Baseline clinical and biochemical characteristics
The clinical and biochemical characteristics of the participants are shown in Table 1. A total of 1444 patients with T2D with a mean age of 58.8 ± 13.0 years were enrolled in this study. The overall prevalence of TNs was 45.6%. Then, the subjects were divided into two groups including TNs (with TNs) group and NTNs (without TNs) group, and the level of each variable was compared between the two groups (Table 1). The results showed that the age, duration of diabetes, SBP, HDL-c, FT3, and the percentage of female, DR and PAS were significantly increased, and the TG / HDL-c ratio, UA, Scr, UMA and the percentage of smoking, DN were significantly decreased in the TNs group (all P-value < 0.05). However, there was no obvious differences in the drinking, BMI, DBP, age of menarche, age of menopause, TC, LDL-c, TG, HbA1c, ALT, AST, UACR, Hb, FT4, TSH, TPOAb, Ca, Mg, P, and the percentage of DPN between the two groups (all P-value > 0.05).
Correlation between TNs and all variables by univariate analysis
As shown in Table 2, a spearman correlation analysis was performed to analyze the relationship between TNs and each variable. The results showed that TNs was related positively to sex (female), age, duration of diabetes, SBP, HDL-c, FT3, Mg, DR and PAS (all P-value < 0.05), while negatively to smoking, TG/HDL-c ratio, UA, Scr, UMA, Hb and DN (all P-value < 0.05). However, there was no significant association between TNs and drinking, BMI, DBP, age of menarche, age of menopause, TC, LDL-c, TG, HbA1c, ALT, AST, UACR, FT4, TSH, TPOAb, Ca, P and DPN in all patients (all P-value > 0.05).
Subsequently, stratified by sex and age, the results displayed that the duration of diabetes, FT3, Ca, DR and PAS were positively, and the UACR and UMA were negatively related to TNs in female (all P-value < 0.05), while the age, SBP, Mg, DR and PAS were positively, and the TG/HDL-c, AST, and UA were negatively related to TNs in male (all P-value < 0.05). Additionally, the sex (female), age, DR and PAS were positively, and the smoking, UA, Scr and Hb were negatively related to TNs in patients below 60 years old (all P-value < 0.05), while the sex (female), HDL-c, FT3, Ca, Mg and PAS were positively, and the UMA and DN were negatively related to TNs in patients over 60 years old (all P-value < 0.05).
Independent correlates of TNs by logistic regression analysis
Firstly, in the overall population, TNs was served as the dependent variable, and the sex, age, duration of diabetes, smoking, SBP, HDL-c, TG/HDL-c ratio, UA, Scr, UMA, Hb, FT3, Mg, DN, DR and PAS were as the independent variables according to the results of univariate analysis (Table 1 and Table 2). A logistic regression analysis was performed to analyze the independent correlates of TNs (Table 3), and the results found that after adjusting for the other variables, the sex (female), age, FT3 and PAS was significantly positively related to TNs (all P-value < 0.05), while the UA was independently and negatively related to TNs (P-value = 0.046). Subsequently, stratified by sex and age, the results displayed that the FT3, PAS and duration of diabetes adjusting for the UACR, UMA, Ca and DR in female, while the age and PAS adjusting for the SBP, TG/HDL-c, AST, UA, Mg and DR in male, was significantly related to TNs (all P-value < 0.05). Besides, the age and female adjusting for the smoking, UA, Scr, Hb, DR and PAS in patients below 60 years old while the female, PAS, FT3 and Mg adjusting for the HDL-c, UMA, Ca and DN in patients over 60 years old, was closely related to TNs (all P-value < 0.05).