Screening for peripheral artery disease among diabetics using sudomotor function testing

Abstract

Objective To explore the relationship between sudomotor function and peripheral artery disease (PAD), and to evaluate the effectiveness of sudomotor function testing to screen diabetic patients at high risk of PAD comparing to ankle-brachial index (ABI) and toe-brachial index (TBI). Methods A total of 263 diabetes mellitus (DM) outpatients in the 306th Hospital of PLA from August 2014 to April 2015 were enrolled in the study. ABI and TBI were measured by the Doppler method. Sudomotor function was evaluated by measuring the electrochemical skin conductance (ESC) of the hands and feet using the Sudoscan instrument. Cardiovascular autonomic neuropathy (CAN) was assessed and recorded as cardiac autonomic neuropathy risk-score (CAN-RS) by Sudoscan. Results ESC values of the feet and hands were positively correlated with ABI and TBI. The diabetes patients with abnormal ABI and TBI had significantly lower hand ESC [(45.63±12.87) µS vs. (68.10±17.40) µS, (59.17±19.58) µS vs. (68.57±17.11) µS; P< 0.05] and feet ESC [(44.54±25.48) µS vs. (70.92±19.46) µS, (59.21±24.52) µS vs. (71.71±19.02) µS; P< 0.05], and higher CAN-RS[(49.17±15.41)% vs. (36.33±16.25)%, (44.90±16.09)% vs. (35.39±16.05)%; P< 0.05], than diabetes patients with normal ABI and TBI. Using ABI as the gold standard, the areas under the receiver operating characteristics (ROC) curve of the diagnostic performance of hands ESC, feet ESC and CAN-RS to identify PAD were 0.87, 0.84 and 0.74, respectively (P<0.001). Conclusion Sudomotor function testing can be helpful and beneficial to identify PAD in patients with diabetes. Key words: Peripheral artery disease; Ankle-brachial index; Toe-brachial index; Sudomotor function