Energy Metabolism in Thyroidectomized Patients

The purpose of this research study is to measure the changes in energy metabolism (how the body burns energy), cardiovascular function (heart function), and lipid metabolism (cholesterol break down and building) before and after thyroidectomy (surgical removal of thyroid gland) in response to two approved therapies for hypothyroidism: levothyroxine (LT4) or Liothyronine/levothyroxine (LT3/LT4) combination therapy.

In this study, Levothyroxine (LT4) and placebo (a look-alike inactive substance, a "sugar pill") will be compared to Liothyronine/ Levothyroxine (LT3/LT4) combination therapy. Levothyroxine LT4 and Liothyronine (LT3) are drugs approved by the U. S. Food and Drug Administration (FDA). All participants will be required follow VCU Health COVID-19 standard of Care screening procedures. This study requires approximately five study visits The five-study visits required will be a Screening Visit (outpatient), one Baseline Visit, (inpatient) one Six Week Visit, (outpatient), one Three Month Visit and one Six Month Visit (both inpatient). A COVID-19 test will be done 48 hours (2 days) before each of the three-inpatient visit, Baseline Visit, Three Month and Six Month Visit. Participants will be asked to: Give permission for the researchers to collect information about their medical history from participants and their medical records five times during the study visits and for 5 years after the study visits. Have a Physical exam done 5 times 24-hour energy expenditure recording in the Whole room indirect calorimeter studies 3 times (inpatient overnight stays: Baseline, Three months, and Six months visits) Study drug will be dispensed three times Have study drug dose adjustments two times Genomic blood draw for DNA one time Have blood drawn five times Have an DXA Scan two times Have an Echocardiogram three times Complete questionnaire three times Have Accelerometers sensors laced 3 times (inpatient overnight stays: Baseline, Three months, and Six months visits) ClearSight (blood pressure monitoring) procedure three times Be randomized to take either Levothyroxine LT4 + placebo group or LevothyroxineLT3/Liothyronine LT4 group from baseline through 6 months Participation in this study will last up to 6 months after surgery. Approximately 30 total individuals will participate in this study

Levothyroxine (LT4) and placebo (a look-alike inactive substance, a "sugar pill") Patients in the LT4 group will be started at a dose of 1.6 mcg/Kg (52 The VCU Investigational Pharmacy will over-encapsulate LT4 plus placebo, in "AM" and "PM" color coded capsules. Patients will be instructed to take the AM drug first thing in the morning with water only, and to wait at least 30 minutes before taking other medications coffee or breakfast. The PM dose will be taken at least 30 minutes before dinner. Dose adjustments will be performed at the 6-week and 3-month follow up visits by an unblinded endocrinologist (Dr. Yavuz) aiming to achieve and maintain a target TSH within the normal range and within ± 0.5 mcIU/ml from the baseline (pre-surgery) TSH, Doses will be rounded to the nearest available formulation.

Liothyronine/levothyroxine (LT3/LT4) combination therapy. LT4/LT3 group will have 25 mcg of LT4 substituted with 5 mcg LT3 twice daily, to mimic the average daily T3 production form the thyroid The VCU Investigational Pharmacy will over-encapsulate LT4 plus 5 mcg LT3 in "AM" and "PM" color coded capsules. Patients will be instructed to take the AM drug first thing in the morning with water only, and to wait at least 30 minutes before taking other medications coffee or breakfast. The PM dose will be taken at least 30 minutes before dinner. Dose adjustments will be performed at the 6-week and 3-month follow up visits by an unblinded endocrinologist (Dr. Yavuz) aiming to achieve and maintain a target TSH within the normal range and within ± 0.5 mcIU/ml from the baseline (pre-surgery) TSH, Doses will be rounded to the nearest available formulation. No changes will be made in LT3.

Inclusion Criteria: Clinical indication for total thyroidectomy TSH at screening >0.045<4.5mlU/m Adult men and women Age ≥18-89 years of age Euthyroid patients with clinical indication for total thyroidectomy Indication to total thyroidectomy for benign goiter or thyroid cancer not requiring suppressive thyroid hormone therapy Exclusion Criteria: Weight <50 or >150 Kg Graves' disease Use of thyroid hormone therapy or thyroid supplements (at screening) except for multinodular goiter Indication for thyroid hormone suppressive therapy following surgery Uncontrolled arterial hypertension stage 2 or greater (>140/90 mm Hg at screening) while on medication (patients with hypertension controlled by therapy will be allowed to participate). Uncontrolled diabetes (HbA1c > 8.% at screening or Fructosamine > 325 mmol/L) History of cardiovascular disease, congestive heart failure or unstable coronary artery disease (angina, coronary event, or revascularization within 6 months); atrial fibrillation; or ventricular arrhythmia, History of major depression or psychosis Patients who are Pregnant, breastfeeding planned pregnancy within six months from the thyroidectomy Any conditions that in the opinion of the PI may impede the successful completion of the study