Healing a diabetic foot ulcer (DFU) can be quite challenging in and of itself, but how do you prevent recurrence? On one hand, increased mobility and exercise would be beneficial for patients with diabetes, but how does one achieve an optimal level of increased activity when there is a reported DFU recurrence rate of nearly 40 percent within a year of healing a DFU?1
With this in mind, Fernando and colleagues recently published a position statement with recommendations on how to transition this high-risk population back into footwear and resumption of activity.2 The multidisciplinary panel of authors suggests that the combination of gradual monitored activity training along with daily monitoring of skin temperature may have an impact in mitigating DFU recurrence.
Bijan Najafi, PhD, MSc, a co-author of the study, says there are key benefits to simultaneous monitoring of both physical activities (e.g., step count and duration of standing) and plantar temperature with technologies such as smart socks. These simultaneous measurements enable one to assess thermal stress response or the change in plantar temperature in response to repetitive stress, according to Dr. Najafi.
“In previous studies, we demonstrated that thermal stress response is helpful to measure some of the key risk factors associated with ulcer recurrence including shear force and vascular health.3,4 In addition, thermal stress response may better identify acute Charcot foot,” notes Dr. Najafi, the Director of Clinical Research and a Professor of Surgery with the Division of Vascular Surgery and Endovascular Therapy at the Baylor College of Medicine.5
“We have to understand that the activity/inflammation/re-ulceration equation is different for each patient,” says David G. Armstrong, DPM, MD, PhD, the President of the American Limb Preservation Society. “That is why we like to use thermometry to help identify potentially dangerous, pre-ulcerative ‘hot spots.’”
Dr. Najafi says another important benefit is determining the acceptable dosage of physical activity after a patient has healed a DFU.
“In our recent study, we demonstrated that physical activity is significantly reduced when the patient has an active ulcer compared to pre-ulceration but gradually returned to pre-ulceration physical activity after healing an ulcer,” points out Dr. Najafi.2 “We anticipate that a sudden increase in the level of physical activities after a healed ulcer could increase the risk of ulcer recurrence. Thus, to safely increase the level of physical activity after a healed ulcer, we recommend checking skin temperature. In the case of identifying a plantar hot spot, we may advise the patient to reduce his or her level of activities to prevent ulcer recurrence.”
Dr. Najafi concedes this hypothesis still needs to be validated in future studies. That said, he believes the combination of monitored activity dosing and skin temperature has promise not only for those with healed DFUs but for patients who have had partial foot amputations or reconstructive foot surgery as well.
“In my personal opinion, I believe gradual activity dosing strategies could help (people with) all these conditions as we want to avoid too much stress after a foot surgery or a healed ulcer while helping them return to the same level of physical activities before surgery or ulcer,” explains Dr. Najafi.
Dr. Armstrong concurs.
“(In the position statement), we discuss the notion that every patient is his or her own control, and thanks to newer, more accurate and ubiquitous/inexpensive activity monitors, patients can identify their ideal activity dose,” maintains Dr. Armstrong, a Professor of Surgery at the Keck School of Medicine at the University of Southern California.2
Could emerging technologies in remote patient monitoring, in regard to activity and skin temperature, help improve patient education and engagement? Drs. Armstrong and Najafi have seen some preliminary evidence of this.
“Remote measurement of plantar pressure and timely notification about high pressure using a smartwatch has shown effectiveness in increasing patient adherence to wearing prescribed footwear and educating the patient to avoid risky physical activity behavior such as prolonged unbroken standing longer than 15 minutes,” points out Dr. Najafi.6
“I anticipate that timely and comprehensive notification about an abnormal plantar temperature and guidance on optimizing the level of physical activity accordingly could help personalize care for people with diabetic foot problems, including encouraging them to be active while protecting their feet,” says Dr. Najafi. He cautions, however, that this notion remains speculative as he is not aware of any clinical study testing this concept at this time.
In reviewing the literature for the position statement, Dr. Najafi says he was surprised by the lack of level 1 evidence studies testing the association between physical activity dosing and the risk of ulcer recurrence as well as the lack of studies attempting to managing activity dose to facilitate a safe recovery after a healed ulcer.
In regard to future studies of the DFU remission period, Dr. Armstrong says he would like to see more data supporting individualized “activity profiles and phenotypes.” Dr. Najafi concurs.
“With advances in wearable technologies and remote patient monitoring, I am hoping to see more studies in the area of personalized medicine applications to prevent ulcer recurrence via objective and remote measurement of foot risk factors,” adds Dr. Najafi.
References
- Armstrong DG, Boulton AJM, Bus SA. Diabetic foot ulcers and their recurrence. N Engl J Med. 2017;376(24):2367-2375.
- Fernando ME, Woelfel SL, Perry D, et al. Dosing activity and returning to pre-ulcer function in diabetic foot remission: patient recommendations and guidance from the Limb Preservation Consortium at USC and the National Rehabilitation Center at Rancho Los Amigos. J Am Podiatr Med Assoc. 2021;Mar 29;20-166. doi: 10.7547/20-166. Online ahead of print.
- Rahemi H, Armstrong DG, Enriquez A, Owl J, Talal TK, Najafi B. Lace up for healthy feet: the impact of shoe closure on plantar stress response. J Diabetes Sci Technol. 2017;11(4):678-684.
- Wrobel JS, Ammanath P, Le T, et al. A novel shear reduction insole effect on the thermal response to walking stress, balance, and gait. J Diabetes Sci Technol. 2014;8(6):1151-6.
- Najafi B, Wrobel JS, Grewal G, et al. Plantar temperature response to walking in diabetes with and without acute Charcot: the Charcot activity response test. J Aging Res. 2012;2012:140968. doi: 10:1155/2012/140968.
- Najafi B, Mohseni H, Grewal GS, Talal TK, Menzies RA, Armstrong DG. An optical-fiber-based smart textile (smart socks) to manage biomechanical risk factors associated with diabetic foot amputation. J Diabetes Sci Technol. 2017;11(4):668-677.