This study included 560 type 2 diabetes hospitalized in the department of endocrinology, affiliated hospital of Chengdu University of Traditional Chinese Medicine from May 2016 to June 2018. The participants included 312 and 248 men and women, respectively .All experiments on human subjects were conducted in accordance with the Declaration of Helsinki and that all procedures were carried out with the adequate understanding and written consent of the subjects.
Inclusion and exclusion criteria
The inclusion criteria included the following: Patients who meet the diagnostic criteria of T2DM in the WHO criteria for diabetes diagnosis and classification (1999), conform to the diagnostic criteria of DSPN published by ADA in 2010, aged >18years, and participate voluntarily.
Moreover, the exclusion criteria included the following:
(1) Minor patients;
(2) Type 1 and a special type of diabetes;
(3) Recent acute complications of DM, including DKA, severe hypoglycemia coma and co-infected patients;
(4) Patients with severe liver function impairment (AST or ALT 2.5 times higher than the upper limit of normal), including patients with cirrhosis, severe hepatitis or severe cardiovascular and blood diseases;
(5) Neuropathy caused by other factors was diagnosed, including severe macrovascular abnormalities (thrombosis, etc.),cervical and lumbar problems (pinched nerve roots, narrow spinal canal, senile vertebral changes), cerebral infarction, Guillain-Barre syndrome, and neurotoxic and side effects caused by special drugs. The accumulation of toxic substances in the body caused by renal insufficiency causes nerve damage;
(6) Patients with other endocrine diseases that can significantly increase blood glucose, including hyperthyroidism, cortisolism, Cushing's syndrome, or those who have recently used glucocorticoids;
(7) Patients with mental illness, deformity or other reasons that cannot complete the test with the assistance of the detection personnel;
(8) Patients with a large area of scar, rash, vitiligo, or other infectious skin diseases on the ulnar skin of the left forearm.
After screening, samples are eliminated from the study if patients are not suitable for inclusion or exclusion criteria and incomplete data collection.
The reason for the removal of patient cases should be explained, and the statistical personnel and research team should make a plan to determine whether the case is deleted or not.
Detection methods of skin fluorescence AGEs
Test process: after calibrating the instrument, patients must fill in their basic information. Subjects will be seated at a constant room temperature (approximately 25°C) with their left forearm flat on the arm limit bracket, palms down, and the inner forearm skin (approximately 10-15 cm below the elbow) attached to the scanner probe. The forearm should be raised with the elbow as the fulcrum between each of the three scans until the forearm is removed from the probe and the forearm position is restored. The instrument automatically averages the three results and estimates the risk of four major complications. Note:The skin should not have visible blood vessels, scars, moss-like plaques, vitiligo, malformation, or other skin abnormalities. If the hair is strong, it should be removed and tested. Do not apply care cream or any fluorescent substance, including sunscreen or body lotion, and wash and dry with clean water before testing.
Participants were grouped according to three grouping criteria: P. J. Dyck criteria, full box results, and the Toronto Clinical Scoring System (TCSS).
P. J. Dyck criteria described the severity stages of neuropathy as follows: grade 0 (non-DPN group), diabetic group without neuropathy; grade 1 (early stage), asymptomatic neuropathy; grade 2 (middle stage), neuropathic symptoms are present, but without neurological involvement; and grade 3 (advanced), presence of neuropathic symptoms and functional involvement.
For full box results, vibration perception threshold (VPT) of <15 is the low-risk group, 15–25 is the medium-risk group, and >25 is the high-risk group. According to the detection results of the current perception threshold (CPT),it was divided into normal group, attenuated group and sensitive group.
For the TCSS, total scores of 0–5, 6–8, 9–11,and 12–19 points are classified as normal, mild, moderate, and severe, respectively.
The following data are collected: name, sex, age, course of illness, blood pressure, BMI, Ca2+, biochemical indicators (UA, Cr, CysC, and Hcy), inflammation index (WBC, NEUT, LY, neutrophil–lymphocyte ratio [NLR], and CRP), renal function index (eGFR, ACR, MAU, α-MG, Tf, and Ig), blood lipid (TC,TG,LDL, and HDL), HbA1c, FPG, 1Hpbg, 2hPBG, 3hPBG, insulin (fasting and postprandial respectively 1, 2, and 3 h), C-peptide (fasting and postprandial 2 h), HOMA-IR, VPT, CPT,TCSS.
Data statistics and analysis methods
SPSS 20.0 statistical software was used for data analysis. Statistical charts were made by GraphPad Prism and SPSS 20.0 statistical software. P < 0.05 and P < 0.01 were considered statistically significant. (n = 79)