AIM: To study the time course changes in the parameters of endothelial 
dysfunction in patients with type 2 diabetes mellitus (DM) and subclinical 
hypothyroidism (SH) in the natural course of SH and during replacement therapy.
SUBJECTS AND METHODS: All the examined patients were divided into 2 groups: 1) 
67 patients received replacement therapy with euthyrox in a dose of 25 to 100 
microg/day; 2) 60 patients were followed up.
RESULTS: At the moment of study inclusion, there was a close direct correlation 
between the levels of cholesterol and the aggregate intima-media thickness (IMT) 
(r = 0.7) and between IMT and the levels of sICAM-1 (r = 0.71) and sVCAM-1 (r = 
0.8). In the dynamics of the disease (following a year), the above correlations 
became weaker due to the performed treatment. A weak positive correlation was 
found between the aggregate IMT and the levels of sICAM-1 (r = 0.2) and sVCAM-1 
(r = 0.3).
CONCLUSION: In patients with type 2 DM, the presence of SH serves as an 
additional risk factor for endothelial dysfunction. Replacement therapy will be 
able to considerably retard the progression of the disease and to reduce the 
incidence of vascular events.