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A simple tool predicted the risk of foot ulcers in people with diabetes. The decision support tool combined 3 pieces of information from standard tests and research found it was easy to use. The tool could help ensure that preventive treatments are offered to those most at risk.

Ulcers are open wounds. In diabetes, foot ulcers are such a common complication that they account for almost 1% of the total NHS budget. Foot ulcers can lead to amputations and premature death, but can be prevented. However, it is difficult to identify the people most at risk. UK guidance currently recommends using 8 to 10 tests to look for signs of nerve damage or infection, and assess the risk of an ulcer.

In this study, researchers tested a tool based on only 3 pieces of information: insensitivity, a pulse in the foot, and previous ulcers or amputation. This information is routinely collected from people with diabetes. The research team found the tool could identify people at risk of developing ulcers.

The researchers hope it will simplify foot care for people with diabetes, and reduce the number of foot ulcers. This could improve the health and quality of life of people with diabetes, and save money for the NHS. It has been estimated that the NHS could save £250 million per year if the number of foot ulcers was reduced by one-third.

Further information on diabetic foot ulcers is available on the NHS website.

What’s the issue?

People with diabetes are more likely than others to develop foot ulcers, but many are unaware of their risk. A Diabetes UK survey in 2017 showed that 1 in 3 people with diabetes did not know that foot ulcers are a serious complication of their condition. Foot ulcers can lead to foot and leg amputations, and to early death. Amputations relating to diabetes are increasing in young and middle-aged adults in the UK.

Prevention of ulcers can involve careful monitoring a person’s feet, using a special thermometer (dermal infrared thermomenter) to find areas of the foot with a higher temperature. This could indicate that an ulcer might develop. People may be advised to keep off their feet until this resolves, and often need custom-made shoes or insoles.

However, some existing tools to predict the risk of foot ulcers are not supported by strong evidence, and can be complex. Guidance from the National Institute for Health and Care Excellence (NICE) recommends collecting 8 to 10 pieces of information. This includes previous foot examinations for signs of infection or gangrene. No current model gives a detailed risk score; instead, they report that someone is low risk, high risk or recommend they are referred to a foot clinic.

Researchers wanted to create a tool that could give people with diabetes a score of their own risk of having a foot ulcer. It needed to be simple, cheap and accurate. They looked at people’s risk of ulcers 2 years after a foot check.

What’s new?

Researchers analysed data from 4 international research studies. The studies included adults with diabetes who were free of ulcers at the start. They were conducted in primary care and in specialist clinics, often in hospitals, in Europe and the USA. The researchers used data from these studies to develop a tool to assess risk of foot ulcers in people with diabetes.

The tool assigns points to 3 pieces of information: insensitivity, foot pulse and previous history.

  • 0 points: no problem on any test
  • 1 point: insensitivity (pressure is applied with an instrument called a monofilament to spots on the sole of the foot to see if the person can feel it)
  • 1 point: no foot pulse (pedal pulse) in either foot
  • 2 points: previous history of ulcers or amputation.

Points are added up to give an overall score of 0 to 4. The overall score indicates the risk of developing a foot ulcer within 2 years:

  • 0 points = 2% risk of ulcers
  • 1 point = 6% risk
  • 2 points = 14% risk
  • 3 points = 29% risk
  • 4 points = 51% risk.

The tool was tested in the UK using data from a fifth study including 3324 adults. Again, participants had diabetes but no ulcers. They were aged 67 years on average.

The tool correctly identified people who would develop ulcers, and people who would not, 83% of the time. The researchers concluded that anyone with a score of 1+ (a risk of 6% or more) would benefit from intervention to prevent foot ulcers. More than half of the participants scored less than 1 and may not need preventive measures.

Why is this important?

Previous methods for predicting foot ulcers were either complicated, untested, or did not give a risk score. This tool is easy to use and could identify those who would benefit most from preventive measures. It uses data routinely gathered during foot examinations and usually recorded in health records. It is inexpensive and could be widely used.

Use of the tool could ensure that NHS resources are spent on those most at risk. A study by the same group showed that few people (5%) change their score in 2 years. Testing could therefore be carried out every 2 years (rather than every year, as is currently done). This would reduce the burden on diabetes services.

Preventing foot ulcers can ultimately reduce amputations and premature deaths. The researchers caution that small risks of developing foot ulcers should not allow people to become complacent. Good health for people with diabetes depends on good self-care. The research team stress that this tool is no substitute for people regularly checking their own feet. If they notice a problem, they should seek medical advice to stop it getting worse at the first opportunity.

What’s next?

This tool does not depend on IT systems, and can be used by a range of professionals. It can be printed out or made available electronically, and is easy to remember. However, it will need to become part of clinical systems to be widely used.

UK guidance currently asks for 8 -10 pieces of information. Guidelines from NICE and the Scottish Intercollegiate Guideline Network (SIGN) are about to be updated. The researchers hope this tool will be recommended for use in community health care settings.

The tool needs to be tested further in specialist hospital settings. It also needs to be tested alongside preventative measures to see how much they improve outcomes for people with diabetes.

You may be interested to read

This NIHR Alert is based on: Chappell FM, and others. Development and validation of a clinical prediction rule for development of diabetic foot ulceration: an analysis of data from five cohort studies. BMJ Open Diabetes Research & Care 2021;9:e002150

Information from Diabetes UK: Serious foot problems and diabetes

Information from the NHS Northern England Clinical Networks: Diabetes - Foot Ulcers

A report from the North West Coast Strategic Clinical Network: Diabetes footcare pathway blueprint

NICE guideline [NG19]. 2015: Diabetic foot problems: prevention and management

Evidence for preventive measures: Crawford F, and others. Preventing foot ulceration in diabetes: systematic review and meta-analyses of RCT data. Diabetologia 2020;63:1

Evidence about the interval between checks: Heggie R, and others. Complication rate among people with diabetes at low risk of foot ulceration in Fife, UK: an analysis of routinely collected data. Diabetic Medicine 2020;37:12

Funding: This study was funded by the NIHR Health Technology Assessment programme.

Conflicts of Interest: Commentator Neil Reeves has worked closely with two of the co-authors but had no involvement in this paper.

Disclaimer: NIHR Alerts are not a substitute for professional medical advice. They provide information about research which is funded or supported by the NIHR. Please note that views expressed in NIHR Alerts are those of the author(s) and reviewer(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.


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Comments

Study author

Treatment of foot ulcers and amputations costs the NHS £837 – £962 million per year. This is nearly 1% of the total NHS budget, and most of the cost (90%) relates to foot ulcers. They can lead to amputations and early death so people at risk need to be identified before the damage occurs.

We were pleased to find that 3 risk factors can predict foot ulcer risk and we recommend prevention strategies for anyone with a risk score of 6% or higher. Even using this low cut-off, the tool is still cost-effective and useful. We are testing it further alongside preventive therapies. We want to see what difference treatment can make to people with diabetes.

Francesca Chappell, Medical Statistician, University of Edinburgh 

Specialist diabetes doctor

The paper re-emphasises the importance of foot screening and risk assessment in people with diabetes. It quantifies the risk of developing foot ulcer using existing information and usual UK screening tests. Community foot protection services will find this useful. It will also help commissioners assess the disease burden and the population’s likely needs in future.

This model is largely based on data from the UK and other countries in the West. It would be good to see it validated further in larger studies from elsewhere. In addition, the coding of electronic records may need to be modified to automate the process.

Saifuddin Kassim, Consultant in Diabetes and Endocrinology, Leeds Teaching Hospital NHS Trust 

Researcher

This paper could influence policy on diabetic foot ulcer screening and the frequency of screening for specific risk category groups.

The findings strike a good balance between detailed measurement and ease and simplicity of use. Other measures might be more sensitive but they would be more involved and time consuming and less likely to be used in clinical practice. The 3 selected measures represent a good balance and are perfectly feasible. They enhance the real-world application of these findings. The scoring system is clear and would be straightforward to apply.

This paper helps to direct and shape future research efforts in this area. The outcome measures are highly applicable to, and simple to apply in clinical practice, ensuring a high degree of relevance for translating these research findings to clinical practice.

Neil Reeves, Researcher, Manchester Metropolitan University 

Researcher

This tool could have an impact because it is easy to use. A simple calculation of risk factors determines whether someone is likely to have a foot ulcer. Finding the people at greatest risk will help them access the right treatments. Overall, this could represent a huge cost saving to the NHS.

This clinical risk score should be part of every basic assessment that people have with a healthcare provider.

Amy Harwood, Researcher, Coventry University

Lived experience

I am living with type 2 diabetes and run a patient support group. This information is directly relevant to me and I will discuss it with my group members, their families and friends who are also living with the condition.

Your risk of ulcers isn’t usually made clear. A large percentage of patients are just told that their feet are OK. This research should make it easier to understand the risk you have.

For this research to have an impact for both healthcare professionals and patients, there needs to be more advertising and education about the importance of annual reviews for people living with diabetes.

Angelina Whitmarsh, Public Contributor, Southampton

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