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NIHR Signal Heel casts do not improve heel ulcers in diabetes

Published on 19 September 2017

doi: 10.3310/signal-000479

Fibreglass casts moulded to the heel did not improve heel ulcers in people with diabetes when added to usual ulcer care. Ulcers healed within six months in 44% of people using casts compared with 37% without which was not a statistically significant difference.

Foot ulcers are a common complication of diabetes, and heel ulcers are particularly difficult to treat. Based on the success of casts for treating ulcers elsewhere on the foot this trial was designed to test the effect and cost-effectiveness of using a similar approach for heel ulcers.

This NIHR-funded trial indicates that specially-moulded heel casts do not improve healing rates or pain, and were not a good use of NHS resources compared with usual care.

Uncertainty remains over the optimal approach for managing heel ulcers in people with diabetes.

  •   Diabetes, Musculo-skeletal disorders, Skin conditions, Acute and general medicine
Heel casts do not improve heel ulcers in diabetes

Why was this study needed?

Diabetes affects the blood circulation and nerves in the lower limbs which can lead to vascular or neuropathic ulcers. Around 15% of people with diabetes develop foot ulcers. Foot ulcers have a huge impact on people with diabetes and are expensive to treat, accounting for 0.7 to 0.8% of the UK NHS budget and about half die within five years.

Ulcers on the heel are particularly painful and difficult to treat and result in amputation in around 7% of cases. Standard treatment for ulcers elsewhere on the foot can involve a below-knee plaster cast to redistribute the person’s weight away from the site of the ulcer allowing it to heal. However, this hasn’t worked well for heel ulcers. With effective treatment lacking, many specialists have started to use lightweight, removable fibreglass heel casts.

This NIHR-funded trial assessed whether fibreglass heel casts improved outcomes compared with usual care.

What did this study do?

This randomised controlled trial recruited 509 adults with type 1 or 2 diabetes from 35 UK specialist foot services. Eligible participants had a grade 2-4 heel ulcer that had been present for at least two weeks and was 25mm2 or more in size.

Participants were allocated to an individually-moulded heel cast plus usual care or usual care alone. Ulcers were assessed fortnightly. If thought healed they were reassessed at two and four weeks by an assessor blind to randomisation to confirm. The main outcome was healing at or before 24 weeks.

Study drop-out was 16.5% but there were still sufficient participants to give confidence in the main analysis. Usual care varied across study centres, but this was thought to reflect normal practice.

What did it find?

  • By 24 weeks ulcers had healed in 44% of the heel cast group and 37% of the usual care group, which was not a statistically significant difference (odds ratio 1.42, 95% confidence interval [CI] 0.95 to 2.14).
  • Ulcers healed slightly faster in the heel cast group, but again this difference fell short of significance (adjusted hazards ratio 1.30, 95% CI 0.97 to 1.75). On the negative side, there was small suggestion that quality of ulcer healing was poorer in the heel cast group (7% of healed ulcers recurred within 18 weeks vs 4% with usual care) and that more people developed new ulcers on the opposite foot (17% vs 11%); neither of these results statistically significant.
  • There was no difference in ulcer-related pain or death between the groups.
  • Heel casts were not cost-effective. They cost an additional £67.41 per person, and usual care alone was assessed to be preferable when considering gains in quality-adjusted life years (QALYs). It was estimated that heel casts had less than a 5% chance of falling below the NHS willingness-to-pay threshold of £20,000 per QALY.

What does current guidance say on this issue?

NICE 2016 guidelines recommend treating foot ulcers  in people with diabetes by using one or more of the following: offloading using non-removable casts (for uninfected ulcers in the front and middle of the foot); treating any infection; cleaning out the wound (debridement); dressing the wound properly; or treating the poor circulation that worsens ulcers.

NICE recommend that people assessed to be at moderate-high risk of diabetic foot problems are given a pressure redistribution device to offload heel pressure. They should also be referred to the foot protection service.

What are the implications?

Evidence on the effectiveness of fibreglass heel casts has been lacking to date. This trial suggests they do not give meaningful benefit for people with heel ulcers and would not be a worthwhile addition to currently recommended foot ulcer care.

The study highlights a need to further investigate how to manage heel ulcers in people with diabetes in the UK.

Citation and Funding

Jeffcoate W, Game F, Turtle-Savage V, et al. Evaluation of the effectiveness and cost-effectiveness of lightweight fibreglass heel casts in the management of ulcers of the heel in diabetes: a randomised controlled trial. Health Technol Assess. 2017;21(34):1-92.

This project was funded by the National Institute for Health Research Health Technology Assessment programme (project number 09/01/53).

Bibliography

NICE. Diabetic foot problems: prevention and management. NG19. London: National Institute for Health and Care Excellence; 2016.

NICE. Pressure ulcers: prevention and management. CG179. London: National Institute for Health and Care Excellence; 2014.

Expert commentary

Heel ulcers are one of the most challenging ulcers to manage in foot clinics for people with diabetes. They take longer to heal and may persist for several months. At our centre, we routinely use heel casts in managing these ulcers with anecdotal good results. This study leaves one at the crossroads of whether one institutes a wholesale change in practice away from casts or one considers offering casts to a group where usual care fails to offer ulcer healing. I suspect there will be a middle course in favour of casts when we reach an impasse with chronic non-healing heel ulcers.

Dr Mujahid Saeed, Consultant Physician and Diabetologist, Queen Elizabeth Hospital Birmingham, University Hospital Birmingham NHS Foundation Trust; Honorary Senior Clinical Lecturer, University of Birmingham

Definitions

Ulcers were assessed using the National Pressure Ulcer Advisory Panel and European Pressure Ulcer Advisory Panel (NPUAP/EPUAP) scale.

  • Stage 1 indicates that a local area of skin (usually over a bony prominence) is reddened (-) but the skin is intact.
  • Stage 2 is a shallow open ulcer with a red/pink wound bed, or alternatively shiny blister, with no sloughing.
  • Stage 3 is full thickness skin loss where subcutaneous fat is visible and slough may be present.
  • Stage 4 is full thickness tissue loss, which can expose bone, tendon or muscles. A final stage is termed unstageable, where there is full thickness loss, the base is covered by slough and depth is unknown.