Iodine restrictive diet adversely affects Graves’ disease management

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Takeaway

  • Recurrence after anti-thyroid drug therapy (ATDT) withdrawal is lower for iodine supplemented vs restrictive diet post-ATDT for Graves’ disease (GD).

Why this matters

  • Relation between iodine intake and ATDT effectiveness had been suggested previously, and few studies have tried iodine restrictive diet for GD management.
  • Relatively less is known about benefits of iodine optimal diet for reduced GD recurrence post-ATDT.

Study design

  • Study evaluated 405 patients with newly diagnosed GD who remained on strict dietary iodine restriction ATDT.
  • 1 month later, patients were randomly allocated to either iodine supplemented (n=203) or restricted (n=202) groups.
  • Funding: Natural Science Foundation of China.

Key results

  • GD recurrence was significantly lower in the iodine supplemented vs restricted group (HR, 1.381; P=.04) in 12 months of follow-up after ATDT withdrawal.
  • Thyrotropin receptor antibody levels were significantly lower in the iodine supplemented vs restricted group from 9 to 24 months (P<.001).
  • Urine iodine concentration was significantly higher for the supplemented vs restrictive (161 vs 38 μg/L; P<.001) group, but within recommended standards for both.

Limitations

  • Recurrence after 12 months of ATDT withdrawal not covered.