Table 5.

Suggestions for future research made in the 2012 ETA guidelines on the use of L-T4 + L-T3 in the treatment of hypothyroidism [1]

1. Prospective studies in hypothyroid patients starting L-T4 therapy, comparing baseline characteristics between those who will and those who will not be satisfied with the outcome of L-T4 monotherapy.

2. Trials investigating the L-T4/L-T3 dose ratio that best approximates the serum FT4/FT3 concentration ratio in healthy subjects.

3. Randomized clinical trials comparing L-T4 + L-T3 combination therapy and L-T4 monotherapy in hypothyroid patients who have persistent symptoms and/or are carriers of polymorphisms in thyroid hormone transporters and deiodinases.

4. Studies with a slow-release preparation of L-T3.

5. Prospective studies assessing the long-term efficacy and safety of L-T4 + L-T3 combination therapy.

None of these suggestions have been realized seven years later in June 2019