Clinical Outcome And Related Risk Factors In Patients Receiving¹³¹I For Graves Disease

ObjectiveGraves disease is one of the most common endocrine diseases,131Ⅰ has been used for treatment of Graves disease for over70years all over the world due to its low price, mild side effects, and simplicity. However, efficacy of131Ⅰ treatment is affected by many factors, such as age, state of disease, thyroid weight, iodine uptake rate, dose of treatment, and individual susceptibility. Till now, there’s still no common consensus about clinical outcome and related risk factors in patients receiving131Ⅰ for Graves disease. Therefore, multivariate analysis is required for the development of individualized treatment program.1007patients of Graves disease that received131Ⅰ treatment in our hospital since2005to2010were retrospectively studied to identify the related risk factors of clinical outcome.MethodClinical history of1007cases of Graves disease admitted in department of endocrinology of our hospital during2005-2010were recorded in detail, including gender, age, duration of Graves disease, family history, medication history, degree of goiter, smoking history, degree of lymphadenopathy and surgical history. Laboratory tests:thyroid function (TSH, total T3, total T4, free T3, free T4, TPOAb, TgAb, iodine uptake; thyroid weight, oral dose of radioactive iodine). If antithyroid drugs were administered, these were withdrawn a week before131Ⅰ therapy. If the symptoms of Graves disease was severe, P-receptor blockers was taken to control the symptoms. All patients included in this study received calculated amount of radioactive iodine orally in a single dose, followed by clinical observation, biochemical and serological examination. A second dose of131I may be applied if the Graves disease is not cured in six months. All patients were followed up by telephone in2011, and status of thyroid function was determined in reference with previous diagnosis.ResultsAfter the131Ⅰ therapy, seven hundred and sixty six patients completed the last follow-up.102of the cases (13.4%) had their thyroid function returned to normal,536(69.9%) showed hypothyroidism, and128(16.7%) remained hyperthyroidism. Statistical analysis showed that incidence of hypothyroidism was78.2%, the efficiency of clinical treatment was90.1%for patients with thyroid weighing less than30g; incidence of hypothyroidism was74.8%, the efficiency of clinical treatment was88.1%for thyroid weighting30-60g; and incidence of hypothyroidism was58.1%, the efficiency of clinical treatment was72.3%for thyroid weighing more than60g. The differences were statistically significant (P=0.000). incidence of hypothyroidism was89.1%, the efficiency of clinical treatment was97.8%if course of disease was less than3months; incidence of hypothyroidism was75.4%, the efficiency of clinical treatment was90.8%if3-12months; incidence of hypothyroidism was63%, and the efficiency of clinical treatment was77%if over12months. The differences were statistically significant (P=0.000). Multivariate logistic regression analysis showed that course of disease less than1year, thyroid weighed less than60g and secondary isotope therapy was more likely to lead to hypothyroidism. Higher dose of isotope therapy was needed to achieve desired effect if thyroid weighed more than60g and course of disease more than1year.ConclusionBetter efficacy can be achieved if course of disease is less than1year and thyroid weighs less than60g, but hypothyroidism is also more likely; while, higher dose of131Ⅰ is needed if course of disease is more than1year, the thyroid weighs more than60g.