Impact of lithium on efficacy of radioactive iodine therapy for Graves' disease: a cohort study on cure rate, time to cure, and frequency of increased serum thyroxine after antithyroid drug withdrawal.
BACKGROUND
Radioactive iodine (RAI) is a common therapy for hyperthyroidism due to Graves' disease. A small but significant proportion of patients have recurrence of hyperthyroidism after RAI therapy. Lithium might increase RAI effectiveness by increasing RAI retention in the thyroid. However, whether lithium favorably affects the long-term outcome of RAI therapy is still a matter of argument.


OBJECTIVE
The objective of the study was to compare the efficacy of RAI given with or without concomitant lithium treatment.


METHODS
This was a retrospective cohort study.


METHODS
The study was conducted at a tertiary university center.


METHODS
Six hundred fifty-one patients with newly diagnosed Graves' disease participated in the study.


METHODS
Two hundred ninety-eight patients were treated with RAI plus lithium (900 mg/d for 12 d) and 353 with RAI alone.


METHODS
Proportion of cured patients and time to achieve cure of hyperthyroidism during 1 yr of follow-up was measured.


RESULTS
PATIENTS treated with RAI plus lithium had a higher cure rate (91.0%) than those treated with RAI alone (85.0%, P = 0.030). In addition, patients treated with RAI plus lithium were cured more rapidly (median 60 d) than those treated with RAI alone (median 90 d, P = 0.000). Treatment with lithium prevented the serum free T(4) increase after methimazole withdrawal and RAI therapy. Side effects after RAI therapy occurred in a subset of patients and were mild, transient, and without differences in the two groups.


CONCLUSIONS
RAI combined with lithium is safe and more effective than RAI alone in the cure of hyperthyroidism due to Graves' disease.
Bogazzi
Fausto
F
Department of Endocrinology and Metabolism, and Epidemiology and Biostatistics Unit (G.R.), Institute of Clinical Physiology, National Research Council, 56124 Pisa, Italy. fbogazzi@hotmail.com
Giovannetti
Clara
C
Fessehatsion
Rezene
R
Tanda
Maria Laura
ML
Campomori
Alberto
A
Compri
Emanuele
E
Rossi
Giuseppe
G
Ceccarelli
Claudia
C
Vitti
Paolo
P
Pinchera
Aldo
A
Bartalena
Luigi
L
Martino
Enio
E
D000293:Adolescent; D000328:Adult; D000368:Aged; D013956:Antithyroid Agents / Q000627:therapeutic use; D015331:Cohort Studies; D005260:Female; D006111:Graves Disease / Q000097:blood / Q000188:drug therapy* / Q000453:epidemiology / Q000532:radiotherapy*; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000188:drug therapy / Q000453:epidemiology* / Q000532:radiotherapy; D015994:Incidence; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008094:Lithium / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012074:Remission Induction; D012189:Retrospective Studies; D013974:Thyroxine / Q000097:blood*; D013997:Time Factors; D016896:Treatment Outcome; D028761:Withholding Treatment; D055815:Young Adult
D013956:Antithyroid Agents; D007457:Iodine Radioisotopes; D008094:Lithium; D013974:Thyroxine