Abstract: Objective To study the relationship between serum ferritin(SF), C-reactive protein (CRP) and carotid intima-media thickness (CIMT) in the elderly patients with subclinical hypothyroidism (SCH) combined with type 2 diabetes mellitus (T2DM), and to analyze the influencing factors of CIMT thickening. Methods From January 2018 to January 2020, seventy-eight elderly patients with SCH complicated with T2DM were selected as the disease group, and the patients with only SCH (SCH group) or T2DM (T2DM group) matched by age and gender were selected as controls. The levels of SF and CRP of all the subjects were detected, and CIMT was detected by carotid ultrasound. The levels of SF, CRP and CIMT were compared between the three groups. Pearson correlation analysis was used to analyze the correlation between SF, CRP and CIMT. Univariate and multivariate Logistic regression analysis was used to evaluate the risk factors of CIMT thickening in the elderly patients with SCH combined with T2DM. Results The levels of SF, CRP and CIMT of the disease group were higher than those of SCH group and T2DM group(P<0.001).There were no statistically significant differences between SCH group and T2DM group in the levels of SF, CRP and CIMT(P＞0.05). Pearson correlation analysis showed that the levels of SF and CRP in the disease group were positively correlated with CIMT (P<0.05). Univariate analysis showed that the levels of SF, CRP, low density lipoprotein (LDL-C), total cholesterol (TC), thyroid stimulating hormone (TSH) and hypertension history in the CIMT thickening group were higher than those in the normal group, while the level of HDL-C in the thickening group was lower than that in the normal group (P<0.05). Logistic regression analysis showed that SF, CRP, LDL-C and TC were risk factors for CIMT thickening in the elderly patients with SCH combined with T2DM, and HDL-C was a protective factor (P<0.05). Conclusions The levels of SF, CRP and CIMT are increased in the elderly patients with SCH combined with T2DM, and SF and CRP are the influencing factors of CIMT thickening in the elderly patients with SCH and T2DM.

Key words: subclinical hypothyroidism, type 2 diabetes mellitus, carotid intima-media thickness, atherosclerosis