T4 is standard treatment for hypothyroidism. A recent study reported that combined T4/liothyronine (T3) treatment improved well-being and cognitive function compared with T4 alone. We conducted a double-blind, randomized, controlled trial with a crossover design in 110 patients (101 completers) with primary hypothyroidism in which liothyronine 10 μg was substituted for 50 μg of the patients’ usual T4 dose. No significant (P <0.05) difference between T4 and combined T4/T3 treatment was demonstrated on cognitive function, quality of life scores, Thyroid Symptom Questionnaire scores, subjective satisfaction with treatment, or eight of 10 visual analog scales assessing symptoms. For the General Health Questionnaire-28 and visual analog scales assessing anxiety and nausea, scores were significantly (P <0.05) worse for combined treatment than for T4 alone. Serum TSH was lower during T4 treatment than during combined T4/T3 treatment (mean ± sem, 1.5 ± 0.2 vs. 3.1 ± 0.2 mU/liter; P <0.001), a potentially confounding factor; however, subgroup analysis of subjects with comparable serum TSH concentrations during each treatment showed no benefit from combined treatment compared with T4 alone. We conclude that in the doses used in this study, combined T4/T3 treatment does not improve well-being, cognitive function, or quality of life compared with T4 alone.
|Journal||The Journal of Clinical Endocrinology & Metabolism|
|Publication status||Published - 2003|