Quality of life, clinical outcomes and safety of early prophylactic levothyroxine administration in patients with Graves' hyperthyroidism undergoing radioiodine therapy: a randomized controlled study

Objective: While radioiodine therapy is commonly used for treating Graves' disease, a prolonged and clinical hypothyroidism may result in disabling symptoms leading to deterioration of quality of life (QoL) of patients. Introducing levothyroxine (LT4) treatment in the early post-therapeutic period may be an interesting approach to limit this phenomenon. Methods: A multicenter, prospective, open-label randomized controlled trial enrolled 94 patients with Graves' hyperthyroidism randomly assigned to the experimental group (n=46) (group A: early prophylactic LT4 treatment) or the control group (n=48) (group B: standard follow-up). The primary endpoint was the 6-month QoL. The secondary endpoints were other QoL scores such as Graves' ophthalmopathy (GO) outcomes, thyroid function tests and safety. Results: The primary endpoint at 6 months was achieved: the mental composite score (MCS) of Short Form 36 (SF-36) was significantly higher in group A compared to group B (P=0.009). Four other dimension scores of the SF-36 and four dimension scores of the thyroid-specific patient-reportedoutcome (ThyPRO) significantly differed between the two groups, indicating better QoL in group A. After adjustment for variables, the early LT4 administration strategy was found as an independent factor for only two scores of SF-36: the MCS and the general health (GH) score. There were no differences in GO, final thyroid status and changes in the anti-TSH receptor antibodies (TRAbs) levels between the two groups. No adverse cardiovascular event was reported. Conclusion: Early LT4 administration post-radioactive iodine (RAI) could represent a safe potential benefit for patients with regard to QoL. The optimal strategy taking into account administered RAI activities and LT4 treatment dosage and timing remains to be determined.