2.2 Study protocol
In addition to determining the association between SCH and carotid intima-media thickness, we studied the influence of levothyroxine hormone replacement at short- and long-term follow up on carotid intima-media thickness, as a secondary endpoint. We also evaluated the correlation between the carotid intima-media thickness and age, body mass index (BMI), waist circumference, waist-hip ratio (WHR), systolic and diastolic arterial pressure (BP), level of anti-thyroid peroxidase antibodies (anti-TPO), fasting glycemia, and lipid levels.
A blood sample for a biochemical profile, thyroid hormone levels, anti-TPO, and a lipid profile was obtained in all participants. On physical examination, a particular emphasis was given to weight, height, body mass index (BMI), antrophometric measures, and blood pressure. Carotid assessment by ultrasound included the intima-media thickness of the right common carotid artery (RCCA) and the left common carotid artery (LCCA). After the baseline assessment, thyroid hormone replacement was started in PH and PSH participants. In PSH participants, a carotid assessment follow-up was carried out 3 and 6 months after the baseline visit. Complete blood sampling and physical examination, as in the first visit, were repeated in this group at 3 and 6 months.