HypothyroidismPhase 4NCT00565864
Neurocognitive and Metabolic Effects of Mild Hypothyroidism
A Phase 4 study testing L-thyroxine (L-T4) in people with Hypothyroidism, run by Oregon Health and Science University at 1 site in United States.
Trial summary
Patients with hypothyroidism are routinely treated with thyroid hormone (l-thyroxine) for replacement therapy. Physicians monitor the thyroid hormone dose by measuring a thyroid stimulating hormone (TSH) level in the blood, with the goal of a normal level. Read more about this study
- Who is it for?
- Ages 20 to 75 years
- Conditions the study is for
- Hypothyroidism
- What is being tested?
- L-thyroxine (L-T4)
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 173 participants
- Where
- 1 siteUnited States
- Study dates
- Aug 2008to Aug 2013
- Phase
- Phase 4
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 20 to 75 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Ages 20-75
- Primary hypothyroidism on stable dose of L-T4 for > 3 months
- Documented elevated TSH off L-T4
- Normal TSH level on usual dose of L-T4
- No acute or chronic medical or psychiatric illnesses that affect thyroid function, mood or cognition
- No medication use that affects thyroid function, mood or cognition (oral contraceptives or estrogen therapy allowed)
Show all 10Show fewer
- Normal score on screening Mini-Mental State Exam (MMSE) (to test for dementia)
- Normal vision by screening examination
- Normal hearing by screening examination
- Non smoker
Who cannot join
- Failure to meet any of the above inclusion criteria
- Inability to speak and comprehend English
- A history of coronary artery disease
- Screening hgb <10
- Screening wbc > 10,000
- Clinically significant abnormalities on screening metabolic set
Show all 12Show fewer
- Screening LDL cholesterol > 160
- Screening triglyceride > 300
- Significant abnormalities on screening ECG
- Pregnancy or intent to become pregnant in next 6 months
- Present or recent use of medications that affect thyroid hormone levels or interfere with thyroid hormone effects, including beta-blockers, lithium, glucocorticoids, or iodine containing agents
- MMSE score < 26
Trial locations and contacts
1 site in 1 country.
United States1 site
Oregon Health and Science University
Portland, Oregon, 97201
About this study
Patients with hypothyroidism are routinely treated with thyroid hormone (l-thyroxine) for replacement therapy. Physicians monitor the thyroid hormone dose by measuring a thyroid stimulating hormone (TSH) level in the blood, with the goal of a normal level. However, recent data suggest that the "normal" TSH range is too broad, and that patients may still have symptoms if their TSH levels are at the top or bottom part of the normal range.
To study this issue, it is useful to address issues such as general health status, psychological symptoms, mood, memory, and metabolic status, since thyroid hormone has major effects on the brain and metabolism, and since patients with treated hypothyroidism often have symptoms related to these areas.
Read more
In the present study, otherwise healthy subjects with treated hypothyroidism, ages 20-75 years, will be enrolled in a 7-11month study. At baseline, they will have tests of health status, psychological symptoms, mood, memory, body composition, and energy expenditure performed. Following these baseline measurements, subjects will receive either their usual doses of l-thyroxine, or a slightly higher or lower dose. The doses will be chosen to try to achieve either a low-normal TSH level, a high-normal TSH level, or a mildly elevated TSH level. Which target TSH the patient is assigned will be determined randomly, and neither the subject nor the study contacts will know which dose the patient is receiving. Subjects will be seen every 6 weeks during the study for brief visits to make sure they are not having any side effects, and to adjust the l-thyroxine doses if the TSH has not yet reached the target range. At the 24-week visit (end of study), the subjects will undergo the same tests that they had on the baseline visit.
Results from the study will be examined to see if minor changes in TSH or other thyroid hormone levels cause changes in any of the outcomes, and if the degree of TSH change correlates with the degree of outcome changes. These results may help physicians caring for patients with thyroid disease better determine the optimal dose of thyroid hormone for each patient.
Read the detailed description
Thyroid hormone is essential for neurocognitive and metabolic function, and patients with overt thyroid dysfunction have well-described alterations in mood, cognition, energy expenditure, and body composition. However, it is not clear that patients with more mild degrees of thyroid dysfunction have clinically significant alterations in these parameters.
In addition, recent data suggest that variations in thyroid function within the laboratory reference range may also affect these parameters.
Patients with hypothyroidism are routinely treated with levothyroxine (L-T4) as replacement therapy. Physicians monitor the L-T4 dose by measuring serum thyroid stimulating hormone (TSH) levels, with the goal of a normal level. However, many patients with normal TSH levels continue to report symptoms, primarily in neurocognitive and metabolic areas. For this reason, patients with hypothyroidism often request higher L-T4 doses, but the clinical consequences of this are unknown.
In the present study, otherwise healthy subjects with treated hypothyroidism and normal TSH levels, ages 20-75 years, will be enrolled in a 7-11 month study. At baseline, the following tests will be performed to measure health status, psychological symptoms, mood, memory, body composition, and energy expenditure: the Short Form Health Survey-36 (SF-36), Profile of Mood States (POMS), Affective Lability Scale (ALS), Letter Cancellation Test (LCT), Trail Making Test, Iowa Gambling Task (IGT), N-Back Test, Subject-Ordered Pointing, Paragraph Recall, Pursuit Rotor, Motor Sequence Learning Test, resting energy expenditure (REE) and thermic effect of food (TEF) by indirect calorimetry, total energy expenditure (TEE) by doubly labelled water, physical activity energy expenditure (PAEE) by accelerometry, diet intake by 24-hour diet recalls, and body composition by dual energy x-ray absorptiometry (DEXA). Following these baseline measurements, subjects will receive either their usual doses of L-T4, or a slightly higher or lower dose. The doses will be chosen to try to achieve either a low-normal TSH level, a high-normal TSH level, or a mildly elevated TSH level. Which target TSH the patient is assigned will be determined randomly, and neither the subject nor the study contacts will know which dose the patient is receiving. Subjects will be seen every 6 weeks during the study for brief visits to make sure they are not having any side effects, and to adjust L-T4 doses if the TSH has not yet reached the target range. At the 24-week visit (end of study), the subjects will undergo the same tests that they had on the baseline visit.
Results from the study will be examined to see if minor changes in TSH or other thyroid hormone levels cause changes in any of the outcomes, and if the degree of TSH change correlates with the degree of outcome changes. These results may help physicians caring for patients with thyroid disease better determine the optimal dose of thyroid hormone for each patient.
- Conditions
- Hypothyroidism
- Being tested
- L-thyroxine (L-T4)
- Keywords
- Hypothyroidism, Cognition, Metabolism
- Medical subject headings
- Hypothyroidism
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
L-thyroxine (L-T4)Drug
Also called Subjects will remain on their usual brand of L-T4., Subjects on generic L-T4 will be switched to Levoxyl.
L-thyroxine (L-T4) is the intervention for each arm/group. In each arm/group, the dose of L-T4 is adjusted to achieve TSH levels in the randomly assigned arm. L-thyroxine at doses appropriate to attain target TSH levels for the different arms for 24 weeks
| Study group | Role | What they receive |
|---|---|---|
| 1 (Low-normal TSH target) | Experimental | Treatment arm 1 targets a thyroid stimulating hormone (TSH) of 0.28 -2.49 milliunits/liter (mU/L) (the theoretical optimal range). The intervention is as follows: Levothyroxine (L-T4) doses will be adjusted in this arm to achieve this target TSH range. L-T4 is the intervention. L-T4 is given once per day, in the morning, while fasted. Dose ranges for the study are calculated based on each subject's TSH levels monitored during the study. Duration of the intervention is the duration of the study, after which subjects return to taking their usual L-T4 doses. Receives: Drug: L-thyroxine (L-T4) |
| 2 (High-normal TSH target) | Experimental | Treatment arm 2 targeting a TSH of 2.5 - 5.0 mU/L. The intervention is as follows:
Levothyroxine (L-T4) doses will be adjusted in this arm to achieve this target TSH range. L-T4 is the intervention. L-T4 is given once per day, in the morning, while fasted. Dose ranges for the study are calculated based on each subject's TSH levels monitored during the study. Duration of the intervention is the duration of the study, after which subjects return to taking their usual L-T4 doses. Receives: Drug: L-thyroxine (L-T4) |
| 3 (Mildly elevated TSH target) | Experimental | Treatment arm 3 is targeting a TSH level o f 5.1-12.0 mU/L. The intervention is as follows:
Levothyroxine (L-T4) doses will be adjusted in this arm to achieve this target TSH range. L-T4 is the intervention. L-T4 is given once per day, in the morning, while fasted. Dose ranges for the study are calculated based on each subject's TSH levels monitored during the study. Duration of the intervention is the duration of the study, after which subjects return to taking their usual L-T4 doses. Receives: Drug: L-thyroxine (L-T4) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Executive Function
Iowa Gambling Task Net-5. Four decks of cards are shown face down on a computer screen. The subject chooses cards from any deck, resulting in the gain or loss of money. The subject is unaware that 2 decks are advantageous (small gains, smaller losses), while 2 are disadvantageous (large gains, larger losses). The subject's choices are classified as advantageous (X) or disadvantageous (Y), with a net score of X-Y, over 5 trials of 100 cards each. The outcome reported here is the score on the fifth trial, which is generally the best trial due to practice effects. The minimum score is -20 and the maximum score is +20. Higher scores indicate a better outcome.
Measured: 24 weeks
Resting Energy Expenditure
Measurement of resting energy expenditure (REE) by indirect calorimetry, corrected for lean body mass. Indirect calorimetry is performed at 21.1° C after the participant has fasted for 12h and abstains from significant physical activity for 24h. The indirect calorimeter (VMax Encore 29N Indirect Calorimeter, SensorMedics Viasys Healthcare, Yorba Linda, CA) samples expired air and analyzes it for the volume of oxygen consumed (VO2) and the volume of carbon dioxide produced (VCO2) each minute for 30mins. REE is then calculated using the modified Weir equation. Minimum REE is 23 kcal/kg LBM/day and maximum REE is 39 kcal/kg LBM/day. Within that range, higher levels are considered better for the purposes of this study.
Measured: 24 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Nov 2007 (estimated)
- Study startAug 2008
- Primary completionAug 2013
- Study completionAug 2013
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (6)Papers the sponsor has linked to this study.
- Other trials for HypothyroidismStudies of the same condition, open and under way.
- More trials run by Oregon Health and Science UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 173 participants (actual)
Sponsor and investigators
- Lead sponsor
- Oregon Health and Science University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Mary Samuels, Oregon Health and Science University
- Investigators
- Mary Samuels, MD, Principal investigator, Oregon Health and Science University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00565864
- Sponsor's protocol ID
- IRB00002265
- Status last verified
- Aug 2018
- First submitted
- 28 Nov 2007
- Last updated
- 22 Aug 2018
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
Publications
Samuels MH, Kolobova I, Niederhausen M, Purnell JQ, Schuff KG. Effects of Altering Levothyroxine Dose on Energy Expenditure and Body Composition in Subjects Treated With LT4. J Clin Endocrinol Metab. 2018 Nov 1;103(11):4163-4175. doi: 10.1210/jc.2018-01203.
PubMed 30165520Samuels MH, Kolobova I, Niederhausen M, Janowsky JS, Schuff KG. Effects of Altering Levothyroxine (L-T4) Doses on Quality of Life, Mood, and Cognition in L-T4 Treated Subjects. J Clin Endocrinol Metab. 2018 May 1;103(5):1997-2008. doi: 10.1210/jc.2017-02668.
PubMed 29509918Samuels MH, Kolobova I, Antosik M, Niederhausen M, Purnell JQ, Schuff KG. Thyroid Function Variation in the Normal Range, Energy Expenditure, and Body Composition in L-T4-Treated Subjects. J Clin Endocrinol Metab. 2017 Jul 1;102(7):2533-2542. doi: 10.1210/jc.2017-00224.
PubMed 28460140Samuels MH, Kolobova I, Smeraglio A, Niederhausen M, Janowsky JS, Schuff KG. Effect of Thyroid Function Variations Within the Laboratory Reference Range on Health Status, Mood, and Cognition in Levothyroxine-Treated Subjects. Thyroid. 2016 Sep;26(9):1173-84. doi: 10.1089/thy.2016.0141. Epub 2016 Jul 25.
PubMed 27338133Samuels MH, Kolobova I, Smeraglio A, Peters D, Purnell JQ, Schuff KG. Effects of Levothyroxine Replacement or Suppressive Therapy on Energy Expenditure and Body Composition. Thyroid. 2016 Mar;26(3):347-55. doi: 10.1089/thy.2015.0345. Epub 2016 Feb 3.
PubMed 26700485Samuels MH, Kolobova I, Smeraglio A, Peters D, Janowsky JS, Schuff KG. The effects of levothyroxine replacement or suppressive therapy on health status, mood, and cognition. J Clin Endocrinol Metab. 2014 Mar;99(3):843-51. doi: 10.1210/jc.2013-3686. Epub 2014 Jan 13.
PubMed 24423358
Study at a glance
From the registry record, last updated by the sponsor on 22 Aug 2018. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Neurocognitive and Metabolic Effects of Mild Hypothyroidism
- ClinicalTrials.gov ID
- NCT00565864
- Acronym / sponsor ID
- IRB00002265
- Conditions
- Hypothyroidism
- Keywords
- Hypothyroidism, Cognition, Metabolism
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 173 participants (actual)
- Lead sponsor
- Oregon Health and Science UniversityUniversity, hospital or other
- Study start
- Aug 2008
- Primary completion
- Aug 2013 (actual)
- Study completion
- Aug 2013 (actual)
- First posted
- 30 Nov 2007 (estimated)
- Results
- Posted 22 Aug 2018
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Patients with hypothyroidism are routinely treated with thyroid hormone (l-thyroxine) for replacement therapy. Physicians monitor the thyroid hormone dose by measuring a thyroid stimulating hormone (TSH) level in the blood, with the goal of a normal level. However, recent data suggest that the "normal" TSH range is too broad, and that patients may still have symptoms if their TSH levels are at the top or bottom part of the normal range.
To study this issue, it is useful to address issues such as general health status, psychological symptoms, mood, memory, and metabolic status, since thyroid hormone has major effects on the brain and metabolism, and since patients with treated hypothyroidism often have symptoms related to these areas.
In the present study, otherwise healthy subjects with treated hypothyroidism, ages 20-75 years, will be enrolled in a 7-11month study. At baseline, they will have tests of health status, psychological symptoms, mood, memory, body composition, and energy expenditure performed. Following these baseline measurements, subjects will receive either their usual doses of l-thyroxine, or a slightly higher or lower dose. The doses will be chosen to try to achieve either a low-normal TSH level, a high-normal TSH level, or a mildly elevated TSH level. Which target TSH the patient is assigned will be determined randomly, and neither the subject nor the study contacts will know which dose the patient is receiving. Subjects will be seen every 6 weeks during the study for brief visits to make sure they are not having any side effects, and to adjust the l-thyroxine doses if the TSH has not yet reached the target range. At the 24-week visit (end of study), the subjects will undergo the same tests that they had on the baseline visit.
Results from the study will be examined to see if minor changes in TSH or other thyroid hormone levels cause changes in any of the outcomes, and if the degree of TSH change correlates with the degree of outcome changes. These results may help physicians caring for patients with thyroid disease better determine the optimal dose of thyroid hormone for each patient.
Detailed description
Thyroid hormone is essential for neurocognitive and metabolic function, and patients with overt thyroid dysfunction have well-described alterations in mood, cognition, energy expenditure, and body composition. However, it is not clear that patients with more mild degrees of thyroid dysfunction have clinically significant alterations in these parameters.
In addition, recent data suggest that variations in thyroid function within the laboratory reference range may also affect these parameters.
Patients with hypothyroidism are routinely treated with levothyroxine (L-T4) as replacement therapy. Physicians monitor the L-T4 dose by measuring serum thyroid stimulating hormone (TSH) levels, with the goal of a normal level. However, many patients with normal TSH levels continue to report symptoms, primarily in neurocognitive and metabolic areas. For this reason, patients with hypothyroidism often request higher L-T4 doses, but the clinical consequences of this are unknown.
In the present study, otherwise healthy subjects with treated hypothyroidism and normal TSH levels, ages 20-75 years, will be enrolled in a 7-11 month study. At baseline, the following tests will be performed to measure health status, psychological symptoms, mood, memory, body composition, and energy expenditure: the Short Form Health Survey-36 (SF-36), Profile of Mood States (POMS), Affective Lability Scale (ALS), Letter Cancellation Test (LCT), Trail Making Test, Iowa Gambling Task (IGT), N-Back Test, Subject-Ordered Pointing, Paragraph Recall, Pursuit Rotor, Motor Sequence Learning Test, resting energy expenditure (REE) and thermic effect of food (TEF) by indirect calorimetry, total energy expenditure (TEE) by doubly labelled water, physical activity energy expenditure (PAEE) by accelerometry, diet intake by 24-hour diet recalls, and body composition by dual energy x-ray absorptiometry (DEXA). Following these baseline measurements, subjects will receive either their usual doses of L-T4, or a slightly higher or lower dose. The doses will be chosen to try to achieve either a low-normal TSH level, a high-normal TSH level, or a mildly elevated TSH level. Which target TSH the patient is assigned will be determined randomly, and neither the subject nor the study contacts will know which dose the patient is receiving. Subjects will be seen every 6 weeks during the study for brief visits to make sure they are not having any side effects, and to adjust L-T4 doses if the TSH has not yet reached the target range. At the 24-week visit (end of study), the subjects will undergo the same tests that they had on the baseline visit.
Results from the study will be examined to see if minor changes in TSH or other thyroid hormone levels cause changes in any of the outcomes, and if the degree of TSH change correlates with the degree of outcome changes. These results may help physicians caring for patients with thyroid disease better determine the optimal dose of thyroid hormone for each patient.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| 1 (Low-normal TSH target) | Experimental | Drug: L-thyroxine (L-T4)Treatment arm 1 targets a thyroid stimulating hormone (TSH) of 0.28 -2.49 milliunits/liter (mU/L) (the theoretical optimal range). The intervention is as follows: Levothyroxine (L-T4) doses will be adjusted in this arm to achieve this target TSH range. L-T4 is the intervention. L-T4 is given once per day, in the morning, while fasted. Dose ranges for the study are calculated based on each subject's TSH levels monitored during the study. Duration of the intervention is the duration of the study, after which subjects return to taking their usual L-T4 doses. |
| 2 (High-normal TSH target) | Experimental | Drug: L-thyroxine (L-T4)Treatment arm 2 targeting a TSH of 2.5 - 5.0 mU/L. The intervention is as follows: Levothyroxine (L-T4) doses will be adjusted in this arm to achieve this target TSH range. L-T4 is the intervention. L-T4 is given once per day, in the morning, while fasted. Dose ranges for the study are calculated based on each subject's TSH levels monitored during the study. Duration of the intervention is the duration of the study, after which subjects return to taking their usual L-T4 doses. |
| 3 (Mildly elevated TSH target) | Experimental | Drug: L-thyroxine (L-T4)Treatment arm 3 is targeting a TSH level o f 5.1-12.0 mU/L. The intervention is as follows: Levothyroxine (L-T4) doses will be adjusted in this arm to achieve this target TSH range. L-T4 is the intervention. L-T4 is given once per day, in the morning, while fasted. Dose ranges for the study are calculated based on each subject's TSH levels monitored during the study. Duration of the intervention is the duration of the study, after which subjects return to taking their usual L-T4 doses. |
Who may qualify
- Ages
- 20 to 75 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (10 listed)
- Ages 20-75
- Primary hypothyroidism on stable dose of L-T4 for > 3 months
- Documented elevated TSH off L-T4
- Normal TSH level on usual dose of L-T4
- No acute or chronic medical or psychiatric illnesses that affect thyroid function, mood or cognition
Key exclusion criteria (12 listed)
- Failure to meet any of the above inclusion criteria
- Inability to speak and comprehend English
- A history of coronary artery disease
- Screening hgb <10
- Screening wbc > 10,000
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| L-thyroxine (L-T4)Also: Subjects will remain on their usual brand of L-T4., Subjects on generic L-T4 will be switched to Levoxyl.L-thyroxine (L-T4) is the intervention for each arm/group. In each arm/group, the dose of L-T4 is adjusted to achieve TSH levels in the randomly assigned arm. L-thyroxine at doses appropriate to attain target TSH levels for the different arms for 24 weeks | Drug | 1 (Low-normal TSH target), 2 (High-normal TSH target), 3 (Mildly elevated TSH target) |
Primary outcome
Executive Function
Time frame: 24 weeks
Iowa Gambling Task Net-5. Four decks of cards are shown face down on a computer screen. The subject chooses cards from any deck, resulting in the gain or loss of money. The subject is unaware that 2 decks are advantageous (small gains, smaller losses), while 2 are disadvantageous (large gains, larger losses). The subject's choices are classified as advantageous (X) or disadvantageous (Y), with a net score of X-Y, over 5 trials of 100 cards each. The outcome reported here is the score on the fifth trial, which is generally the best trial due to practice effects. The minimum score is -20 and the maximum score is +20. Higher scores indicate a better outcome.
Resting Energy Expenditure
Time frame: 24 weeks
Measurement of resting energy expenditure (REE) by indirect calorimetry, corrected for lean body mass. Indirect calorimetry is performed at 21.1° C after the participant has fasted for 12h and abstains from significant physical activity for 24h. The indirect calorimeter (VMax Encore 29N Indirect Calorimeter, SensorMedics Viasys Healthcare, Yorba Linda, CA) samples expired air and analyzes it for the volume of oxygen consumed (VO2) and the volume of carbon dioxide produced (VCO2) each minute for 30mins. REE is then calculated using the modified Weir equation. Minimum REE is 23 kcal/kg LBM/day and maximum REE is 39 kcal/kg LBM/day. Within that range, higher levels are considered better for the purposes of this study.
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Aug 2018.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 30165520Samuels MH, Kolobova I, Niederhausen M, Purnell JQ, Schuff KG. Effects of Altering Levothyroxine Dose on Energy Expenditure and Body Composition in Subjects Treated With LT4. J Clin Endocrinol Metab. 2018 Nov 1;103(11):4163-4175. doi: 10.1210/jc.2018-01203.
- Derived from this study: PubMed 29509918Samuels MH, Kolobova I, Niederhausen M, Janowsky JS, Schuff KG. Effects of Altering Levothyroxine (L-T4) Doses on Quality of Life, Mood, and Cognition in L-T4 Treated Subjects. J Clin Endocrinol Metab. 2018 May 1;103(5):1997-2008. doi: 10.1210/jc.2017-02668.
- Derived from this study: PubMed 28460140Samuels MH, Kolobova I, Antosik M, Niederhausen M, Purnell JQ, Schuff KG. Thyroid Function Variation in the Normal Range, Energy Expenditure, and Body Composition in L-T4-Treated Subjects. J Clin Endocrinol Metab. 2017 Jul 1;102(7):2533-2542. doi: 10.1210/jc.2017-00224.
- Derived from this study: PubMed 27338133Samuels MH, Kolobova I, Smeraglio A, Niederhausen M, Janowsky JS, Schuff KG. Effect of Thyroid Function Variations Within the Laboratory Reference Range on Health Status, Mood, and Cognition in Levothyroxine-Treated Subjects. Thyroid. 2016 Sep;26(9):1173-84. doi: 10.1089/thy.2016.0141. Epub 2016 Jul 25.
- Derived from this study: PubMed 26700485Samuels MH, Kolobova I, Smeraglio A, Peters D, Purnell JQ, Schuff KG. Effects of Levothyroxine Replacement or Suppressive Therapy on Energy Expenditure and Body Composition. Thyroid. 2016 Mar;26(3):347-55. doi: 10.1089/thy.2015.0345. Epub 2016 Feb 3.
- Derived from this study: PubMed 24423358Samuels MH, Kolobova I, Smeraglio A, Peters D, Janowsky JS, Schuff KG. The effects of levothyroxine replacement or suppressive therapy on health status, mood, and cognition. J Clin Endocrinol Metab. 2014 Mar;99(3):843-51. doi: 10.1210/jc.2013-3686. Epub 2014 Jan 13.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Mary Samuels, MD principal investigator
Oregon Health and Science University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing L-thyroxine (L-T4) in people with Hypothyroidism, run by Oregon Health and Science University at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 10 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 22 Aug 2018. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 22 Aug 2018). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Executive Function (time frame: 24 weeks). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT00565864, which also lists 6 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Aug 2018.