SLR - October 2016 - Lisa D. Breshears

Role of Determinants of Adherence to Off-Loading in Diabetic Foot Ulcer Healing: A Prospective Investigation

Reference: Crews RT, Shen BJ, Campbell L, Lamont PJ, Boulton AJ, Peyrot M, Kirsner RS, Vileikyte L. Role and Determinants of Adherence to Off-loading in Diabetic Foot Ulcer Healing: A Prospective Investigation. Diabetes Care. 2016 Aug;39(8): 1371–1377.

Scientific Literature Review

Reviewed By: Lisa D. Breshears, DPM
Residency Program: Chino Valley Medical Center

Podiatric Relevance: The purpose of the study was to determine the association between off-loading adherence and its correlation with diabetic ulcer healing within six weeks of treatment. The authors hypothesized that higher levels of off-loading adherence would be associated with smaller ulcer size. A secondary hypothesis that physical and psychological factors would influence off-loading adherence was also presented.  

Methods: This was a prospective, multicenter and international study, which included 79 patients with type 2 diabetes and a diabetic foot ulcer on a weightbearing surface. All patients received routine, sharp debridement of the ulcers and were instructed to wear an offloading device when weightbearing. Each patient had a concealed activity monitor in the offloading device, and each patient was dispensed a secondary activity monitor to be worn on their hips. Diabetic foot ulcers were photographed and measured by planimetric wound area weekly. Self-report psychological measures were obtained by using the Neuropathy and Foot Ulcer Quality of Life scale (NeuroQoL), the Revised Illness Perception Questionnaire (IPQ-R) and the Hospital Anxiety and Depression Scale (HADS).   

Results: The subjects were predominantly white males in their mid-50s who had poor glycemic control and severe peripheral neuropathy. Most of the ulcers were superficial and noninfected. At the six-week follow-up, there was a significant reduction in the ulcer size and 24 percent of the patients had wound closure. The subjects were found to be actively moving 6.7 ± 3.8 hours per day, but they only wore their offloading devices during 59 percent ± 22 percent of the time. Smaller initial ulcer size, location and better offloading adherence significantly predicted smaller ulcer sizes at six weeks. Larger ulcers, more severe neuropathy and greater postural instability significantly predicted poor off-loading adherence.  

Conclusion:
According to the authors, this is the first study to objectively associate off-loading adherence to diabetic ulcer healing. Postural instability was a symptom that was strongly associated with poor off-loading adherence possibly due to biomechanical challenges when wearing an offloading device. Predictors of offloading adherence were more severe neuropathy and larger, and more severe ulcers. They also determined that there was no significant association of adherence with depression. Patients were ambulating without their offloading devices approximately 59 percent of the time. Another confounding factor was that the activity monitors did not assess periods when patients do not wear their activity monitors and their offloading device or periods of standing. Practitioners must take into account that patients may not wear their offloading devices for the majority of the time, and they may choose not to do so due to balance and stability issues. It may be beneficial to consider other offloading methods or to implement safety precautions to prevent falls.  

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