Trial Outcomes & Findings for Early Levothyroxine Post Radioactive Iodine (NCT NCT01950260)

Results Overview

Incidence of overt hypothyroidism at 8 weeks post radioactive iodine treatment (RAI). Overt hypothyroidism was defined as thyroid stimulating hormone (TSH) test result \> 3.0 milliunits per liter (mIU/L) or thyroid hormone free T4 (fT4) \< 0.8 nanograms per deciliter (ng/dL). Free T4 is the portion of total T4 thyroid hormone that is available to your tissues in your bloodstream.

Recruitment status

COMPLETED

Study phase

PHASE2/PHASE3

Target enrollment

61 participants

Primary outcome timeframe

8 weeks

Results posted on

2019-10-29

Participant Flow

Participant milestones

Participant milestones
Measure	Levothyroxine In the intervention arm patients will start levothyroxine therapy at 4 weeks after RAI therapy. The initial dose of levothyroxine will be 25 mcg/day. It will be increased to 50 mcg/day 2 weeks later and then adjusted at 8 weeks post RAI based on a full face-to-face clinical and biochemical evaluation. Levothyroxine: Early initiation of levothyroxine after radioactive iodine (to start at 4 weeks).	Placebo In the control arm patients will receive placebo capsules and be evaluated for levothyroxine therapy during a full face-to-face evaluation at 8 weeks. Placebo: Placebo to start at 4 weeks after RAI
Overall Study STARTED	30	31
Overall Study COMPLETED	30	31
Overall Study NOT COMPLETED	0	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Race and Ethnicity were not collected from any participant.

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Levothyroxine n=30 Participants In the intervention arm patients will start levothyroxine therapy at 4 weeks after RAI therapy. The initial dose of levothyroxine will be 25 mcg/day. It will be increased to 50 mcg/day 2 weeks later and then adjusted at 8 weeks post RAI based on a full face-to-face clinical and biochemical evaluation. Levothyroxine: Early initiation of levothyroxine after radioactive iodine (to start at 4 weeks).	Placebo n=31 Participants In the control arm patients will receive placebo capsules and be evaluated for levothyroxine therapy during a full face-to-face evaluation at 8 weeks. Placebo: Placebo to start at 4 weeks after RAI	Total n=61 Participants Total of all reporting groups
Age, Continuous	47 years STANDARD_DEVIATION 15 • n=30 Participants	48 years STANDARD_DEVIATION 13 • n=31 Participants	47.5 years STANDARD_DEVIATION 14 • n=61 Participants
Sex: Female, Male Female	23 Participants n=30 Participants	26 Participants n=31 Participants	49 Participants n=61 Participants
Sex: Female, Male Male	7 Participants n=30 Participants	5 Participants n=31 Participants	12 Participants n=61 Participants
Race and Ethnicity Not Collected	—	—	0 Participants Race and Ethnicity were not collected from any participant.
Region of Enrollment United States	30 participants n=30 Participants	31 participants n=31 Participants	61 participants n=61 Participants
Weight	68.5 kg STANDARD_DEVIATION 16.6 • n=30 Participants	73.4 kg STANDARD_DEVIATION 17.5 • n=31 Participants	70.9 kg STANDARD_DEVIATION 17 • n=61 Participants
Thyroid size	32.7 grams STANDARD_DEVIATION 10.8 • n=30 Participants	31.4 grams STANDARD_DEVIATION 13.9 • n=31 Participants	32 grams STANDARD_DEVIATION 12.3 • n=61 Participants

PRIMARY outcome

Timeframe: 8 weeks

Incidence of overt hypothyroidism at 8 weeks post radioactive iodine treatment (RAI). Overt hypothyroidism was defined as thyroid stimulating hormone (TSH) test result \> 3.0 milliunits per liter (mIU/L) or thyroid hormone free T4 (fT4) \< 0.8 nanograms per deciliter (ng/dL). Free T4 is the portion of total T4 thyroid hormone that is available to your tissues in your bloodstream.

Outcome measures

Outcome measures
Measure	Levothyroxine n=30 Participants In the intervention arm patients will start levothyroxine therapy at 4 weeks after RAI therapy. The initial dose of levothyroxine will be 25 mcg/day. It will be increased to 50 mcg/day 2 weeks later and then adjusted at 8 weeks post RAI based on a full face-to-face clinical and biochemical evaluation. Levothyroxine: Early initiation of levothyroxine after radioactive iodine (to start at 4 weeks).	Placebo n=31 Participants In the control arm patients will receive placebo capsules and be evaluated for levothyroxine therapy during a full face-to-face evaluation at 8 weeks. Placebo: Placebo to start at 4 weeks after RAI
Number of Participants With Overt Hypothyroidism	11 Participants	17 Participants

SECONDARY outcome

Timeframe: 4 weeks, 8 weeks

The mean change in Quality of life scores was measured by the Hypothyroid-Health Related Quality of Life (HRQL) questionnaire. This questionnaire consists of 27 questions specifying the severity of the discomfort or symptoms of hypothyroidism using a 5 point scale for each question with "not at all"=1 to "all the time"=5. Higher scores are associated with a lower quality of life. The change between weeks 4 and 8 were assessed using a hierarchical linear model. The primary parameter of interest from the model was the treatment by time interaction term. Time was a collection of indicator values representing each assessment point.

Outcome measures

Outcome measures
Measure	Levothyroxine n=30 Participants In the intervention arm patients will start levothyroxine therapy at 4 weeks after RAI therapy. The initial dose of levothyroxine will be 25 mcg/day. It will be increased to 50 mcg/day 2 weeks later and then adjusted at 8 weeks post RAI based on a full face-to-face clinical and biochemical evaluation. Levothyroxine: Early initiation of levothyroxine after radioactive iodine (to start at 4 weeks).	Placebo n=31 Participants In the control arm patients will receive placebo capsules and be evaluated for levothyroxine therapy during a full face-to-face evaluation at 8 weeks. Placebo: Placebo to start at 4 weeks after RAI
Change in Hypothyroid-Health Related Quality of Life	12 units on a scale Standard Deviation 28.4	19.8 units on a scale Standard Deviation 25.0

SECONDARY outcome

Timeframe: 4 weeks, 8 weeks

The mean change in quality of life scores was measured by the Thyroid Specific Questionnaire (TSQ). This questionnaire consists of 12 questions ranked on a four-point scale for each question where 0 is 'better than usual' and 3 is 'much less than usual'. A higher score indicates higher levels of dissatisfaction and a lower quality of life. The change between weeks 4 and 8 were assessed using a hierarchical linear model. The primary parameter of interest from the model was the treatment by time interaction term. Time was a collection of indicator values representing each assessment point.

Outcome measures

Outcome measures
Measure	Levothyroxine n=30 Participants In the intervention arm patients will start levothyroxine therapy at 4 weeks after RAI therapy. The initial dose of levothyroxine will be 25 mcg/day. It will be increased to 50 mcg/day 2 weeks later and then adjusted at 8 weeks post RAI based on a full face-to-face clinical and biochemical evaluation. Levothyroxine: Early initiation of levothyroxine after radioactive iodine (to start at 4 weeks).	Placebo n=31 Participants In the control arm patients will receive placebo capsules and be evaluated for levothyroxine therapy during a full face-to-face evaluation at 8 weeks. Placebo: Placebo to start at 4 weeks after RAI
Change in Thyroid Specific Quality of Life	-2 units on a scale Standard Deviation 12.8	-3.8 units on a scale Standard Deviation 8.7

Adverse Events

Levothyroxine

Serious events: 1 serious events

Other events: 3 other events

Deaths: 0 deaths

Placebo

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Serious adverse events
Measure	Levothyroxine n=30 participants at risk In the intervention arm patients will start levothyroxine therapy at 4 weeks after RAI therapy. The initial dose of levothyroxine will be 25 mcg/day. It will be increased to 50 mcg/day 2 weeks later and then adjusted at 8 weeks post RAI based on a full face-to-face clinical and biochemical evaluation. Levothyroxine: Early initiation of levothyroxine after radioactive iodine (to start at 4 weeks).	Placebo n=31 participants at risk In the control arm patients will receive placebo capsules and be evaluated for levothyroxine therapy during a full face-to-face evaluation at 8 weeks. Placebo: Placebo to start at 4 weeks after RAI
Cardiac disorders Atrial fibrillation	3.3% 1/30 • Number of events 1 • Adverse events were collected for each subject from enrollment until study completion, approximately 6 months.	0.00% 0/31 • Adverse events were collected for each subject from enrollment until study completion, approximately 6 months.

Other adverse events

Other adverse events
Measure	Levothyroxine n=30 participants at risk In the intervention arm patients will start levothyroxine therapy at 4 weeks after RAI therapy. The initial dose of levothyroxine will be 25 mcg/day. It will be increased to 50 mcg/day 2 weeks later and then adjusted at 8 weeks post RAI based on a full face-to-face clinical and biochemical evaluation. Levothyroxine: Early initiation of levothyroxine after radioactive iodine (to start at 4 weeks).	Placebo n=31 participants at risk In the control arm patients will receive placebo capsules and be evaluated for levothyroxine therapy during a full face-to-face evaluation at 8 weeks. Placebo: Placebo to start at 4 weeks after RAI
Cardiac disorders Palpitations	10.0% 3/30 • Number of events 3 • Adverse events were collected for each subject from enrollment until study completion, approximately 6 months.	0.00% 0/31 • Adverse events were collected for each subject from enrollment until study completion, approximately 6 months.

Additional Information

Dr. Marius N. Stan

Mayo Clinic

Phone: 507-284-2463

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place