Certain foot deformities, reduced skin oxygenation and foot perfusion, poor vision, greater body mass, and both sensory and autonomic neuropathy independently influence foot ulcer risk, thereby providing support for a multifactorial etiology for diabetic foot ulceration.

OBJECTIVE -The ability of readily available clinical information to predict the occurrence of diabetic foot ulcer has not been extensively studied. We conducted a prospective study of the individual and combined effects of commonly available clinical information in the prediction of diabetic foot ulcer occurrence.RESEARCH DESIGN AND METHODS -We followed 1,285 diabetic veterans without foot ulcer for this outcome with annual clinical evaluations and quarterly mailed questionnaires to identify foot problems. At baseline we assessed age; race; weight; current smoking; diabetes duration and treatment; HbA 1c (A1C); visual acuity; history of laser photocoagulation treatment, foot ulcer, and amputation; foot shape; claudication; foot insensitivity to the 10-g monofilament; foot callus; pedal edema; hallux limitus; tinea pedis; and onychomycosis. Cox proportional hazards modeling was used with backwards stepwise elimination to develop a prediction model for the first foot ulcer occurrence after the baseline examination.RESULTS -At baseline, subjects were 62.4 years of age on average and 98% male. Mean follow-up duration was 3.38 years, during which time 216 foot ulcers occurred, for an incidence of 5.0/100 person-years. Significant predictors (P Յ 0.05) of foot ulcer in the final model (hazard ratio, 95% CI) included A1C (1.10, 1.06 -1.15), impaired vision (1.48, 1.00 -2.18), prior foot ulcer (2.18, 1.61-2.95), prior amputation (2.57, 1.60 -4.12), monofilament insensitivity (2.03, 1.50 -2.76), tinea pedis (0.73, 0.54 -0.98), and onychomycosis (1.58, 1.16 -2.16). Area under the receiver operating characteristic curve was 0.81 at 1 year and 0.76 at 5 years.CONCLUSIONS -Readily available clinical information has substantial predictive power for the development of diabetic foot ulcer and may help in accurately targeting persons at high risk of this outcome for preventive interventions. Diabetes Care 29:1202-1207, 2006D iabetic foot ulcer and amputation continue to cause considerable morbidity among persons with diabetes (1). Foot ulcer has been recognized as an important antecedent of lower extremity amputation in multiple studies (2,3). Progress has occurred in understanding the pathogenesis of these complications (4), and methods to assist in the prediction of these outcomes have also been developed using various modalities, including lower limb sensory testing (5), thermography (6), and assessment of peak plantar pressure (7). Some of these modalities are unavailable to the vast majority of primary care clinical practitioners who provide much of the preventive and acute care of persons with diabetes.Also, the use of multiple risk indicators in combination to assist in the future prediction of diabetes complications has not been thoroughly explored and reported in a manner that permits assessment of prediction accuracy.Given the need for a prediction model of diabetic foot ulcer that utilizes multiple risk indicators that would be available in all clinical encounters that take place between patients and primary care or n...

This prospective study shows that peripheral sensory neuropathy, PVD, foot ulcers (particularly if they appear on the same side as the eventual LEA), former amputation, and treatment with insulin are independent risk factors for LEA in patients with diabetes.

Both neuropathy and vasculopathy are strong independent risk factors for the development of diabetic foot ulcers. In our model, the strongest risk factor is impaired cutaneous oxygenation. However, in the clinical setting, sensory examination with a 5.07 monofilament probably remains the single most practical measure of risk assessment.

Poorer glycemic control increases the risk of neuropathy and is amenable to intervention. Height and age directly increase risk of neuropathy and may help identify patients at risk. A proportion of neuropathy in diabetic veterans is probably due to or worsened by alcohol ingestion. Neuropathy was less common in current smokers than subjects not currently smoking.

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The natural history of tissue repair and the critical determinants of faulty healing of diabetic ulcers remain obscure despite recent advances in our knowledge of the cellular physiology of normal cutaneous healing. To characterize the chronology and identify important factors affecting healing, we applied an objective method to quantify the rate of wound healing of full-thickness lower-extremity ulcers in 46 diabetic outpatients who received local wound care under a standardized clinical protocol. The initial ulcer healing rate, eventual status of tissue repair, and definitive clinical outcome were not significantly associated with age; diabetes type, duration, or treatment; level or change in glycosylated hemoglobin; current smoking; presence of sensory neuropathy; ulcer location or class; initial infection; or frequency of recurrent infections. However, direct measures of local cutaneous perfusion, estimated by periwound measurements of transcutaneous O2 tension (TcPo2) and transcutaneous CO2 tension (TcPco2), were significantly associated with the initial rate of tissue repair (P = 0.003 and 0.005, respectively). The strong prediction of early healing by these parameters of local skin perfusion was independent from the effects of segmental Doppler arterial blood pressure at the dorsalis pedis, although eventual ulcer reepithelialization was significantly related to foot blood pressure and periwound TcPo2 and TcPco2. We conclude that periwound cutaneous perfusion is the critical physiological determinant of diabetic ulcer healing, indicating a 39-fold increased risk of early healing failure when the average periwound TcPo2 is less than 20 mmHg.

Arterial disease and neuropathy emerged as the only limb-specific risk factors for amputation, but these and several person-level factors may be amenable to prevention or treatment interventions to potentially reduce diabetic amputation risk.