Neuropathy patients more likely to receive high-cost, low-yield screening instead of more effective tests

U-M researchers found more efficient diagnostic tools are not always used, results reported in Archives of Internal Medicine

Ann Arbor, Mich. — Researchers at the University of Michigan analyzed the tremendous cost of diagnosing peripheral neuropathy and found that less expensive, more effective tests are less likely to be used.

Almost one-quarter of patients receiving neuropathy diagnoses undergo high-cost, low-yield MRIs while very few receive low-cost, high-yield glucose tolerance tests, according to the study that will be published Jan. 23 in the Archives of Internal Medicine.

The research was led by Brian Callaghan, M.D., assistant professor of neurology at the University of Michigan Medical School.

Patients diagnosed with peripheral neuropathy typically are given many tests but physicians are highly variable in their approach, says Callaghan.

“We spend a lot of money to work up a diagnosis of neuropathy. The question is whether that money is well spent,” Callaghan says.

For patients with peripheral neuropathy, the nerves that carry information to and from the brain don’t work property. This commonly leads to tingling or burning in arms or legs and loss of feeling — and the symptoms can go from subtle to severe.

Diabetes is the most common cause of this type of nerve problem. Peripheral neuropathy is found in about 15 percent of those over age 40.

Researchers used the 1996-2007 Health and Retirement Study to identify individuals with a diagnosis of peripheral neuropathy. They focused on 15 relevant tests and examined the number and patterns of tests six months before and after the initial diagnosis.

“Our findings, that MRIs were frequently ordered by physicians, but a lower-cost glucose tolerance test was rarely ordered, show that there is substantial opportunity to improve efficiency in the evaluation of peripheral neuropathy,” Callaghan says.

“Currently no standard approach to the evaluation of peripheral neuropathy exists . We need more research to determine an optimal approach. We do a lot of tests that cost a lot of money, and there’s no agreement on what we’re doing.”

The climbing rates of diabetes in the U.S. make this research even more important, says co-author Kenneth M. Langa, M.D., Ph.D., a professor of Internal Medicine at U-M, a Research Scientist at the VA Ann Arbor Healthcare System’s Center for Clinical Management Research, and Research Professor at the Institute for Social Research.

“We know more and more people may develop peripheral neuropathy because it is commonly caused by diabetes. Our study suggests that the work-up currently used for neuropathy isn’t standardized and tests that are less useful and more expensive may be used too often,” says Langa. “We need a more efficient way to handle this increasingly common diagnosis.”

Journal reference: Arch Intern Med. 2012; 172[2]:127-132.

Funding: National Institutes of Health, Katharine Rayner Program and A. Alfred Taubman Medical Research Institute. The Health and Retirement Study is supported by the National Institute on Aging.

Additional authors: Ryan McCammon, Kevin Kerber, M.D., Xiao Xu, Ph.D., and Eva Feldman, M.D., Ph.D.; all of the University of Michigan.

About the University of Michigan’s Department of Neurology: The department is an academic medical department with a full range of activities in patient care, education and research. The Neurology inpatient service provides care for acutely ill patients with neurologic disease and includes a dedicated intensive care unit, a separate stroke unit, and inpatient epilepsy monitoring beds. Our faculty also investigate the causes, treatments, natural history and phenotypic spectrum of inherited neurologic disorders, such as Alzheimer's disease. Our studies range from describing novel inherited neurologic syndromes; to family studies including genetic mapping; discovering genes for neurologic diseases; and the creation and analysis of laboratory animals of neurologic disease.

The University of Michigan also is a Neuropathy Association-designated Neuropathy Center of Excellence, a network of only 15 such institutions in the U.S. More information is available here.