By Larry Hand
Postural instability in patients with diabetic foot ulcers is a strong predictor of poor adherence to off-loading treatment with removable devices, according to a new multicenter study in which off-loading adherence was, in turn, a strong predictor of wound healing.
“The off-loading devices would amplify the instability—hence the tendency to decrease adherence,” first author Ryan T. Crews, MS, clinical research scientist and operations manager at Rosalind Franklin University’s Center for Lower Extremity Ambulatory Research in North Chicago, IL, told LER by email.
In the same study, epublished in June by Diabetes Care, researchers found that more severe ulcer at baseline, more severe neuropathy, and greater self-reported foot pain were associated with better adherence to treatment.
“In this case, more severe wounds were associated with greater adherence, which likely suggests that as patients became more concerned about the gravity of the situation, they became more compliant,” Crews added.
Crews and colleagues prospectively assessed 79 patients with type 2 diabetes and plantar diabetic foot ulcers—46 in the UK and 33 in the US—who wore removable off-loading devices for six weeks.
They collected patient-reported data at baseline, then followed a standardized foot ulcer management protocol involving regular, sharp surgical wound debridement, dressings, and off-loading ulcers. Ulcers were examined and photographed weekly.
They used a removable cast walker (RCW) as a default off-loading device, but clinicians were allowed to use other removable devices. Sixty-one of the 79 participants used a RCW. The researchers assessed off-loading adherence using a concealed activity monitor in the device and by asking participants to attach a second monitor to their hips during activity.
Overall, the group experienced a substantial reduction in mean wound size, from 230 mm2 to 109 mm2. Nineteen (24%) participants achieved complete wound closure by the six-week visit. Patients averaged 6.7 hours a day of active movement and wore their off-loading devices 59% of that time.
Better off-loading adherence was a predictor of decreased ulcer size by six weeks, as were smaller baseline ulcer size and UK location. There were no significant associations between off-loading adherence and ulcer-specific beliefs and emotional responses at baseline.
The researchers did not compare adherence differences between more stable and less stable patients. And they did not discuss design features of the RCW devices that may have contributed to postural instability specifically or adherence in general.
“We’re presently researching design features that will make them more amenable to patients,” Crews said.
The postural stability finding makes sense, Jaap van Netten, PhD, scientific director at Diabetic Foot Australia in Queensland, told LER by email.
“Postural instability is enhanced when using a [cumbersome] device, so it is not surprising that adherence is lower in this group of patients, as they will experience more problems while wearing the device,” van Netten said.
The study also underscores the complexity of patient adherence, which is important for clinicians to understand, he noted.
“Patients need to be motivated to adhere to the device,” van Netten continued. “However, improving acceptance and motivation, and better communication, may all take some time in the early phases of treatment. Unfortunately, we see all too often that clinics are so packed that this time is not available, even though this results in more time being spent in the long run. One way to improve adherence might be a greater investment in increasing patients’ acceptance and motivation via person-centered communication early in treatment.”
van Netten and colleagues described two patient-centered communication techniques to improve adherence to therapeutic footwear in an article epublished in June by Prosthetics & Orthotics International.
Crews RT, Shen B-J, Campbell L, et al. Role and determinants of adherence to off-loading in diabetic foot ulcer healing: a prospective investigation. Diabetes Care 2016 June 6. [Epub ahead of print]
van Netten JJ, Francis A, Morphet A, et al. Communication techniques for improved acceptance and adherence with therapeutic footwear. Prosthet Orthot Int 2016 June 8. [Epub ahead of print]