Open Access Open Badges Study protocol

The chronic autoimmune thyroiditis quality of life selenium trial (CATALYST): study protocol for a randomized controlled trial

Kristian Hillert Winther1*, Torquil Watt2, Jakob Bue Bjørner34, Per Cramon2, Ulla Feldt-Rasmussen2, Christian Gluud5, Jeppe Gram6, Mogens Groenvold47, Laszlo Hegedüs1, Nils Knudsen8, Åse Krogh Rasmussen2 and Steen Joop Bonnema1

Author Affiliations

1 Department of Endocrinology and Metabolism, Odense University Hospital Kloevervaenget 4-6, DK-5000 Odense C, Odense, Denmark

2 Department of Medical Endocrinology, Rigshospitalet, Copenhagen University, Copenhagen, Denmark

3 National Research Centre for the Working Environment, Copenhagen, Denmark

4 Institute of Public Health Science, Copenhagen University, Copenhagen, Denmark

5 Copenhagen Trial Unit, Centre for Clinical Intervention Research, Rigshospitalet, Copenhagen, Denmark

6 Department of Endocrinology, Hospital of Southwest Denmark, Esbjerg, Denmark

7 Department of Oncology, Bispebjerg Hospital, Copenhagen, Denmark

8 Department of Endocrinology, Bispebjerg Hospital, Copenhagen, Denmark

For all author emails, please log on.

Trials 2014, 15:115  doi:10.1186/1745-6215-15-115

Published: 9 April 2014



Patients with chronic autoimmune thyroiditis have impaired health-related quality of life. The thyroid gland has a high selenium concentration, and specific selenoprotein enzyme families are crucial to immune function, and catalyze thyroid hormone metabolism and redox processes in thyroid cells. Previous randomized controlled trials have found that selenium supplementation decreases thyroid-disease-specific antibody levels. We hypothesize that selenium might be beneficial in the treatment of chronic autoimmune thyroiditis.


The CATALYST trial is an investigator-initiated randomized, blinded, multicentre clinical trial of selenium supplementation versus placebo in patients with chronic autoimmune thyroiditis. Inclusion criteria: age ≥18 years; serum thyroid peroxidase antibody level ≥100 IU/ml within the previous 12 months; treatment with levothyroxine and written informed consent. Exclusion criteria: previous diagnosis of toxic nodular goitre, Graves’ hyperthyroidism, postpartum thyroiditis, Graves’ orbitopathy; previous antithyroid drug treatment, radioiodine therapy or thyroid surgery; immune-modulatory or other medication affecting thyroid function; pregnancy, planned pregnancy or breastfeeding; allergy towards any intervention or placebo component; intake of selenium supplementation >55 μg/day; inability to read or understand Danish or lack of informed consent. The trial will include 2 × 236 participants. The experimental intervention and control groups will receive 200 μg selenium-enriched yeast or matching placebo tablets daily for 12 months. The experimental supplement will be SelenoPrecise®. The primary outcome is thyroid-related quality of life assessed by the Thyroid Patient-Reported Outcome (ThyPRO) questionnaire. Secondary outcomes include serum thyroid peroxidase antibody concentration; serum triiodothyronine/thyroxine ratio; levothyroxine dosage; adverse reactions and serious adverse reactions and events.


In this pragmatic trial, participating patients follow their usual treatment at their usual hospitals. In order to collect high-quality data on the clinical course and quality of life, and to minimize missing data, an elaborate trial management system has been designed. 12 months intervention duration was selected in consideration of the primary outcome, thyroid-related quality of life.

Trial registration ID: NCT02013479.

chronic autoimmune thyroiditis; hypothyroidism; quality of life; selenium supplementation; ThyPRO