title: Lithium as an adjunct to radioactive iodine for the treatment of hyperthyroidism: a systematic review and meta-analysis.
abstract: BACKGROUND
  Radioactive iodine (RAI) is commonly used in the treatment of hyperthyroidism but is not uniformly successful. Lithium increases thyroidal iodine retention without reducing iodide uptake, increasing the radiation dose to the thyroid when administered with RAI. Although these actions suggest that adjuvant lithium may increase the efficacy of RAI, its role as an adjunct to RAI remains contentious.
  
  
  OBJECTIVE
  To evaluate the safety and efficacy of adding lithium to RAI to treat hyperthyroidism.
  
  
  METHODS
  Relevant studies were identified by a search of Medline and the Cochrane Central Register of Controlled Trials. To be included, a study had to be a controlled trial comparing the effect of RAI alone to RAI with lithium in the treatment of hyperthyroidism. Relevant data were extracted and meta-analyses were performed.
  
  
  RESULTS
  Of the 75 identified studies, 6 met the inclusion criteria; 4 of these studies were interventional and 2 were observational trials. Meta-analysis of the observational trials (N = 851), both of which were retrospective cohort studies, showed significant improvement in the primary outcome (i.e., cure rate) with adjunctive lithium (odds ratio [OR], 1.92; 95% confidence interval [CI], 1.24 to 2.96). The combined interventional trials (N = 485) also showed an improvement in cure rate, but the difference did not reach statistical significance (OR, 1.28; 95% CI, 0.85 to 1.91). Adjunctive lithium reduced time to cure and blunted thyroid hormone excursions after RAI. Lithium-related side effects were infrequent and usually mild.
  
  
  CONCLUSIONS
  The observational trials demonstrated significant improvement in the cure rate of hyperthyroidism when lithium is added to RAI. The improvements shown in the interventional trials did not reach statistical significance due to the effect of a single, large negative trial.
authors.affiliation: Division of Endocrinology, John H. Stroger Jr Hospital of Cook County, Chicago, Illinois.
authors.forename: Lynn
authors.initials: L
authors.lastname: Kessler
authors.affiliation: Division of Endocrinology, John H. Stroger Jr Hospital of Cook County, Chicago, Illinois.
authors.forename: Jyothsna
authors.initials: J
authors.lastname: Palla
authors.affiliation: Division of Hospital Medicine, John H. Stroger Jr Hospital of Cook County, Chicago, Illinois.
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Baru
authors.affiliation: Department of Medicine, John H. Stroger Jr Hospital of Cook County, Chicago, Illinois.
authors.forename: Chioma
authors.initials: C
authors.lastname: Onyenwenyi
authors.affiliation: Department of Medicine, John H. Stroger Jr Hospital of Cook County, Chicago, Illinois.
authors.forename: Amrutha M
authors.initials: AM
authors.lastname: George
authors.affiliation: White River Junction VA Medical Center, White River Junction, Vermont.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Lucas
mesh_terms: D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000532:radiotherapy*; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008094:Lithium / Q000627:therapeutic use*; D013963:Thyroid Hormones / Q000097:blood
chemical_list: D007457:Iodine Radioisotopes; D013963:Thyroid Hormones; D008094:Lithium