ENDO2017 (Orlando, Florida, April 1 – 7, 2017) proved to be a very exciting congress for those taking care of patients with thyroid disorders. The warm weather was enjoyed by thousands of healthcare professionals from all over the world, with many taking advantage of the pre-conference workshops on both introductory and advanced, hands-on thyroid ultrasound. One undoubted highlight of the meeting was the unveiling of the results of a multi-center trial on the treatment of subclinical hypothyroidism.

During the congress, there were several programs featuring thyroid topics, including:

• Case management forums: low risk thyroid cancer patients, medullary thyroid cancer
• Late-breaking abstracts: prevalence of thyroid incidentalomas in radiology, high prevalence of papillary thyroid carcinoma in type 1 myotonic dystrophy
• Master clinician session: when to be aggressive with aggressive thyroid cancer
• Meet-the-professor sessions: challenging thyroid function tests
• Special scientific session: challenging cases from surgeons and endocrinologists
• Symposia: congenital thyroid disorders; stem cells and genetics

Aside from the interesting oral and poster presentations during the congress, there was also a satellite program from the American Thyroid Association on Hypothyroidism which discussed:

• Understanding the evolution of therapies for hypothyroidism
• Whose normal TSH is better, yours or mine?
• Beyond TSH: T3 levels and deiodinase polymorphisms
• Where do we stand on combination therapy?
• Knowledge gaps: which thyroid measurements are relevant and how does diet impact thyroid function
• Incorporating patient outcomes into management of hypothyroidism
• Hypothyroidism - a patient’s perspective

One of the most anticipated parts of the thyroid sessions was the presentation of the results of the Thyroid Hormone Replacement for Untreated Older Adults with Subclinical Hypothyroidism: A Randomized Placebo-Controlled Trial (TRUST), a multicenter trial from Europe. David Stott (Institute of Cardiovascular and Medical Sciences, University of Glasgow, Scotland) presented the results of this first, large, double-blind, parallel group trial which investigated the clinical benefits of levothyroxine replacement in older persons with subclinical hypothyroidism, defined as an elevated thyrotropin level (4.60-19.99 mIU per liter).

The trial enrolled 369 patients aged ≥65 years with persistent subclinical hypothyroidism who were randomized to receive either levothyroxine or placebo. The dose of levothyroxine was either 50 μg/day or 25 μg/day (if body weight was <50 kg or patient had coronary heart disease). The primary outcomes measured were the Hypothyroid Symptoms Score and Tiredness Score at one year.

Results showed that levothyroxine significantly reduced TSH to a mean of 3.63 mIU per liter compared with 5.48 mIU per liter for placebo. Levothyroxine replacement did not lead to a significant difference in the mean change at one year in the Hypothyroid Symptoms Score and Tiredness Score, nor did it lead to significant excess of serious adverse events of special interest, such as new onset atrial fibrillation or fractures.

The authors had initially planned to investigate the effect of levothyroxine replacement on cardiovascular events and thyroid-specific quality of life. However, the trial was underpowered for cardiovascular events because of delays and difficulties in recruitment so they limited the primary outcomes to only the Hypothyroid Symptoms and Tiredness Scores. In this study, the authors concluded that levothyroxine provided no apparent benefits in older persons with subclinical hypothyroidism. These findings help clinicians in estimating the risks and benefits of treating older patients with subclinical hypothyroidism. The results of the TRUST trial were published in the New England Journal of Medicine¹ simultaneous with the oral presentation.

ENDO2017 truly provided attendees with very valuable insights in improving the care of patients with thyroid disorders.

Reference

1. Stott DJ, et al. N Engl J Med. 2017;376(26):2534-44. http://www.nejm.org/doi/full/10.1056/NEJMoa1603825