Efficacy and safety of LT4 monotherapy in lowering the risk of cardiovascular disease in older adults with subclinical hypothyroidism: research protocols of a multi-center, open label, randomized controlled trial

Objective This multicenter, open-label, randomized-controlled trail (RCT) aims to assess the efficacy and safety of levothyroxine (LT4) monotherapy in lowering the risk of cardiovascular disease (CVD) in untreated older adults with subclinical hypothyroidism (SCH) diagnosed by population-specific TSH reference values. Methods A total of 230 patients with SCH who meet the diagnostic criteria are recruited, and the baseline clinical data of the patients are collected. Then, 115 cases are randomly divided into treatment group and control group, and the treatment group is treated with LT4 (Ujiale) 50 microgram tablet (Merck, Germany) on the basis of the control group, and the specific method is to give 50 micrograms (body weight) per day< 50 kg to 25 micrograms) for at least 48 weeks to maintain thyroid-stimulating hormone (TSH) within the normal range. The thyroid status of participants in the control group will only be reviewed and recorded. Participants complete five visits before and after the start of the trial to evaluate the difference in carotid intima-media thickness (CIMT) change and maximum plaque change mean and lipid profile, bone mineral density, and incidence of fatal and non-fatal cardiovascular events between the last follow-up and the initial follow-up by vascular ultrasound. Discussion Our findings are expected to provide scientific references for precise diagnosis and treatment of SCH in older adults. [Clinical trial registration] Clinical Trials.gov, No. ChiCTR2400092634. Registered on 30 November 2024. Recruitment for this study will begin on December 1, 2024 and continue until at least November 30, 2025.