Establishing the Adequate Levothyroxine Dose After Total Thyroidectomy: A Systematic Review With Meta-analysis

Area of Science:

• Endocrinology
• Surgical Oncology
• Pharmacology

Background:

• Total thyroidectomy necessitates lifelong levothyroxine (LT4) replacement therapy.
• Early achievement of optimal thyroid hormone levels post-surgery is often difficult.
• No consensus exists on the most effective LT4 dosing strategy for early euthyroidism.

Purpose of the Study:

• To systematically review and meta-analyze the proportion of patients achieving euthyroidism at the first follow-up after total thyroidectomy.
• To compare the effectiveness of different LT4 dosing strategies.

Main Methods:

• Systematic review and meta-analysis of 11 studies (2000-2024) involving 2577 patients.
• Analysis of fixed-dose, weight-based (dose/kg), and algorithm-based LT4 dosing strategies.
• Meta-regression and subgroup analyses to identify heterogeneity sources.

Main Results:

• The pooled euthyroidism rate was 33.9%, with significant heterogeneity (I² = 82.68%).
• No single LT4 dosing strategy consistently outperformed others (dose/kg: 29%; fixed/algorithm: 40%).
• No significant predictors of euthyroidism were identified; no differences based on disease type or study design.

Conclusions:

• Approximately one-third of patients achieve early euthyroidism post-thyroidectomy, irrespective of the LT4 dosing strategy used.
• Current guideline recommendations (e.g., dose/kg) may be insufficient.
• Further research is needed to develop refined individualized dosing protocols and identify influencing factors.