Screening techniques to identify people at high risk for diabetic foot ulceration: a prospective multicenter trial

Diabetic foot ulceration is a preventable long-term complication of diabetes. A multicenter prospective follow-up study was conducted to determine which risk factors in foot screening have a high association with the development of foot ulceration.

A total of 248 patients from 3 large diabetic foot centers were enrolled in a prospective study. Neuropathy symptom score, neuropathy disability score (NDS), vibration perception threshold (VPT), Semmes-Weinstein monofilaments (SWFs), joint mobility, peak plantar foot pressures, and vascular status were evaluated in all patients at the beginning of the study. Patients were followed-up every 6 months for a mean period of 30 months (range 6-40), and all new foot ulcers were recorded. The sensitivity, specificity, and positive predictive value of each risk factor were evaluated.

Foot ulcers developed in 95 feet (19%) or 73 patients (29%) during the study. Patients who developed foot ulcers were more frequently men, had diabetes for a longer duration, had nonpalpable pedal pulses, had reduced joint mobility, had a high NDS, had a high VPT, and had an inability to feel a 5.07 SWE NDS alone had the best sensitivity, whereas the combination of the NDS and the inability to feel a 5.07 SWF reached a sensitivity of 99%. On the other hand, the best specificity for a single factor was offered by foot pressures, and the best combination was that of NDS and foot pressures. Univariate logistical regression analysis yielded a statistically significant odds ratio (OR) for sex, race, duration of diabetes, palpable pulses, history of foot ulceration, high NDSs, high VPTs, high SWFs, and high foot pressures. In addition, 94 (99%) of the 95 ulcerated feet had a high NDS and/or SWF which resulted in the highest OR of 26.2 (95% CI 3.6-190). Furthermore, in multivariate logistical regression analysis, the only significant factors were high NDSs, VPTs, SWFs, and foot pressures.

Clinical examination and a 5.07 SWF test are the two most sensitive tests in identifying patients at risk for foot ulceration, especially when the tests are used in conjunction with each other. VPT measurements are also helpful and can be used as an alternative. Finally, foot pressure measurements offer a substantially higher specificity and can be used as a postscreening test in conjunction with providing appropriate footwear.