There is no comparative cost-utility study between 131I
therapy and
antithyroid drugs (ATD)
therapy for
Graves' disease, though 131I
therapy has higher remission rate and less side effects. The objective of the study was to analyze the cost-utility of ATD
therapy versus 131I
therapy by calculating life-long medical costs and utility, based on the responses of
Graves' disease patients to questionnaires. To determine the expected cost and expected utility, a decision tree analysis was designed on the basis of the 2 competing strategies of ATD
therapy versus 131I
therapy. A simulation of 1000 female patients weighing > or =50 kg who assumed to experience the onset of
Graves' disease at the age of 30, to first complain of thyrotoxic symptoms and moderate
goiter 2-3 mo. previously, and to undergo a 40-years-long cohort study, was created for each strategy using a decision tree and baselines of other relevant variables. The variables and costs were based on the literature and hospital bills. The maximum and minimum values of utility were defined as 1.0 and 0.0, respectively. Future costs and utilities were discounted 5%. The medical costs and utilities were 85,739-88,650 yen/patient/40 years and 16.47-16.56/patient/40 years, respectively, for the ATD
therapy strategy, and 81,842 yen/patient/40 years and 17.41/patient/40 years, respectively, for the 131I
therapy strategy. These results quantitatively demonstrated that the 131I
therapy strategy was superior to the ATD
therapy strategy in terms of both cost and utility. 131I
therapy should be used more widely in Japan because of its greater utility and lower cost.