Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Treatment success
Systematic review	1306 people 14 RCTs in this analysis	Proportion of people with treatment failure with antithyroid drug plus radioiodine with radioiodine alone	RR 1.28 95% CI 1.07 to 1.52 P = 0.006 Intention-to-treat analysis	Small effect size	radioiodine alone
Systematic review	1306 people 14 RCTs in this analysis	Proportion of people with treatment failure with antithyroid drug plus radioiodine with radioiodine alone Absolute results not reported	RR 1.34 95% CI 0.96 to 1.88 P = 0.09 Per-protocol analysis		Not significant
Systematic review	565 people 14 RCTs in this analysis Subgroup analysis	Proportion of people with treatment failure 77/271 (28%) with adjuvant antithyroid treatment in the week before radioiodine treatment 55/294 (19%) with radioiodine alone	RR 1.48 95% CI 1.09 to 2.00 P = 0.01	Small effect size	radioiodine alone
Systematic review	565 people 14 RCTs in this analysis Subgroup analysis	Proportion of people with treatment failure 191/442 (43%) with adjuvant antithyroid treatment in the week after radioiodine treatment 116/435 (26%) with radioiodine alone	RR 1.32 95% CI 1.04 to 1.68 P = 0.03	Small effect size	radioiodine alone