Step in the right direction

An insole for diabetics that monitors the temperature of a wearer’s foot could help prevent thousands of foot amputations a year, its developer has claimed.


An insole for diabetics that precisely monitors the temperature of a wearer’s foot could help prevent tens of thousands of foot amputations a year, its developer has claimed.

About to undergo trials in the US, the Shoepod Diabetic, developed by New Zealand firm Zephyr Technology, integrates smart fabric technology to spot the early warning signs of Diabetic Peripheral Neuropathy (DPN), a disorder caused by diabetes where nerve damage affects sensation in the limbs.

DPN sufferers typically lose the ability to feel pain in their arms and legs, and if they sustain an injury in these areas there is an increased risk of developing an ulcer.

Sufferers are least likely notice damage to the feet, where, compounded by issues such as poor posture or even ill-fitting shoes, the problem can become particularly dangerous.

The device weighs around 2oz (less than 50g) and can transmit data wirelessly to a mobile phone or USB radio receiver for download to a PC. Real-time and trend analysis software is integrated into the Shoepod Diabetic, and it can hold up to three months’ worth of data which can then be sent to a specialist for more detailed analysis.

According to Chris Hardaker, Zephyr’s project manager, this surprisingly common condition is one of the leading causes of foot amputation, and the economic and personal costs of dealing with it are high.

‘When a diabetic gets an ulcer on the foot the treatment costs the US health system between $4-6,000 (£2-3,000),’ he said. ‘If it goes untreated long enough an infection can develop, which can get into the bones of the foot and means the sufferer has to have it amputated. In the US 85,000 diabetics a year have amputations because of ulcerated feet — each one costing around $60,000.’

These shocking claims are brought closer to home with the release of the latest figures from the NHS Information Centre, which indicate that of the estimated 2.35 million diabetics in the UK, just over a third are having all of the recommended tests carried out. There are understandable fears that this country could be facing a DPN timebomb.

Hardaker explained that the foot goes through a series of phases before an ulcer forms: from normal to calloused skin, to inflammation and finally ulceration. The Shoepod Diabetic is, he said, able to detect an ulcer prior to it actually forming using a system that carefully measures and analyses the range of temperatures across the sole of the foot. ‘We’re taking temperature readings in the foot and running a whole load of analyses over those readings.

‘There are ways of watching those temperatures that enable you to see how the foot is being used or misused, and look for the earliest possible sign that you’re heading down the path towards ulceration. We can detect the build-up of potential callous material and then say to the diabetic “you are at a pre-ulcerous state. Now is the time to take some action.”‘

Throughout the development of the system, Zephyr has worked closely with world-leading podiatrist Dr David Armstrong at the Scholl College of Podiatric Medicine in the US, where the system is about to undergo stringent trials.

Hardaker is confident that the product will enjoy a relatively smooth and rapid route to market.

‘If you can come up with a compelling enough statement you can get through the paperwork reasonably efficiently,’ he said. ‘I’m hopeful that the product will be on the market next year. we are confident in our technology and we are working with the man who is considered to be the world’s leader in diabetic foot care.’

Zephyr, which also produces smart-fabric devices for the athletics market believes that demand for the Shoepod Diabetic could run into tens of millions of units a year.