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Table 2 Co-factors between cohorts of success and failure of first RAI therapy for hyperthyroidism

From: Efficacy of radioactive iodine treatment of graves’ hyperthyroidism using a single calculated 131I dose

Variable Success
(n = 295)
Failure
(n = 21)
P value
Age (y) at time of diagnosis 41.9 45.5 NS (P = 0.32)
Gender (F:M) 226:69 12:9 (P = 0.046)
No prior treatment 176 (59.7%) 3 (14.2%) (P < 0.001)
Prior antithyroid medication 114 (38.6%) 17 (80.9%) (P < 0.001)
Methimazole n = 35 n = 2 (P < 0.001)
Propylthiouracil n = 79 n = 15 (P < 0.001)
Interval from diagnosis to treatment (d) 329.6 289.6 (P = 0.024)
Size of thyroid gland (grams) 49.3 62.1 (P = 0.0017)
24-h RAIU uptake 0.56 0.62 NS (P = 0.235)
Dose of RAI 131I administered (mCi) 18.1 19.9 NS (P = 0.193)
Dosing factor (mCi per gram) 0.21 0.19 NS (P = 0.259)
Weight (lbs) 150.1 136.8 NS (P = 0.050)
Thyrotropin (TSH)
(normal 0.3–5.5 mIU/L)
0.13 0.010 NS (P = 0.948)
Total tri-iodothyronine (TT3)
(normal 95–170 pg/mL)
328 415 NS (P = 0.139)
Free thyroxine (FT4)
(normal 0.73–1.79 ng/dL)
3.2 3.8 (P = 0.026)
Race: caucasian 212 (71.8%) 11 (52.5%) NS (P = 0.195)