Background  At present, the number of patients with type 2 diabetes mellitus (T2DM) is constantly increasing, and T2DM has become a public health problem worldwide. Early intervention for patients with prediabetes can significantly reduce the risk of T2DM, therefore, it is necessary to identify the high-risk population as early as possible and search for objective indicators for the evaluation and early warning of prediabetes.

  Objective  To investigate the changes in serum thioredoxin (TRX) and asprosin (Asp) in patients with prediabetes or T2DM and related influencing factors.

  Methods  A total of 155 patients who attended the outpatient service of Department of Endocrinology in Baoding First Central Hospital from December 2018 to January 2020 were enrolled as subjects, among whom there were 51 patients with impaired fasting glucose (IFG group), 54 patients with impaired glucose tolerance (IGT group), 50 patients with T2DM (DM group), and another 42 subjects with normal glucose tolerance during the same period of time were enrolled as control group (NGT group). The 75 g oral glucose tolerance test was performed for all subjects, and related indice were compared between groups. ELISA was used to measure the serum levels of TRX and Asp, and Spearman correlation analysis and multiple linear regression analysis were used to investigate the influencing factors for serum TRX and Asp.

  Results  The NGT group had the highest serum TRX concentration of 5.01±0.71 ng/mL, followed by the IFG group (4.59±0.78 ng/mL), the IGT group (4.24±0.71 ng/mL), and the DM group (3.90±1.00 ng/mL), and there were significant differences between groups (all P <0.05); the DM group had the highest serum Asp concentration of 6.27±0.76 ng/mL, followed by the IGT group (5.37±1.63 ng/mL), the IFG group (4.71±1.10 ng/mL), and the NGT group (4.05±0.75 ng/mL), with significant differences between groups (P<0.05). The Spearman correlation analysis showed that serum TRX concentration was negatively correlated with systolic blood pressure (SBP), total cholesterol (TC), triglyceride (TG), low-density lipoprotein, fasting blood glucose (FBG), 120-minute postprandial blood glucose (PBG) in glucose tolerance test, glycosylated hemoglobin (HbA1c), fasting insulin (FINS), Homeostasis Model Assessment of Insulin Resistance (HOMA-IR), and Asp (all P<0.01) and was positively correlated with high-density lipoprotein (P<0.01). The serum Asp concentration was positively correlated with SBP, TC, TG, FBG, PBG, HbA1c, FINS, and HOMA-IR (all P<0.01) and was negatively correlated with serum TRX (P<0.01). The multiple linear regression analysis showed that FBG, FINS, HOMA-IR, and Asp were independently associated with serum TRX (all P<0.05), and FBG, TC, FINS, and HOMA-IR were independently associated with serum Asp (all P <0.05).

  Conclusion  Patients with diabetes or prediabetes have a lower serum level of TRX and a higher serum level of Asp than the population with normal glucose tolerance, suggesting that serum TRX and Asp may be involved in disease progression in patients with prediabetes, which is of important reference value for the timely diagnosis and treatment of prediabetes and diabetes.