Objectives: Explore the potential of using niacin-induced skin flushing response (NSFR) as a diagnostic method for diabetic peripheral neuropathy (DPN) based on the microangiopathic characteristics of DPN.
Methods: This study involved 114 diabetic patients (51 with DPN, 59 without DPN, and 4 with an undetermined diagnosis) and 91 healthy controls(HC). DPN was assessed through clinical symptoms and/or signs, quantitative sensory tests, and electromyography. NSFR is detected using a modified 6-chamber sandwich patch and six different concentrations of aqueous methyl nicotinate (AMN). The sum of the 6 AMN concentrations' flushing area scores within 10 minutes after reaction were calculated and defined as the total NSFR score.
Results: NSFR to gradient concentration stimulation of AMN is reduced and delayed in diabetes patients compared to HCs, and the total NSFR score was significantly decreased (6827.3 (5038.45) vs. 10680 (5060.2)mm2, P < 0.001). The decline in NSFR was more pronounced in diabetes patients with DPN compared to those without DPN (4517.9 (3909.3) vs. 8896.5 (5179.7)mm2, P < 0.001). The association between NSFR and diabetic neuropathy was further evaluated using a multinomial logistic regression model. After adjusting for covariates that might affect NSFR or neuropathy (including age, sex, diabetes duration, BMI, fasting C-peptide, and HbA1c), NSFR was still independently associated with diabetic neuropathy (odds ratio: 0.903 (95% CI: 0.843-0.968), P=0.004). The optimal cut-off point of total NSFR score to distinguish diabetic neuropathy from non-diabetic neuropathy was 8530mm2, with a sensitivity of 88.2% and a specificity of 49.2%.
Conclusions: NSFR reduction is closely and independently associated with the existence of peripheral neuropathy in diabetic patients, and has great potential as an auxiliary tool in diagnosing diabetic peripheral neuropathy.
T. Jiang: None. F. Liu: None.
National Natural Science Foundation of China (82170827); Natural Science Foundation of Shanghai Science and Technology Commission(22ZR1450100); Shanghai Science and Technology Innovation Action Plan - Yangtze River Delta Region Collaboration Project(22002400600)
