Risk Factors for Plantar Foot Ulcer Recurrence in Neuropathic Diabetic Patients

Abstract

Recurrence of plantar foot ulcers is a common and major problem in diabetes but not well understood. Foot biomechanics and patient behavior may be important. The aim was to identify risk factors for ulcer recurrence and to establish targets for ulcer prevention. As part of a footwear trial, 171 neuropathic diabetic patients with a recently healed plantar foot ulcer and custom-made footwear were followed for 18 months or until ulceration. Demographic data, disease-related parameters, presence of minor lesions, barefoot and in-shoe plantar peak pressures, footwear adherence, and daily stride count were entered in a multivariate multilevel logistic regression model of plantar foot ulcer recurrence. A total of 71 patients had a recurrent ulcer. Significant independent predictors were presence of minor lesions (odds ratio 9.06 [95% CI 2.98-27.57]), day-to-day variation in stride count (0.93 [0.89-0.99]), and cumulative duration of past foot ulcers (1.03 [1.00-1.06]). Significant independent predictors for those 41 recurrences suggested to be the result of unrecognized repetitive trauma were presence of minor lesions (10.95 [5.01-23.96]), in-shoe peak pressure <200 kPa with footwear adherence >80% (0.43 [0.20-0.94]), barefoot peak pressure (1.11 [1.00-1.22]), and day-to-day variation in stride count (0.91 [0.86-0.96]). The presence of a minor lesion was clearly the strongest predictor, while recommended use of adequately offloading footwear was a strong protector against ulcer recurrence from unrecognized repetitive trauma. These outcomes define clear targets for diabetic foot screening and ulcer prevention.