications while major lower extremity amputations (LEAs) or in-hospital mortality incidences were defined as poor outcomes. Among them, 153 (9.9%) patients received major LEAs and 38 (2.5%) patients died. After adjustments, the Wagner classification and Texas stage as well as clinical factors such as comorbidity with major adverse cardiac events (MACE), being under dialysis and having serum levels of C-reactive protein (CRP) and albumin were independent factors for prognosis. For patients without dialysis, Wagner and Texas stage stood out independently for prognosis. For patients on dialysis, only levels of CRP (odds ratio [OR] = 2.2 in Wagner, OR = 2.0 in WIfI, OR = 2.2 in Texas, OR = 2.3 in PEDIS) and albumin (OR = 0.4 in four classifications) were valid predictors. The Wagner system and Texas stage were valid for predicting prognosis in treatment for LTDFUs, suggesting a role of vascular perfusion. MACE history, levels of CRP and albumin level should assist in prediction; more significantly, only levels of CRP and albumin appeared valid for those subjects undergoing dialysis.

Keywords: amputation; diabetic foot; limb salvage; prognosis; wound classification.

FIGURE 1

Multivariate logistic regression analysis for wound classifications and clinical factors associated with poor outcomes. Factors with statistical significance in Table 1 were selected for multivariate analysis. Apart from the Wagner classification, WIfI, Texas and PEDIS have lost their ability to predict prognosis. Major adverse cardiac events (MACE), dialysis and C‐reactive protein (CRP) were independent risk factors for poor outcomes in every classification, while serum albumin was significant in A, B and C classifications. BMI, body mass index; EVT, endovascular therapy; Hb, haemoglobin; UT, Univeristy of Texas wound classification system.

FIGURE 2

Risk factors associated with poor outcomes in subgroups of non‐dialysis and dialysis patients. The association of poor outcome with wound classifications and clinical factors was further tested in subgroup patients with or without dialysis. All factors listed were used for statistical adjustment. For dialysis patients, none of the four wound classifications was effective in predicting outcomes. C‐reactive protein (CRP) and albumin were more significant parameters in every wound classification (A–D). For non‐dialysis patients, both the Wagner and Texas stages were effective, while the Texas grade showed a trend but did not reach statistical significance. Patients (indicated as “♦”) who underwent major lower extremity amputation or mortality in the dialysis group were all classified as WIfI Stage 4. The odds ratio (OR) was 47 812 695.6 and the confidence interval (CI) could not be calculated. eGFR, estimated glomerular filtration rate; EVT, endovascular therapy; MACE, major adverse cardiac events.