Effects of antithyroid drugs on radioiodine treatment: Systematic review and meta-analysis of randomised controlled trials

Objective: To determine the effect of adjunctive antithyroid drugs on the risk of treatment failure, hypothyroidism, and adverse events after radioiodine treatment. Design: Meta-analysis. Data sources: Electronic databases (Cochrane central register of controlled trials, Medline, Embase) searched to August 2006 and contact with experts. Review methods: Three reviewers independently assessed trial eligibility and quality. Pooled relative risks for treatment failure and hypothyroidism after radioiodine treatment with and without adjunctive antithyroid drugs were calculated with a random effects model. Results: We identified 14 relevant randomised controlled trials with a total of 1306 participants. Adjunctive antithyroid medication was associated with an increased risk of treatment failure (relative risk 1.28, 95% confidence interval 1.07 to 1.52; P=0.006) and a reduced risk for hypothyroidism (0.68, 0.53 to 0.87; P=0.006) after radioiodine treatment. We found no difference in summary estimates for the different antithyroid drugs or for whether antithyroid drugs were given before or after radioiodine treatment. Conclusions: Antithyroid drugs potentially increase rates of failure and reduce rates of hypothyroidism if they are given in the week before or after radioiodine treatment, respectively.