The Relationship Between Serum rT3 Concentrations, T3/T4 Ratio, and Symptoms/Quality of Life in Treated Hypothyroid Patients

Launched by SEMMELWEIS UNIVERSITY · Aug 16, 2021

Keywords

ClinConnect Summary

Rationale: L-thyroxin (T4) substitution is the mainstay of treatment for hypothyroidism irrespective of disease origin. In a subset of patients with hypothyroidism however an inadequate peripheral T4-\>T3 conversion is hypostasized by some authors. This is speculated to lead to tissue level hypothyroidism and persistent symptoms even with adequate T4 replacement. As a potential pathogenetic mechanism, the inborn or acquired defect of peripheral deiodinases, decreased T3 and increased rT3 production is suggested.

Few results support this hypothesis. A decreased T3/T4 ratio has been reported...

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Eligibility criteria

• Inclusion Criteria:
• • At least 18 years of age, inclusive, at the time of signing informed consent form.
• • Hypothyroidism treated for \>2 years
• • TSH stable between 0.4 and 4.0 mIU/L for the past 6 months (at least 2 measurements)
• Exclusion Criteria:
• • Abnormal TSH on screening
• • Unwilling or unable to participate/sign informed consent
• • Changes in thyroxine dose or any other medication in the previous month
• • Severe obesity (BMI \[body mass index\] \>35kg/m2)
• * Other significant comorbidity:
• • History of ischaemic heart disease, valvular defect, stent placement, heart failure, stroke or TIA (transient ischemic attack)
• • Diabetes mellitus under OAD (oral antidiabetic drug) or insulin treatment
• • eGFR (estimated glomerular filtration rate) \<60ml/min at screening, calculated by EPI formula
• • History of liver disease, AST/ALT\>3 times normal or GGT (gamma-glutamil transferase) \>2 times normal or hyperbilirubinaemia at screening
• • Systemic autoimmune condition currently under treatment (RA \[rheumatoid arthritis\], lupus, systemic sclerosis etc.)
• • Active malignancy