Determining the best dose of lithium carbonate as adjuvant therapy to radioactive iodine for the treatment of hyperthyroidism: a systematic review and meta-analysis.

BACKGROUND

Hyperthyroidism poses challenges, and common treatments like Radioactive Iodine (RAI) have limitations, prompting exploration of adjunctive approaches. This meta-analysis evaluates the combined impact of RAI and Lithium carbonate (LiCO3) on cure rates and thyroid hormone levels.

METHODS

We systematically searched Cochrane Library, PubMed, Scopus, and Web of Science for studies comparing LiCO3 combined with RAI to RAI alone. Pooled results analyzed cure rates and Free T3/T4 changes. A subgroup analysis was conducted based on LiCO3 dosage and treatment duration, while meta-regression was performed to assess covariates such as the patient's age, RAI dose, and lithium dose. The risk of bias was evaluated using ROB2, ROBINS-1, and NOS, while the statistical analyses were conducted using Revman software 5.4.1.

RESULTS

Analysis of 14 studies involving 2047 patients revealed a significantly increased cure rate with RAI and LiCO3 compared to RAI alone (RR 1.12, 95% CI [1.03,1.23], p = 0.01). Subgroup analysis revealed higher cure rates with short-duration intensified doses of LiCO3, while short-duration diluted doses reduced cure rates. No significant differences were noted in euthyroid and hypothyroid states. Changes in free T3 showed no significant difference between the arms at 7 days and the most common time point. A significant decrease in free T4 favored RAI with LiCO3 at 7 days (MD -4.90, 95% CI [-7.91, -1.89], p = 0.001), and the most common time point (MD -3.83, 95% CI [-7.45, -0.20], p = 0.04). Meta-regression analysis indicated better cure rates in older patients (p < 0.001) and lower total lithium doses (p < 0.001).

CONCLUSION

Treatment with RAI combined with LiCO3 significantly enhanced cure rates, particularly when using short-duration intensified doses of LiCO3. Additionally, LiCO3 effectively reduced T4 levels without altering T3 levels. Future research is needed to validate our findings.

CLINICAL TRIAL NUMBER: Not applicable.