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Table 2 Outcome measures, their priorities, times of measurement, mathematical types and analytical categories (defining the statistical analysis to which they will be subjected)

From: Selenium supplementation for patients with Graves’ hyperthyroidism (the GRASS trial): study protocol for a randomized controlled trial

Outcome Times of measurements Type of quantity Regression analysis to be applied
Primary outcome    
ATD treatment failure End of trial Binary Logistic regression
Secondary outcomes    
1. ATD treatment within last 12 months End of trial Binary Logistic regression
2. Thyroid hyperfunction after ATD treatment withdrawal End of trial Binary Logistic regression
3. Ablative therapy End of trial Binary Logistic regression
4. Global QoL ThyPRO score a) Time sequence of five measurements Numerical a) Mixed-model with repeated measures (MMRM)
b)12 months following ATD treatment withdrawal b) General linear univariate model. As sensitivity analysis: Mann-Whitney test
5. Level of TRAb After 18 months and at the end of intervention period Numerical General linear univariate model. As sensitivity analysis: Mann-Whitney test
6. ThyPRO - hyperthyroid symptoms a) Time sequence of five measurements Numerical a) Mixed-model with repeated measures (MMRM)
b) 12 months following ATD treatment withdrawal b) General linear univariate model. As sensitivity analysis: Mann-Whitney test
7. ThyPRO - eye symptoms a) Time sequence of five measurements Numerical a) Mixed-model with repeated measures (MMRM)
b) 12 months following ATD treatment withdrawal b) General linear univariate model. As sensitivity analysis: Mann-Whitney test
8. Adverse reactions End of trial Rate = count/period of intervention/day Generalised linear model, Poisson distribution, link = log. As sensitivity analysis: Mann-Whitney test
9. Serious adverse reactions End of trial Rate = count/period of intervention/day Generalised linear model, Poisson distribution, link = log. As sensitivity analysis: Mann-Whitney test
Exploratory outcomes    
1. Time to ATD withdrawal § End of trial Numerical (time until ATD withdrawal (or censoring)) Cox proportional hazard rate model.As sensitivity analysis: Kaplan-Meier estimates of survival function
2. Incidence of Graves’ orbitopathy - CAS score End of trial Binary (CAS >1) Logistic regression
3. ThyPRO - Hypothyroid symptoms a) Time sequence of five measurements Numerical a) Mixed-model with repeated measures (MMRM)
  b) 12 months following ATD treatment withdrawal   b) General linear univariate model. As sensitivity analysis: MannWhitney test
  1. This analysis (2) includes four measurements relative to the reference time (6 weeks, 12 weeks, 6 months and 12 months). This analysis (3) includes one measurement (12 months following ATD treatment withdrawal or failure to withdraw (alternative treatment instituted or deadline expired)) relative to a different reference time. §End of ATD treatment or censoring at 18 months after randomisation or ablative surgery, provided the latter takes place during ATD treatment and prior to time of censoring. ATD, anti-thyroid drugs; QoL, quality of life; ThyPRO, thyroid patient-reported outcome; TRAb, TSH-receptor antibodies; CAS, clinical activity score.