SAT-342 - Comparison between Liquid and Tablet Formulations of Levothyroxine in the Treatment of Congenital Hypothyroidism: A Systematic Review and Meta-Analysis

Introduction: Congenital hypothyroidism (CH) is a neonatal endocrine disorder characterized by insufficient production of thyroid hormones (T3, T4), which are essential for normal growth and neurodevelopment. Levothyroxine is synthetic thyroxine used for the treatment of CH. It is available in liquid and tablet formulations. Evaluating the effectiveness of these formulations is therefore essential for better management in infants with CH.


Objective: To compare the effectiveness of liquid and tablet formulations of levothyroxine in the treatment of congenital hypothyroidism.


Method: A systematic literature search was conducted across electronic databases from inception till January 2026. Four Cohort studies, including two groups of neonates treated with liquid (Experimental Group) and tablet formulation (Control Group) of levothyroxine, were retrieved. Outcomes included thyroid-stimulating hormone (TSH) and free thyroxine (fT4) levels at the time of diagnosis (7-15 days) and follow-up at 1,3,6 and 12 months, total Developmental Quotient (DQ) and its subscales (locomotor, personal-social, hearing and language, eye and hand coordination, performance) at 12 months. Mean Differences (MDs) or Standardized Mean Differences (SMDs) with 95% Confidence Intervals (CI) were calculated for continuous outcomes.


Results: This systematic review and meta-analysis included a total of 437 patients. TSH regulation was comparable between the two groups at one month (SMD = -0.03, 95% CI = [-0.78; 071], p = 0.9323) and at 12-month follow-up (SMD = -0.06, 95% CI = [-0.29;0.16], p = 0.5825). Similarly, fT4 levels showed no statistically significant difference between groups at 1 month (SMD = 0.21, 95% CI: −0.01 to 0.43; p = 0.0594), and at 12 months (SMD = −0.07, 95% CI: −0.04 to 0.30; p = 0.7092). Neurodevelopmental outcomes were also comparable between the two groups (SMD = -0.23, 95% CI = [-0.76; 0.29], p = 0.3887).


Conclusions: Both liquid and tablet formulations of levothyroxine are effective in the treatment of congenital hypothyroidism. No statistically significant differences were observed between the two formulations in terms of TSH regulation, fT4 levels, or neurodevelopmental outcomes at short-term or 12-month follow-up.

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