Site-Specific, Critical Threshold Barefoot Peak Plantar Pressure Associated with Diabetic Foot Ulcer History: A Novel Approach to Determine DFU Risk in the Clinical Setting

• Published in: Medicina (Kaunas, Lithuania) Lithuania), 2022-01, Vol.58 (2), p.166
• Main Authors: Abbott, Caroline A, Chatwin, Katie E, Rajbhandari, Satyan M, John, Kanwal M, Pabbineedi, Sushma, Bowling, Frank L, Boulton, Andrew J M, Reeves, Neil D
• Format: Article
• Language: English
• Subjects: Amputation; Calibration; Carbon footprint; critical threshold; Cross-Sectional Studies; Diabetes; Diabetes Mellitus; Diabetic Foot - epidemiology; Foot; Foot diseases; foot ulcer; Gait; Humans; Leg ulcers; Medical research; peak plantar pressure; Pressure; pressure measurement device; PressureStat; Toes; Walking
• ISSN: 1648-9144; 1010-660X; 1648-9144
• DOI: 10.3390/medicina58020166

Barefoot peak plantar pressures (PPPs) are elevated in diabetes patients with neuropathic foot ulcer (DFU) history; however, there is limited reported evidence for a causative link between high barefoot PPP and DFU risk. We aimed to determine, using a simple mat-based methodology, the site-specific, barefoot PPP critical threshold that will identify a plantar site with a previous DFU. In a cross-sectional study, barefoot, site-specific PPPs were measured with normal gait for patients with DFU history ( = 21) and healthy controls ( = 12), using a validated carbon footprint system. For each participant, PPP was recorded at twelve distinct plantar sites (1st-5th toes, 1st-5th metatarsal heads (MTHs), midfoot and heel), per right and left foot, resulting in the analysis of = 504 distinct plantar sites in the diabetes group, and = 288 sites in the control group. Receiver operator characteristic curve analysis determined the optimal critical threshold for sites with DFU history. Median PPPs for the groups were: diabetes sites with DFU history ( = 32) = 5.0 (3.25-7.5) kg/cm , diabetes sites without DFU history ( = 472) = 3.25 (2.0-5.0) kg/cm , control sites ( = 288) = 2.0 (2.0-3.25) kg/cm ; ( < 0.0001). Diabetes sites with elevated PPP (>6 kg/cm ) were six times more likely to have had DFU than diabetes sites with PPP ≤ 6 kg/cm (OR = 6.4 (2.8-14.6, 95% CI), < 0.0001). PPP > 4.1 kg/cm was determined as the optimal critical threshold for identifying DFU at a specific plantar site, with sensitivity/specificity = 100%/79% at midfoot; 80%/65% at 5th metatarsal head; 73%/62% at combined midfoot/metatarsal head areas. We have demonstrated, for the first time, a strong, site-specific relationship between elevated barefoot PPP and previous DFU. We have determined a critical, highly-sensitive, barefoot PPP threshold value of >4.1 kg/cm , which may be easily used to identify sites of previous DFU occurrence and, therefore, increased risk of re-ulceration. This site-specific approach may have implications for how high PPPs should be investigated in future trials.