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...