Neuropathy very common, but underdiagnosed, study says
1 of 2 | “Neuropathy is a painful, disabling condition for many people who have it. It affects their, their overall quality of life and often leads to depression,” said the study’s lead author, Dr. Melissa Elafros, an assistant professor of neurology at the University of Michigan Medical School. Photo by Douglas Pike/Hurley Medical Center
Neuropathy — nerve damage that causes pain, numbness, weakness or tingling in the feet and hands — is very common and underdiagnosed, a new study indicates.
The study, conducted through a partnership between the University of Michigan in Ann Arbor and Hurley Medical Center in Flint, was published Wednesday in Neurology, the medical journal of the American Academy of Neurology.
In some cases, neuropathy can eventually lead to falls, infections and even amputations, the study’s authors noted.
“Neuropathy is a painful, disabling condition for many people who have it. It affects their sleep, their overall quality of life and often leads to depression,” said the study’s lead author, Dr. Melissa Elafros, an assistant professor of neurology at the University of Michigan Medical School.
“Unfortunately, there is no disease-modifying treatment for neuropathy — meaning the best that we can do for many people is trying to decrease their pain and prevent falls or infections from injury to their feet,” Elafros said.
Researchers assessed 169 people from an outpatient internal medicine clinic that serves primarily Medicaid patients in Flint, Mich. The participants, with an average age of 58, were 69% Black.
“Minority and low-income communities are often under-represented in clinical research,” Elafros said, noting that “currently, the accepted prevalence rate for neuropathy is 13.5%. Yet, in our population, it was 73%.”
Fewer than 20% of people with neuropathy were aware of their condition.
“This is a big problem because that means they are likely not doing the things that can prevent falls, infections and even eventual amputations,” Elafros said.
One-half of those studied had diabetes, which can injure nerves throughout the body and result in neuropathy.
A total of 67% had metabolic syndrome — defined by the presence of excess belly fat plus two or more of the following risk factors associated with neuropathy: high blood pressure, higher than normal triglycerides, high blood sugar and a low level of high-density lipoprotein cholesterol, or “good” cholesterol.
A total of 73% of participants had neuropathy. Of these people, 75% had not been previously diagnosed. Almost 60% of those with neuropathy were experiencing pain. Of those with neuropathy, 74% had metabolic syndrome, compared to 54% of those who did not have it.
After adjusting for other variables that could impact the risk of neuropathy, researchers found that people with metabolic syndrome were over four times more likely to have neuropathy than people without the syndrome.
“The big takeaway message of this work is that neuropathy is likely more common than we think,” Elafros said. “By underdiagnosing neuropathy, we miss a valuable opportunity to counsel patients to improve their well-being.”
Researchers also explored any connection between race and income and neuropathy, as few studies have delved into those issues. There was no link between low income and neuropathy.
Black people had a lower risk of neuropathy. They comprised 60% of participants with neuropathy and 91% of those without the condition.
The study was a joint effort between providers at Hurley Medical Center in Flint and researchers from the University of Michigan.
“One thing that I learned was how hard it can be to screen for neuropathy in a busy primary care clinic,” Elafros said. “Our team is capitalizing on this collaboration to help improve care for neurologic diseases in places like Flint.”
She added that “this study is just a snapshot in time at one clinic in Flint. It does not tell us how quickly people develop neuropathy in this clinic.” In addition, it may not represent other parts of the city.
The study received support from the National Institute of Neurological Disorders and Stroke, National Institute of Diabetes and Digestive and Kidney Diseases and National Center for Advancing Translational Sciences.
“It’s an outstanding study and really important. Peripheral neuropathy is a widespread problem in the U.S. population,” said Dr. David Herrmann, a professor of neurology and pathology at the University of Rochester Medical Center in Rochester, N.Y., who was not involved in the research.
As many as 10% of people will develop neuropathy in their lifetime. This study suggests that peripheral neuropathy is even more frequent in minority and underserved groups, Hermann said.
The study presents an “incredible opportunity” to raise awareness that neuropathy is “a common consequence” of metabolic syndrome, including diabetes, obesity, abnormal blood lipids and high blood pressure, he said, adding that “this is clearly a public crisis.”
Neuropathy is under-diagnosed because “symptoms often start off quietly in the background — a little numbness or tingling in the feet, a little difficulty wiggling the toes, some trouble with balance or unexplained falls,” said Dr. Maxwell Levy, an assistant professor of neurology and associate residency program director at Tulane University School of Medicine in New Orleans.
“However, it can progress over months to years to be more disruptive and disabling. People should be sure to bring these symptoms to their doctor’s attention, so they can be screened for medical conditions that cause neuropathy,” Levy said.
“There is no single blood test or imaging study that will diagnose neuropathy. A neurologist can perform a nerve conduction test to further characterize the subtype of a neuropathy or can determine if neuropathy is present in uncertain cases,” he said.
It’s important to diagnose and treat neuropathy appropriately as early in the condition’s course as possible, said Dr. Vishakhadatta Mathur Kumaraswamy, an assistant professor of neurology and neuromuscular medicine at the University of Kentucky College of Medicine in Lexington.
“Delay in treatment of the underlying cause of neuropathy may lead to poorer outcomes in the form of incomplete recovery or permanent disability from weakness or gait imbalance,” Kumaraswamy said. “It also increases the chances of potentially preventable complications, such as falls, joint deformities and nonhealing wounds.”
The high prevalence of diabetes and metabolic syndrome in the study may not be completely representative of the patient population, said Dr. Ashley Weng, an assistant professor of neurology at Rutgers Robert Wood Johnson Medical School in New Brunswick, N.J.
Participants were selected when they came to the clinic for routine care, so the study may skew toward sicker patients who seek help, Weng said. Also, she noted, “It is possible that those with symptoms of neuropathy were more interested in participating.”