A new application of the Rotterdam Diabetic Foot Study Test Battery: grading pedal sensory loss to predict the risk of foot ulceration

Abstract

Aims: To assess the relationship between the degree of loss of foot sensation at baseline and incidence of foot ulceration (DFU). Methods: Diabetic patients (n = 416) participating in the observational Rotterdam Diabetic Foot (RDF) Study were followed prospectively (median 955.5 days (IQR, 841.5–1121)). Subjects underwent sensory testing of the feet (39-item RDF Study Test Battery) at baseline and were assessed regarding incident DFU. Seven groups of incremental degree of sensory loss were distinguished, according to the RDF-39 sum score. Kaplan-Meier and regression analyses were used to determine the independent hazard of baseline variables for new DFU. Results: 40 participants developed DFUs. The mean incident rate of new-onset ulceration from study start was 4.5 (95%CI: 3.3 to 6.1) per 100 person-years, which increased significantly from 0 to 67.70 in the seven groups (p < 0.0005). Predictors for DFUs were higher RDF-39 score (aHR: 1.173, p < 0.0005) and kidney function (aHR: 1.022, p = 0.016). Prior DFU suggests increased mortality risk. Conclusions: The degree of sensory loss at baseline was associated with progression to DFU during follow-up. Grading the loss of sensation using the RDF Study Test Battery may result in a more precise risk stratification compared to the use of the 10 g monofilament according to current guidelines.