Sudomotor dysfunction in people with type 1 diabetes with and without clinical peripheral neuropathy: A study from Pune, India

BACKGROUND AND AIMS: It is appreciated that current screening tools for diabetic peripheral neuropathy (DPN) often fail to detect early disease. Sudomotor (sweat gland) dysfunction, among the earliest manifestations of DPN, can be measured objectively by the SUDOSCAN® device. We compared SUDOSCAN® with conventional validated screening (Michigan Neuropathy Screening Instrument or MNSI) in type 1 diabetes (T1D). METHODS: T1D participants (n = 264, 46.2% male, mean age 26.3 years, mean diabetes duration 13.2 years) enrolled in the prospective PICTURE study (Diabetes Unit, KEM Hospital, Pune, India) underwent simultaneous assessments for sudomotor dysfunction (electrochemical skin conductance ESC <60 μS indicating dysfunction) and DPN (MNSI) and were classified as: (a) MNSI abnormal ('clinical DPN'), (b) MNSI normal, but ESC <60 ('subclinical DPN) and (c) Both normal ('no neuropathy'). RESULTS: Sudomotor dysfunction was more common than clinical DPN (46.2 vs 22.3%) with a sensitivity of 72.8% and specificity of 61.4% for detecting clinical DPN. Those with sudomotor dysfunction (ESC <60 μS) were 4.3 times more likely to have clinical DPN compared with participants without sudomotor dysfunction (ESC ≥60 μS). Among participants with normal MNSI (i.e., without clinical DPN), subclinical DPN was detected in 38.5% and was associated with younger age, shorter duration of diabetes, anemia, vitamin D deficiency, and microvascular complications. CONCLUSION: Sudomotor testing is an objective and sensitive method for DPN screening in T1D, aiding early detection.