Handheld devices that can detect the telltale signs of peripheral neuropathy in people with diabetes could have another important function—predicting the risk that they will die within the next few years, according to a new study.
One of the devices’ manufacturers, Massachusetts-based NeuroMetrix, said the finding reveals the importance of testing as early as possible for diabetic peripheral neuropathy (DPN), as it gives an opportunity to treat patients earlier and—potentially at least—alter the trajectory of their disease.
DPN is a common complication of diabetes and generally causes symptoms like weakness, numbness, pain and “pins-and-needles” in the hands and feet, but is insidious, often having no symptoms initially. It can lead to the formation of diabetic foot ulcers, which are a major cause of medical amputations.
NeuroMetrix’s DPNCheck device detects it by measuring large nerve fiber conduction velocity and response amplitude in the sural nerve of the lower leg, typically within around 15 seconds.
The new study run by researchers at the University of Sheffield in the U.K. compared DPNCheck to another device called Sudoscan that works in a similar way but monitors small nerve fibers in the hands. It is manufactured by a company of the same name, formerly known as Impeto Medical, which was acquired by smart device marker Withings last year.
Both devices have been validated as being able to detect DPN, and they were compared in the study to two conventional clinical exams based on symptoms assessment and reflex and sensory function tests, namely the Toronto Clinical Neuropathy Score scale and Semmes-Weinstein Monofilament test (10 g-MFT).
The 245-subject study followed diabetic patients for seven years, after which 52 of them had died. After adjusting the data to correct for differences in the patient groups in baseline, such as age, elevated cholesterol levels and glucose control measured using the HbA1c biomarker, only the devices were able to predict the risk of dying from any cause.
The clinical exams were not able to predict mortality, according to the researchers behind the work. They rely on simple bedside instruments to measure small fiber function by seeing if patients can detect temperature and pinpricks, and large fiber function using a tuning fork. While widely used, the tests are subjective and depend on the clinical skills of the clinician, and in this study were only able to detect DPN at a more advanced stage.
The Sheffield researchers have previously proposed that point-of-care devices like DPNCheck and Sudoscan should be used in combination to screen for DPN, with any individual with a positive result referred to treatment aimed at controlling their blood glucose levels and reducing cardiovascular risk factors, as well as programs to modify their lifestyle. The new data provide further evidence of the benefit of that approach.
NeuroMetrix CEO Shai Gozani hailed what he said was a “landmark study,” which shows that “only objective assessments of DPN are predictive of mortality.”
"The implication is that early stage DPN puts the patient at risk for devastating health complications,” he added. “However, early detection and intervention have the potential to alter the patient’s disease trajectory."