Quantitative Vibration Perception Threshold in Assessing Diabetic Polyneuropathy: Should the Cut-off Value Be Adjusted for Chinese Individuals with Type 2 Diabetes?

Aims/introduction: To examine the performance and identify the optimal threshold of vibration perception threshold (VPT) for diagnosing diabetic polyneuropathy (DPN) in a Chinese population according to multiple definitions of DPN as gold standards.

Materials And Methods: VPT was determined in 421 Chinese individuals with type 2 diabetes, who simultaneously completed a questionnaire of neuropathic symptoms, and underwent the assessment of signs of peripheral neuropathy and electromyography tests. Three definitions of DPN (i.e., clinician-diagnosed DPN, abnormal nerve conduction and confirmed DPN) were taken as reference gold standards.

Results: Vibration perception threshold was a specific measure for all three groups of DPN outcomes, with the highest specificity noted for clinician-diagnosed DPN (85.1%). The specificity for abnormal nerve conduction and confirmed DPN was 77.0 and 76.6%, respectively. The sensitivity of VPT was 67.0% for clinician-diagnosed DPN, 66.5% for abnormal nerve conduction and 67.2% for confirmed DPN. The optimal cut-off threshold for abnormal nerve conduction, as well as confirmed DPN, was VPT >14.9 V. The specificity and sensitivity of VPT >14.9 V as the cut-off value for clinician-diagnosed DPN were 85.6 and 66.2%, respectively. When taking clinician-diagnosed DPN as the gold standard, the performance of VPT for diagnosing DPN was best with an area under the curve value of 0.804.

Conclusions: VPT measured using the neurothesiometer had relatively high specificity and best performance for diagnosing DPN when clinician-diagnosed DPN rather than abnormal nerve conduction was taken as the gold standard in a Chinese population. A VPT value of ≥15 V might be equally applicable for diagnosing DPN in a Chinese population.