Plantar pressure as a risk assessment tool for diabetic foot ulceration in egyptian patients with diabetes

Abstract

Background: Diabetic foot ulceration is a preventable long-term complication of diabetes. In the present study, peak plantar pressures (PPP) and other characteristics were assessed in a group of 100 Egyptian patients with diabetes with or without neuropathy and foot ulcers. The aim was to study the relationship between plantar pressure (PP) and neuropathy with or without ulceration and trying to clarify the utility of pedobarography as an ulceration risk assessment tool in patients with diabetes.

Subjects and methods: A total of 100 patients having diabetes were selected. All patients had a comprehensive foot evaluation, including assessment for neuropathy using modified neuropathy disability score (MNDS), for peripheral vascular disease using ankle brachial index, and for dynamic foot pressures using the MAT system (Tekscan). The studied patients were grouped into: (1) diabetic control group (DC), which included 37 patients who had diabetes without neuropathy or ulceration and MNDS ≤2; (2) diabetic neuropathy group (DN), which included 33 patients who had diabetes with neuropathy and MNDS >2, without current or a history of ulceration; and (3) diabetic ulcer group (DU), which included 30 patients who had diabetes and current ulceration, seven of those patients also gave a history of ulceration.

Results: PP parameters were significantly different between the studied groups, namely, forefoot peak plantar pressure (FFPPP), rearfoot peak plantar pressure (RFPPP), forefoot/rearfoot ratio (F/R), forefoot peak pressure gradient (FFPPG) rearfoot peak pressure gradient (RFPPG), and forefoot peak pressure gradient/rearfoot peak pressure gradient (FFPPG/RFPPG) (P < 0.05). FFPPP and F/R were significantly higher in the DU group compared to the DN and DC groups (P < 0.05), with no significant difference between DN and DC. FFPPG was significantly higher in the DU and DN groups compared to the DC group (P < 0.05). RFPPP and FFPPG/RFPPG were significantly higher in the DU and DN groups compared to the DC group (P < 0.05) with no significant difference between the DN and DU groups (P > 0.05). FFPPP, F/R ratio, FFPPG, and FFPPG/RFPPG correlated significantly with the severity of neuropathy according to MNDS (P < 0.05). These same variables as well as MNDS were also significantly higher in patients with foot deformity compared to those without deformity (P < 0.05). Using the receiver operating characteristic analysis, the optimal cut-point of PPP for ulceration risk, as determined by a balance of sensitivity, specificity, and accuracy was 335 kPa and was found at the forefoot. Multivariate logistical regression analysis for ulceration risk was statistically significant for duration of diabetes (odds ratio [OR] = 0.8), smoking (OR = 9.7), foot deformity (OR = 8.7), MNDS (OR = 1.5), 2-h postprandial plasma glucose (2 h-PPG) (OR = 0.9), glycated hemoglobin (HbA1c) (OR = 2.1), FFPPP (OR = 1.0), and FFPPG (OR = 1.0).

Conclusion: In conclusion, persons with diabetes having neuropathy and/or ulcers have elevated PPP. Risk of ulceration was highly associated with duration of diabetes, smoking, severity of neuropathy, glycemic control, and high PP variables especially the FFPPP, F/R, and FFPPG. We suggest a cut-point of 355 kPa for FFPPP to denote high risk for ulceration that would be more valid when used in conjunction with other contributory risk factors, namely, duration of diabetes, smoking, glycemic load, foot deformity, and severity of neuropathy.

Keywords: diabetic foot ulceration; diabetic neuropathy; pedobarography; plantar pressure.

Figure 1

Receiver operating characteristic analysis (ROC) as regards RFPPP.