Diagnostic accuracy of screening tests for diabetic peripheral neuropathy among outpatient attendees of follow up care for diabetes in Central India

Abstract Background and objectives: Of the several screening tests used in screening for Diabetic Peripheral Neuropathy (DPN), each one has its demerits which act a threat to reliability. There is no single optimal method for the early diagnosis of Diabetic Peripheral Neuropathy (DPN). This study was conducted to compare the diagnostic accuracy of monofilament, biothesiometer and symptom-based scoring in detecting DPN, to determine the optimal cut-off for biothesiometer score compared to Nerve conduction studies (NCS) as gold standard and to compare the time taken to screen with monofilament and biothesiometer. Methodology: The cross-sectional comparative diagnostic accuracy study was conducted in the Medicine OPD of a tertiary care institute in Central India. Among the patients with DM, those who were advised NCS between March - October 2023 were included in the study. All patients had undergone clinical Michigan neuropathy scoring, biothesiometer and monofilament and NCS. Results and discussion: A total of 78 limbs among 39 patients with diabetes were assessed for DPN. The sensitivity of clinical Michigan neuropathy scoring, monofilament and biothesiometer (10 cut-off) were 15.6% (5.3 to 32.8), 35.5% (23.7 to 48.7) and 71% (58.1 to 81.8) respectively. A biothesiometer score of 10 was identified as optimal with area under the curve: 0.7132 (0.56 to 0.87), and the time taken to administer the biothesiometer was about 2.5 times more compared to the monofilament assessment. Conclusions: Biothesiometry has higher sensitivity compared to other screening methods such as monofilament and clinical symptom score. The biothesiometer cut off at 10 had higher sensitivity compared to the existing standards of 15mV. The need for lower cut-off for biothesiometry has to be established with reference to nerve conduction study standards in larger studies.