Clinical Trial: Comparison of Different Doses of 131I in Severe Graves' Hyperthyroidism

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Comparison of Different Doses of 131I in Severe Graves' Hyperthyroidism: A Clinical Trial With Historical Control

Brief Summary: The purpose of this study is to determine whether higher doses of radioiodine increase treatment efficacy in severe Graves' disease.

Detailed Summary: Graves' disease (GD) is the most frequent cause of hyperthyroidism, affecting mainly women aged 40-60 years. Radioiodine (¹³¹I), introduced in 1941, has become a cornerstone in the treatment of GD hyperthyroidism. Because of its safety, low costs and rapid effect, it is considered a first line therapy in the United States. However, treatment failure occurs in about 15-25% of patients treated with radioiodine. Patients not cured with the first dose of radioiodine usually present severe hyperthyroidism, characterized by large goiter, high 24-hour radioiodine uptake (24h-RAIU) and very high levels of thyroid hormones. We have previously shown that large goiter (≥48ml) is an independent predictor of treatment failure. In these patients, the therapeutic failure was 40.0% while in patients with smaller goiter was only 6.5% (P=0.005; unpublished). It is generally accepted that higher doses of radioiodine improves cure rates. Indeed, a recent meta-analysis found a correlation between radioiodine dose and therapeutic success in GD patients. To our knowledge, there are no published studies evaluating cure rates with different radioiodine doses in severe GD.
Sponsor: Hospital de Clinicas de Porto Alegre

Current Primary Outcome: Cure, defined as euthyroidism or permanent hypothyroidism based on FT4 measurements. [ Time Frame: 12 months ]

Original Primary Outcome: Same as current

Current Secondary Outcome:

  • Euthyroidism [ Time Frame: 12 months ]
  • Permanent hypothyroidism [ Time Frame: 12 months ]


Original Secondary Outcome: Same as current

Information By: Hospital de Clinicas de Porto Alegre

Dates:
Date Received: December 24, 2009
Date Started: February 1997
Date Completion:
Last Updated: September 4, 2012
Last Verified: September 2012