Vibration-based neuropathy detectors vary widely.
"This would significantly reduce the proportion of patients with diabetes who would be falsely identified as having no peripheral neuropathy and subsequently denied the benefit of beneficial and effective secondary risk factor control," said study coauthor Cynthia Formosa, PhD, of the University of Malta, Msida, and Staffordshire University, Stoke-on-Trent, England, in an interview.
Researchers have estimated that 50% of patients with diabetes develop diabetic polyneuropathy over their lives, and that the condition is responsible for more than a quarter of all diabetes spending. "Despite a long history of research in this area, we are only starting to understand the pathophysiology of the disease," reports a 2016 review of recent findings.
In a previous report, several of the authors of the new study analyzed 10 sets of guidelines regarding diabetic foot and found that some lacked information to back up the recommendations. Guideline limitations "are responsible for the current gaps between guidelines, standard clinical practice, and development of complications," the researchers wrote (Rev Diabet Stud. 2016, 13[2-3]: 158-86).
Most of the guidelines recommended the use of a 10-g monofilament test, in which a monofilament is placed against the skin, plus a vibration-based test, the researchers reported.
For the new study in Primary Care Diabetes, the researchers examined the efficacy of three noninvasive tools that are used to detect neuropathy in the foot: the 128-Hz tuning fork; the VibraTip, a pocket-sized, motorized device; and the neurothesiometer, a 7-pound electromechanical device that comes in a carrying case and includes an attachment that delivers vibrations to the body.
According to Dr. Formosa, the tuning fork is the most commonly used testing device in normal clinical practice. Physicians such as endocrinologists and podiatrists use the vibrations produced by the devices to detect whether patients have normal levels of sensation in various parts of the foot and ankle. "Vibration testing is extremely important," the study investigators wrote, "since in the initial stages of neuropathy, the vibratory sensory system is amongst the first component of the nervous system to be affected."
However, research into the accuracy of the devices has been inconsistent, according to the investigators.
The researchers prospectively recruited 100 patients at primary health centers diagnosed with type 2 diabetes for at least 10 years. The subjects included 57 males and 43 females, with a mean age of 73 years ([+ or -] 7.8 years). Practitioners tested the neuropathy detection tools on the patients and recorded whether they felt vibrations.
The study authors reported that 29% of patients didn't perceive vibrations produced by the VibraTip, compared with 21% for the neurothesiometer and 12% for the 128-Hz tuning fork (P less than .001). The VibraTip device is available for about $90 on Amazon. The cost of a neurothesiometer is listed by one medical supply company as $2,850. Prices for 128-Hz tuning forks vary on Amazon, with prices listed from $6 to $40.
The study researchers did not confirm neuropathy via more sophisticated neurologic testing, so it remains unclear which device is actually the most accurate at detecting cases of neuropathy. Still, "the findings of this study suggest that use of only one screening tool to assess vibration perception is likely to yield high false negative results. We recommend that peripheral neuropathy in patients with diabetes should be assessed utilizing two or more modalities," they wrote.
If results don't concur, neurologic testing may be appropriate, study senior author Nachiappan Chockalingam, PhD, also of the University of Malta and Staffordshire University said in an interview. Moving forward, Dr. Chockalingam said, the research team plans to launch "a structured clinical trial using a gold-standard tool such as nerve conduction testing to confirm which simple screening method best detects neuropathy."
No study funding was reported. The authors reported no relevant disclosures.
SOURCE: Chockalingam N et al. Prim Care Diabetes. 2018 Apr;12(2):111-5.
BY RANDY DOTINGA
FROM PRIMARY CARE DIABETES
Caption: Dr. Chockalingam
Please Note: Illustration(s) are not available due to copyright restrictions.
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|Publication:||Family Practice News|
|Date:||May 15, 2018|
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