'One-Stop Shop' for Diabetic Neuropathy Along With Eye Screening

September 14, 2016

MUNICH — Assessing patients for diabetic neuropathy while they are having their eyes examined may be a quick and convenient way of identifying early those who are at risk of nerve damage.

Anyone pinpointed could be referred to a special clinic for aggressive risk-factor management, said the doctor who is pioneering the research.

At the European Association for the Study of Diabetes (EASD) 2016 Annual Meeting, Solomon Tesfaye, MB ChB, MD, FRCP, of the Royal Hallamshire Hospital, Sheffield, United Kingdom, described the "one-stop shop" they are studying in a hospital clinic in Sheffield, whereby diabetes patients coming for retinopathy screening also have their feet assessed using two new state-of-the-art point-of-care devices.

These are the DPNCheck (NeuroMetrix) — a handheld device that takes 3 minutes to provide a reading and assesses large-fiber nerve-conduction velocity and amplitude — and Sudoscan (Impeto Medical), a device that assesses small nerve fibers. With the latter, which also takes about 3 minutes to perform, patients put their hands and feet on metal plates that detect the ions in their sweat, thereby indirectly providing a measure of any small-nerve–fiber damage.

So "in the 15 minutes the patients are waiting for the eye drops to take effect, they can take off their socks and shoes and have their feet examined," Dr Tesfaye said. Of the 180 patients in this feasibility study, 80% thought it was "fantastic. Everything was done in one appointment," he observed.

But commenting, chair of the session Andrew Boulton, MD, DSc, FRCP, of the University of Manchester, United Kingdom, wondered whether this approach "was feasible to be rolled out, or is it too intensive for everyday practice?"

Dr Tesfaye acknowledged that "more work is required on this, but there is great potential."

To Medscape Medical News, he elaborated that there are three further steps to be completed before this could be more widely employed. "One, we need to see how cost-effective this is. Two, we need to prove that these devices predict diabetic neuropathy down the line; and three, we need to show that if we can detect diabetic neuropathy early, we can reverse it."

The latter has been demonstrated before, he stressed, but "we need to prove this in the modern age."

Current Assessment for Diabetic Neuropathy Is "Too Crude"

Dr Tesfaye said the United Kingdom is a world leader in screening for diabetic retinopathy, due to a directive 10 years ago that decreed that everybody with diabetes should have annual eye screening with retinal photography.

Before this, "we were fiddling with ophthalmoscopes, and blindness was missed," he explained. Now, trained technicians in hospital clinics take a picture and grade it and refer anyone of concern to an ophthalmologist, he explained.

"So now we are doing well, and diabetic retinopathy is no longer the most common cause of working-age blindness," he told Medscape Medical News.

But in neuropathy, "we are still using very crude measures, the 10-g monofilament [MF] test," which general practitioners get reimbursed for conducting, he noted.

Although he acknowledged this is a way of diagnosing "dead feet," it detects nerve damage only "when it's too late and irreversible, and it is not a good way of detecting early neuropathy."

Foot clinics are therefore bursting with patients and amputations are increasing year on year, he noted, stressing that a more effective model for foot screening is desperately needed.

And although there is a very good gold standard, the Toronto Clinic Scoring System (TCSS) employed by podiatrists, this requires expertise and wouldn't be feasible for a busy screening clinic, he noted.

"We need to have the same kind of paradigm shift that we had in retinopathy in neuropathy, using proper equipment," he stressed.

One-Stop Shop for Diabetic Complication Assessment

In this pilot study, Dr Tesfaye reported on the first 180 consecutive diabetic patients who attended their clinic, 20.5% of whom have never had their feet examined previously. Almost 50% of people had not had any general foot education either, he noted.

The researchers set out to assess the feasibility and patient acceptability of the combined eye and foot screening (and also renal, if required, which was done using standard blood tests).

The prevalence of diabetic peripheral neuropathy (DPN) as determined by the new devices and the 10-g MF test was compared with the TCSS employed by podiatrists. The latter "is an excellent test," said Dr Tesfaye but necessitates specialists in attendance, whereas the idea here is that, ultimately, technicians could perform these tests for DPN using the new devices.

Consecutive patients attending eye screening had their feet examined, which included TCSS (which took 10 minutes), the 10-g MF test (2 minutes), and assessments with DPNCheck and Sudoscan (3 minutes each).

The prevalence of DPN using the TCSS was 31.6%.

In contrast, the prevalence of DPN using the 10-g MF test was 12.4%, so the latter massively underestimated the risk, Dr Tesfaye noted.

Using the newer devices, the prevalence using DPNCheck was 55% (91% sensitivity, 73% specificity), 40% using Sudoscan (79% sensitivity, 60.3% specificity), and 50.3% using abnormality in either (94% sensitivity, 63% specificity).

Both devices correlated with TCSS (P < .001), and a new diagnosis of painful DPN was made in 12% of patients.

Identifying Diabetic Neuropathy Early Has "Great Potential"

Dr Tesfaye told Medscape Medical News that the DPNCheck device currently costs around $500 to $1000 (€445–€890) and the Sudoscan is around €25,000.

But "these devices are diagnosing real abnormalities," he noted, saying their costs need to be viewed in the context that one patient with a diabetic foot ulcer "costs the UK NHS £7000 a year," and every amputation of a foot costs £40,000 and results in "exceedingly high mortality — 50% of patients are dead within 2 years."

And £2 billion is spent a year in total on diabetic foot in the United Kingdom.

In terms of further assessing this, he acknowledged: "We need to gather more information, we need to look at the cost utility of these devices — we think you don't need the clinical exam because this requires expertise — but [with these devices] the exam can be done by a technician with very little training.

"We have to roll this out to the whole of Sheffield, see its impact on foot ulcers and the prediction of neuropathy down the line, and demonstrate that, if we diagnose subclinical neuropathy, we can reverse it."

He believes that reversal is possible. "We know what drives nerve damage: it's not just about glucose control, but about blood pressure, smoking, and obesity. If people know they are at risk of losing their feet, it makes them think. If we detect early neuropathy, we will put people in a special clinic for aggressive risk-factor management."

"We have old evidence that this works but we need to build a contemporary evidence base to prove it," Dr Tesfaye told Medscape Medical News.

Dr Tesfaye declares honoraria from Astellas Pharma, Worwag Pharma, and Miro and lecture and other fees from Pfizer, Eli Lilly, Novo Nordisk, and MSD.

Follow Lisa Nainggolan on Twitter: @lisanainggolan1. For more diabetes and endocrinology news, follow us on Twitter and on Facebook.

European Association for the Study of Diabetes (EASD) 2016 Meeting; September 13, 2016; Munich, Germany. Abstract OP-06.31.

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