Costly, ineffective tests used more often than more effective, but inexpensive tests to diagnose peripheral neuropathy
Peripheral neuropathy is a common
disorder, generally caused by
diabetes, which can cause distal
extremity numbness, tingling, and
pain. A new study found that the
evaluation of neuropathy in routine
practice represents an important
opportunity to improve the
efficiency and effectiveness of care.
The population of the study was
1,031 Medicare-age patients
evaluated for peripheral neuropathy
from the 1997–2007 Health and
Retirement Study's Medicare
claims-linked database.
The researchers found frequent use
of high-cost, low-yield magnetic
resonance imaging (MRI) and
infrequent use of low-cost, high-yield
glucose-tolerance tests that
indicate diabetes. In this study, 23
percent of the patients underwent at
least one MRI during the diagnostic
period for neuropathy, even though
this procedure is primarily useful
for identifying problems in the
central nervous system, not
peripheral nerves. The glucose-tolerance
test was performed in
only 1 percent of patients.
The researchers also found that
patterns of diagnostic test use in
neuropathy were highly variable.
Focusing on 15 relevant diagnostic
tests, more than 400 different
combinations of testing were found.
No single pattern of test ordering
occurred in more than 4.8 percent
of the patients, and no particular
test was common to all of the most
frequently used patterns.
A 2009 systematic review and
guideline statement by the American Academy of Neurology
found evidence for the effective use
of only four tests: fasting glucose
levels, vitamin B12 levels, serum
protein electrophoresis (SPEP), and
2-hour oral glucose-tolerance tests.
These tests detect neuropathy
related to diabetes or treatable
vitamin B12 deficiency. Both
abnormal glucose-tolerance test and
SPEP findings are known to be
substantially more common among
patients with neuropathy than
among control groups. In this study,
fewer than half of patients with
neuropathy received 1 or more of
these 4 tests, and only 17.3%
received 2 or more. Patients with neuropathy had mean
Medicare expenditures nearly twice
that of control patients during the
diagnostic period. This study was
supported in part by the Agency for
Healthcare Research and Quality
(HS17690).
More details are in "Tests and
expenditures in the initial
evaluation of peripheral
neuropathy," by Brian Callahan,
M.D., Ryan McCammon, A.B.,
Kevin Kerber, M.D., and others in
the January 23, 2012, Archives of
Internal Medicine 172(2), pp. 127-132, 2012.
— DIL
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