A Comparison of Two Diabetic Foot Ulcer Classification Systems the Wagner and the University of Texas Wound Classification Systems
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Pathophysiology/Complications ORIGINAL ARTICLE A Comparison of Two Diabetic Foot Ulcer Classification Systems The Wagner and the University of Texas wound classification systems SAMSON O. OYIBO, MRCP HIENVU C. NGUYEN, DPM Foot ulcers will occur in 5–10% of the EDWARD B. JUDE, MD LAWRENCE B. HARKLESS, DPM diabetic population; up to 3% will have a IBRAHIM TARAWNEH, MD ANDREW J.M. BOULTON, MD lower-limb amputation (7). Ulceration is the most common precursor of amputation and has been identified as a component in more than two-thirds of lower-limb ampu- tations (8). The presence or absence of OBJECTIVE — In this study, the following two ulcer classification systems were applied to infection and/or ischemia, footwear and new foot ulcers to compare them as predictors of outcome: the Wagner (grade) and the Uni- pressure relief, and overall glycemic control versity of Texas (UT) (grade and stage) wound classification systems. influence the healing of ulcers (9). The depth of an ulcer is another important fac- RESEARCH DESIGN AND METHODS — Ulcer size, appearance, clinical evidence of tor that affects the outcome of diabetic foot infection, ischemia, and neuropathy at presentation were recorded, and patients were followed ulcers (10). Systematically recording these up until healing or for 6 months. confounding factors is critical to planning treatment strategies, monitoring treatment RESULTS — Of 194 patients with new foot ulcers, 67.0% were neuropathic, 26.3% were neu- effectiveness, predicting clinical outcomes, roischemic, 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 and improving communication among amputations were performed for 15% of ulcers, whereas 65% healed [median (IQR) healing health care providers (11). time 5 (3–10) weeks] and 16% were not healed at study termination; 4% of patients died. Wag- Various wound classification systems ner grade (P Ͻ 0.0001), and UT grade (P Ͻ 0.0001) and stage (P Ͻ 0.001) showed positive are used that attempt to encompass differ- trends with increased number of amputations. For UT stage, the risk of amputation increased ent characteristics of an ulcer (namely site, with infection both alone (odds ratio [OR] = 11.1, P Ͻ 0.0001) and in combination with depth, the presence of neuropathy, infec- ischemia (OR = 14.7, P Ͻ 0.0001), but not significantly with ischemia alone (OR = 4.6, P = tion, and ischemia, etc.) (12–18). It seems 0.09). Healing times were not significantly different for each grade of the Wagner (P = 0.1) or that poor clinical outcomes are generally the UT system (P = 0.07), but there was a significant stepwise increase in healing time with each Ͻ Ͻ associated with infection, peripheral vas- stage of the UT system (P 0.05), and stage predicted healing (P 0.05). cular disease, and increasing wound depth; CONCLUSIONS — Increasing stage, regardless of grade, is associated with increased risk it also appears that the progressive cumu- of amputation and prolonged ulcer healing time. The UT system’s inclusion of stage makes it lative effect of these comorbidities con- a better predictor of outcome. tributes to a greater likelihood of a diabetic foot ulcer leading to a lower-limb amputa- Diabetes Care 24:84–88, 2001 tion. An easy-to-use classification system that provides a uniform description of an ulcer (including depth and presence of infection and ischemia) (19) will help in planning treatment strategies and predict- eripheral neuropathy is a common the risk of ulceration induced by unper- ing outcomes in terms of healing and complication of diabetes, affecting ceived minor injury from shoes and other lower-limb amputations. PϾ30% of the diabetic population (1). physical trauma (3). The presence of macro- The well-established widely used Wag- In the foot, peripheral neuropathy leads to vascular disease, possibly functional micro- ner wound classification system (17) and dry skin and loss of the protective sensa- angiopathy (4,5), and infection increases the new University of Texas (UT) diabetic tions of pressure and pain; together with the probability of a foot ulcer leading to a wound classification system (18) both pro- reduced joint mobility (2), it also increases lower-limb amputation (6). vide descriptions of ulcers to varying degrees. Both wound classification systems are easy to use among health care providers, and both can provide a guide to planning From the Department of Medicine and Diabetes (S.O.O., E.B.J., I.T., A.J.M.B.), Manchester Royal Infirmary, Manchester, U.K.; and the Department of Orthopedics (H.C.N., L.B.H.), University of Texas Health Science treatment strategies. Center, San Antonio, Texas. The Wagner system assesses ulcer depth Address correspondence and reprint requests to Dr. Samson Oyibo, Department of Medicine, Manches- and the presence of osteomyelitis or gan- ter Royal Infirmary, Oxford Road, Manchester, M13 9WL, U.K. E-mail: samson@dc.cmht.nwest.nhs.uk. grene by using the following grades: grade 0 Received for publication 30 March 2000 and accepted in revised form 22 September 2000. Abbreviations: OR, odds ratio; UT, University of Texas; VPT, vibration perception threshold. (pre- or postulcerative lesion), grade 1 (par- A table elsewhere in this issue shows conventional and Système International (SI) units and conversion tial/full thickness ulcer), grade 2 (probing to factors for many substances. tendon or capsule), grade 3 (deep with 84 DIABETES CARE, VOLUME 24, NUMBER 1, JANUARY 2001 Oyibo and Associates Table 1—Baseline demography and foot ulcer characteristics in 194 patients clinical evidence of ischemia had noninva- sive ultrasound vascular studies and were seen by the vascular surgeon if necessary. Age (years) 56.6 ± 12.6 Patient follow-up was part of the normal Sex (M/F) 149/45 treatment. Unhealed ulcers were followed Diabetes (type 1/type 2) 21/173 up for a minimum period of 6 months. Duration of diabetes (years) 15.4 ± 9.9 2 Once a patient’s ulcer had healed completely Ulcer size (cm ) 1.48 (0.68–4.0) or a lower-limb amputation was performed, Type of ulcer (underlying factor) the outcome was noted and the patient was Neuropathic 130 (67.0) deemed to have completed the study. Neuroischemic 51 (26.3) Ischemic 2 (1) Statistical analysis Non-neuropathic, nonischemic* 11 (5.7) 2 2 A test for trend ( trend) was used to Site of ulcer† assess the trend association between Forefoot 151 (77.8) increasing grade or stage and the preva- Midfoot 23 (11.9) lence of lower-extremity amputation Hindfoot 20 (10.3) (25,25a). To assess the potential association Data are n, n (%), means ± SD, or median (interquartile range). *The mean age (47.6 vs. 57.1 years, P Ͻ 0.05) between stage and the number of amputa- and duration of diabetes (8.0 vs. 15.9 years, P Ͻ 0.01) of this group was much less than that of the rest of the group; †there were no differences in healing time or number of amputations among the different ulcer site groups tions performed by the end of the study 2 (P = 0.2). period, analysis with odds ratio (OR) was performed. Kaplan-Meier survival analysis was used to estimate median heal- osteitis), grade 4 (partial foot gangrene), and classification systems and staged using the ing times, and a log-rank test was used to grade 5 (whole foot gangrene). The UT sys- UT system. Ulcers were labeled infected if a compare healing times for different levels of tem assesses ulcer depth, the presence of purulent discharge was present with two grade or stage. Cox regression analysis was wound infection, and the presence of clini- other local signs (warmth, erythema, lym- used to assess the ability of grade and stage cal signs of lower-extremity ischemia. This phangitis, lymphadenopathy, oedema, to predict healing within the study period system uses a matrix of grade on the hori- pain). Wound depth was evaluated using a (25,25a). The 95% CI was calculated when- zontal axis and stage on the vertical axis. The sterile blunt probe. The ability to probe to ever appropriate, and statistical significance grades of the UT system are as follows: grade bone (20) with the presence of local or sys- was defined as a P value Ͻ0.05. Statistical 0 (pre- or postulcerative site that has healed), temic infection and suggestive radiological analysis was performed using SPSS for Win- grade 1 (superficial wound not involving features provided a clinical diagnosis of dows, version 9.0 (SPSS, Chicago). tendon, capsule, or bone), grade 2 (wound osteomyelitis. The diagnosis of lower- penetrating to tendon or capsule), and grade extremity vascular insufficiency was made RESULTS — A total of 194 diabetic 3 (wound penetrating bone or joint). Within clinically on the basis of absence of both patients with recently diagnosed diabetic each wound grade there are four stages: pedal pulses of the involved foot and/or an foot ulcers presented at the two specialist clean wounds (stage A), nonischemic ankle-brachial pressure index of Ͻ0.9 (21). diabetic foot centers. Table 1 shows the infected wounds (stage B), ischemic nonin- The presence of significant sensory neu- baseline demographic details for the group fected wounds (stage C), and ischemic ropathy was assessed using both the Bioth- of patients and baseline characteristics of infected wounds (stage D). esiometer (Biomedical Instruments, their foot ulcers at first presentation. The aim of this observational study Newbury, OH) (22), to measure vibration Eleven patients had no clinical evidence of was to determine which of the two wound perception threshold (VPT) at the tip of the moderate or severe neuropathy or vascular classification systems, the UT or the Wag- great toe, and the simplified Neuropathy ischemia; when compared with the rest of ner, is a better predictor of outcome.