Vibrating Perception Threshold and Body Mass Index Are Associated with Abnormal Foot Plantar Pressure in Type 2 Diabetes Outpatients

Aims: This study investigated the influencing factors of foot plantar pressure and attempted to find practical indicators to predict abnormal foot pressure in patients with type 2 diabetes mellitus (T2DM). Subjects and Methods: Vibration perception threshold (VPT) and foot plantar pressure in 1,126 T2DM outpatients were examined. Patients were assigned to Group A (n=599), Group B (n=312), and Group C (n=215) according to VPT values and to Group I (n=555), Group II (n=436), and Group III (n=135) based on body mass index (BMI). The clinical characteristics and pressure–time integral (PTI) were compared among the three groups, and the associated factors of the total PTI in the entire foot (T-PTI) were analyzed. Results: PTI of Group C in heel medial and heel lateral was significantly higher than that of Group A (all P<0.01). PTI of Group B in the right fifth metatarsal and heel medial was significantly higher than that of Group A (all P<0.05). T-PTI of Group C was significantly higher than those of Groups A and B, and that of Group B was higher than that of Group A (all P<0.01). PTI of Groups II and III in the second, third, and fourth metatarsal, midfoot, heel medial, and heel lateral was significantly higher than that of Group I (all P<0.05). T-PTI of Groups II and III was significantly higher than that of Group I (all P<0.01). Pearson correlation analysis showed that T-PTI was positively associated with age, VPT, waist circumference, waist-to-hip ratio, and BMI (P<0.05). In multiple stepwise regression analysis, VPT (P=0.004) and BMI (P=0.000) were independent risk factors of T-PTI, and each 1 unit increase in BMI increased the T-PTI by 5.962 kPa•s. Receiver operator characteristic curve analysis further revealed that the optimal cutpoint of VPT and BMI to predict the abnormal PTI was 21 V (odds ratio=2.33, 95% confidence interval 1.67–3.25) and 24.9 kg/m2 (odds ratio=2.12, 95% confidence interval 1.55–2.90), respectively. Conclusions: Having a VPT higher than 21 V and a BMI above 24.9 kg/m2 increases the risk of excessive foot plantar pressure in Chinese T2DM.