Date of Award


Degree Type

Selective Evidence-Based Medicine Review

Degree Name

Master of Science in Health Sciences - Physician Assistant

Department Chair

John Cavenagh, PhD, PA-C


OBJECTIVE: The objective of this selective EBM review is to determine whether or not high dose radioactive iodine-131 is more effective than low dose iodine-131 in the therapy of patients with hyperthyroidism.

STUDY DESIGN: The review included three primary English language studies that were peer reviewed articles published in 2003, 2010 and 2011.

DATA SOURCES: This paper evaluates three randomized control trials (one prospective randomized and two comparative randomized) looking at the effectiveness of high dose and low dose radioactive iodine-131 for the treatment of hyperthyroidism.

OUTCOMES MEASURED: Each study examined patients being treated with high or low dose radioactive iodine-131. The outcomes measured include 1) incidence of failed treatment that required further therapy 2) patients that maintained a euthyroid state 3) patients needing therapy for hypothyroidism caused by the radioactive therapy. The measurements were evaluated with laboratory values as well as a 5- point scoring system and clinical symptoms of hyperthyroidism and hypothyroidism. Statistical evaluation is based on p-values and NNT.

RESULTS: Three randomized controlled trials were included in this review. Results from Leslie et al. 2003, found that low dose regimen is as effective as high dose regimen. The conclusion and statistical analysis of Pusuwan et al. 2011, found that high dose regimen would be more effective than low dose regimen. Lastly, the Thientunyakit et al. 2010, study found that neither dose regimen was shown to be more effective in the treatment of hyperthyroidism.

CONCLUSION: All three of the randomized trials in this EBM review contradicted findings in the other. That being said, at this time there is no conclusive evidence to support whether high or low dose radioactive iodine regimen is more effective in the treatment of hyperthyroidism. There has to be continued research and development in this field of study to better determine a dose regimen that is effective in managing patients with this disease.