Abstract:

Objective  To analyze the effect of antithyroid drugs (ATD) on the efficacy of ¹³¹I for treating Graves' disease (GD). Methods  Data of 460 cases of GD treated by ¹³¹I was retrospectively analyzed. Patients were cured and followed up for more than one year. Among them, 130 were males (28.3%) and 330 were females (71.7%). Their age was 11-84 years and average age was (41.8±13.4) years. Patients were divided into two groups, i.e. non ATD group (control group) and ATD group (analysis group), according to whether administration of ATD before treatment. The analysis group was divided into the drug withdrawal above 2 weeks subgroup and drug withdrawal under 2 weeks subgroup according to the drug withdrawal time before treatment. The differences of therapeutic effect of groups after first treatment were compared and the proper withdrawal time of ATD before treatment was analyzed. Results  ①The differences of age, 24 h ¹³¹I uptake rate, and ¹³¹I dose and thyroid mass ratio between the control group and analysis group were not statistically significant (t=-1.77-1.76, P>0.05). ②The first time cure rates of the control group and two analysis subgroups were 94.9% (74/78), 65.0% (89/137), and 83.3% (204/245) respectively, with χ²=5.71-22.64 and P<0.05 or 0.01. The later hypothyroidism rates of three groups were 66.7% (52/78), 38.0% (52/137), and 54.7% (134/245) respectively, with χ²=3.98-15.28 and P<0.05 or 0.01. ③The withdrawal time of ATD was positively correlated with the cure rate (r=0.96, P<0.01). The cure rate of analysis group was close to that of the control group for withdrawal time of ATD was more than 8 weeks. Conclusion  Administration of ATD and inadequate withdrawal time of ATD before ¹³¹I treatment of patients with GD can affect the therapeutic effect of ¹³¹I and decrease the first time cure rate. The effect of administration of ATD will be eliminated for withdrawal time of ATD is more than 8 weeks.

Key words: antithyroid drugs, Graves' disease, ¹³¹I, hypothyroidism