Plantar pressures are higher in cases with diabetic foot ulcers compared to controls despite a longer stance phase duration

Table 3 Plantar pressure characteristics of the primary outcome measures by group

Outcome measure	DFU group (n = 21)	DMC group (n = 69)	HC group (n = 56)	Corrected P-value	Median difference DFU vs. DMC [95 % CI of difference]	Median difference DFU vs. HC [95 % CI of difference]	Cohen’s D DFU vs. DMC	Cohen’s D DFU vs. HC
Mean Peak plantar Pressure (mpp) N/cm²
Toes 2–5	3.0 [2.4–5.6]^a,b	2.5 [1.9–3.1]	2.1 [1.8–2.7]	P = 0.007	-0.8 [-1.5–(-)0.9]	-1.0 [-1.9–(-)0.5]	0.21	0.40
Metatarsal 1	5.7 [4.5–8.5]^b	5.5 [4.3–6.4]	4.6 [3.8–5.4]	P = 0.008	-	-1.5 [-2.7–(-)0.5]	-	0.36
Mid-foot	3.8 [3.1–6.5]^a,b	3.0 [2.5–3.7]	2.2 [1.8–2.9]	P < 0.001	-0.9 [-2.0–(-)0.3]	-1.7 [-3.0–(-)1.1]	0.32	0.63
Pressure-time integral (pti) Ns/cm²
Toes 2–5	0.9 [0.6–1.4]^a,b	0.6 [0.5–0.8]	0.5 [0.3–0.6]	P = 0.001	0.3 [0.1–0.6]	-0.4 [-0.8–(-)0.2]	0.45	0.60
Mid-foot	1.7 [1.2–2.5]^a,b	1.0 [0.8–1.3]	0.6 [0.4–0.9]	P = 0.001	0.6 [0.3–1.0]	-1.0 [-1.3–(-)-0.7]	0.67	1.07
Stance phase duration (ms)
	820 [752–960]^a,b	739 [699–788]	703 [669–748]	P < 0.001*	-84 [-140–(-)34]	-115 [-163–(-)66]	0.51	0.75

Data displays median and [IQR] values based on the ulcerated feet of the DFU group compared to the reported maximum values in the DMC and HC groups. Corrected p-values indicate p-values obtained after Holm correction rounded to 3 decimal places. Average stance phase duration indicates the average time the left and right feet were in contact with the ground in milliseconds (ms) from heel contact to toe-off. *Stance phase duration p-values were not corrected as this was analysed as an independent variable. All above reported plantar pressure outcome data were significant on post-hoc two-way tests and remained significant after adjusting for age, sex and BMI. Binary logistic regression analyses were only performed for variables which were significant on the post-hoc test. Cohen’s d was only calculated for variables which were significantly different after adjustment. (-) = not computed as this was not significantly different. See Additional file 1 for odds ratios and additional data. ^a=p < 0.05 when compared to the DMC group in post-hoc analysis ^b=p < 0.05 compared to the HC group in post hoc analysis

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