Variations in the DIO2 and MCT10 Genes and Effect of Triiodothyronine Treatment

Overview

Hypothesis: Variations in the deiodinase 2 gene and monocarboxylate transporter 10 gene is associated with improvement in quality of life after initiation of combination therapy with L-Thyroxine and Liothyronine in patients with persistent hypothyroid symptoms despite conventional L-thyroxine mono-therapy.

Purpose: To re-test this hypothesis in patients with continued perceived effect of Liothyronine treatment at least one year after initiation in a patient population more representing of daily clinical practice. The study will help determine whether testing of specific gene variations might predict longtime effect of combination therapy.

Full Title of Study: “Longtime Effect of Combination Treatment With L-thyroxine (L-T4) and Liothyronine (L-T3) in Patients With Persistent Hypothyroid Symptoms – Relation to Polymorphisms (SNP) in the DIO2 and the MCT10 Gene”

Study Type

  • Study Type: Observational
  • Study Design
    • Time Perspective: Cross-Sectional
  • Study Primary Completion Date: April 2021

Arms, Groups and Cohorts

  • Responders
    • Patients in combination therapy due to persistent symptoms on L-thyroxin mono-therapy who experience a longtime effect of triiodothyronine treatment.
  • Non-responders
    • Patients who have tried combination therapy due to persistent symptoms on L-thyroxin mono-therapy, but did not experience a longtime effect.

Clinical Trial Outcome Measures

Primary Measures

  • Polymorphisms in DIO2/MCT10 and triiodothyronine treatment
    • Time Frame: Single assessment point, from 1-10 years after initiation of combination therapy
    • Group 1(responders) and group 2(non-responders) are compared with regard to polymorphisms in the DIO2 gene and the MCT10 gene. Polymorphisms will be determined from DNA in a blood sample

Secondary Measures

  • Proportion treated with triiodothyronine
    • Time Frame: Single assessment point, from 1-10 years after initiation of combination therapy
    • How many patients are treated with triiodothyronine at least one year after initiation of combination therapy.
  • Quality of life questionnaire
    • Time Frame: Single assessment point, from 1-10 years after initiation of combination therapy
    • Patients are scored on the ThyPRO questionnaire and a hypothyroid symptoms questionnaire.
  • Who controls the treatment?
    • Time Frame: Single assessment point, from 1-10 years after initiation of combination therapy
    • Patients report whether treatment is controlled by 1) a general practitioner 2) Patient self 3) other type of healthcare professional 4) a certified endocrinologist or 5) other
  • How is current treatment controlled?
    • Time Frame: Single assessment point, from 1-10 years after initiation of combination therapy
    • Patients report if current treatment is for example controlled by using blood samples or only on the basis of symptoms.
  • Have therapy changed after the patient left the department of endocrinology?
    • Time Frame: Single assessment point, from 1-10 years after initiation of combination therapy
    • Current hypothyroidism treatment and doses of medication
  • TSH
    • Time Frame: Single assessment point, from 1-10 years after initiation of combination therapy
    • Is the patient well regulated? Normal TSH: 0.1-4.0 (depending on assay used). Over-treatment: TSH < 0.1 (depending on assay used). Under-treatment: TSH>4 (depending on assay used).
  • Osteoporosis
    • Time Frame: Single assessment point, from 1-10 years after initiation of combination therapy
    • DXA-scan
  • Risk of arrhythmia
    • Time Frame: Single assessment point, from 1-10 years after initiation of combination therapy
    • Puls and blood pressure is measured. If arrhythmia is suspected, an ECG is performed.

Participating in This Clinical Trial

Inclusion Criteria

  • Patients admitted to the department of endocrinology with the diagnose hypothyroidism because of persistent hypothyroid symptoms despite treatment with L-thyroxine mono-therapy and normal and stable TSH (for at least 6 months).
  • Started in combination therapy with L-thyroxine and Liothyronine in an approximately 17/1 ratio
  • Exclusion of an alternative explanation for persistent hypothyroid symptoms

Exclusion Criteria

  • Initiation of L-thyroxine treatment in patients with s-TSH below upper normal limit (with assay in current use, that is TSH < 4 mU/L)
  • Ongoing pregnancy
  • Age below 18 years or above 80 years.
  • Patients who do not read and understand information material given
  • Patients who are not competent to give informed consent

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 80 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Birte Nygaard
  • Provider of Information About this Clinical Study
    • Sponsor-Investigator: Birte Nygaard, Chief Physician, Ph.D – Herlev Hospital
  • Overall Official(s)
    • Birte Nygaard, Ph.D., Principal Investigator, Herlev Hospital
  • Overall Contact(s)
    • Christian Z Jensen, MD, 52652688, christian.zinck.jensen.01@regionh.dk

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