A Rapid, Low-Cost, Point-of-Care Test for Diabetic Peripheral Neuropathy
Abstract Number: 637-P
Authors: BONNIEJEAN BOETTCHER, BRIAN TRACEY, XUAN KONG, MIKE WILLIAMS, SHAI N. GOZANI
Institutions: Waltham, MA
Results: Annual screening for diabetic peripheral neuropathy (DPN) is recommended for early detection of this microvascular complication and to track its progression. The most widely utilized screening method is the 5.07/10-g monofilament. Nerve conduction studies (NCS) are the most accurate and reproducible test for DPN. However, they are not used for screening due to their expense, limited availability, and complexity. In response, we developed a fast, low-cost ($10-15), point-of-care sural nerve conduction velocity (CV) test. As a measure of nerve conduction, we hypothesized that the test would have a strong association with HbA1c.
Fifteen consecutive subjects (8 female) with diabetes mellitus (DM; 3 Type I, 12 Type II) who responded to study recruitment notices were evaluated. Ages ranged from 33 to 76 yrs and disease durations from 1 to 24 yrs. Sural CVs were measured bilaterally. In addition to the most recent HbA1c (range 4.7-10.3), the following variables were modeled: age, height, diabetes type and duration. The relationship between HbA1c and CV was evaluated by multivariate regression with the final model retaining variables at p<0.1.
Complete tests were performed in 29 sural nerves; excessive signal variability prevented evaluation of 1 nerve. The average data collection time was 10±5 (range 2-16) seconds per nerve. 25 nerves had a detectable response (>1.5 μV) from which a CV could be determined (range 23.3-48.8 meter/sec). The remaining 4 nerves were undetectable and no CV was reported. The regression analysis demonstrated a statistically significant (p=0.001) and clinically meaningful 2.1 meter/sec decrease in CV for every 1% increase in HbA1c. Age, height, and diabetes duration were also associated with CV.
In previous studies performed using traditional NCS techniques, sural CV decreased by about 1-3 meter/sec for every 1% increase in HbA1c. In the present study, point-of-care sural CV exhibited a similar association to HbA1c. However, unlike time consuming traditional techniques, this test required only 30-60 seconds per nerve including preparation. Rapid, low-cost, point-of-care sural CV testing has the potential to improve DPN screening.