Study Assesses Treatment Dose, Timing of Levothyroxine in Congenital Hypothyroidism

A new systematic review of children with congenital hypothyroidism has demonstrated that early detection and fast treatment with levothyroxine resulted in favorable outcomes. However, researchers were unable to determine an optimal initiation dose of the therapy.

For the study, researchers from Tehran, Iran, analyzed published data on initiation treatment dose and onset time of treatment in congenital hypothyroidism, with the aim of determining the optimal treatment strategy. The search involved multiple electronic databases and websites of relevant organizations, along with reference lists of included studies and issues of major thyroid and pediatrics journals published during the last 35 years.

The final analysis included 22 studies that evaluated levothyroxine (dose, treatment timing, or both) used for the management of children with congenital hypothyroidism. Overall, 17 studies examined outcomes of different treatment doses and 12 studies assessed outcomes of various treatment timings.

Results indicated that initial levothyroxine doses for treating congenital hypothyroidism ranged from 3.21 to 23.6 μg/kg/d. Most studies indicated a high-dose strategy was beneficial for newborns with congenital hypothyroidism; however, researchers were unable to discover strong evidence indicating the precise optimal dosage of initial treatment with levothyroxine in this patient population.

In addition, the analysis revealed that early detection and fast treatment in the shortest time possible is vitally important for congenital hypothyroidism treatment.

“Almost all the studies…have consensus on early treatment, specifically in the first month of infants’ lives,” the researchers wrote. “In this review however we found only one study reporting no correlations between initiation time of treatment and IQ or motor outcomes.”

The researchers added that, for now, the optimal dose of levothyroxine for treatment initiation will remain a controversial topic, “demonstrating the need for further studies, despite the fact that use of high doses can lead to rapid normalization of biochemical indices, although this may cause complications.”

Study limitations included a lack of studies, particularly those with high-level evidence, and the difference in methodologies used in the studies, which precluded a statistical meta-analysis.

Reference

1. Rahmani K, Yarahmadi S, Etemad K, et al. Congenital hypothyroidism: optimal initial dosage and time of initiation of treatment: a systematic review. Int J Endocrinol Metab. 2016;14:e36080. doi: 10.5812/ijem.36080