Early Levothyroxine Post Radioactive Iodine

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.

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.

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.