Differences in thyroid hormone prescribing practices between Japan Thyroid Association-certified thyroid specialists and non-certified members: a nationwide survey in Japan.

Response rates differed substantially between certified specialists and non-certified members in this nationwide survey.

• A total of 2,938 JTA members were surveyed, including 874 certified specialists and 2,064 non-certified members.
• 207 certified specialists (23.7%) responded and completed the questionnaire.
• 129 non-certified members (6.3%) responded and completed the questionnaire.
• The survey instrument used was the 'Treatment of Hypothyroidism in Europe by Specialists: An International Survey' (THESIS) questionnaire.

All certified specialists and non-certified members selected levothyroxine (LT4) as first-line therapy for hypothyroidism.

• LT4 monotherapy was the universal first-line choice across both groups.
• This finding indicates consensus on initial hypothyroidism treatment regardless of certification status.

Certified thyroid specialists used LT3 plus LT4 combination therapy more frequently than non-certified members.

• 28% of certified specialists used combination therapy versus 12% of non-certified members (p < 0.001).
• For LT4-treated patients with persistent hypothyroid-like symptoms specifically, 9% of certified specialists versus 2% of non-certified members selected combination therapy (p = 0.02).
• Certified specialists were more open to combination therapy across hypothyroid patient scenarios.

Certified specialists more frequently considered thyroid hormone treatment for euthyroid individuals than non-certified members.

• 71% of certified specialists considered TH treatment for euthyroid individuals compared to 60% of non-certified members (p = 0.043).
• This difference suggests certified specialists have a broader view of TH therapy indications beyond overt hypothyroidism.

Among non-certified members, higher patient volume was associated with greater inclination to use combination therapy and TH treatment for euthyroid patients.

• Non-certified members who see more than 100 hypothyroid patients per year were more inclined to use combination therapy for hypothyroid patients than those seeing ≤100 patients (p < 0.049).
• Non-certified members seeing >100 hypothyroid patients per year were also more inclined to use TH for euthyroid patients than those seeing ≤100 patients (p = 0.001).
• This suggests clinical experience volume partially influences prescribing patterns independently of specialist certification.

The authors identified a need for updated guidelines and targeted education to rationalize thyroid care based on the observed prescribing differences.

• The differences in prescribing patterns 'underscore the impact of specialization on clinical practice.'
• Non-certified members were characterized as favoring 'guideline-based LT4 monotherapy.'
• Certified specialists were described as 'more open to combination therapy and treating selected euthyroid patients.'
• The authors suggest updated guidelines and targeted education are needed to address these disparities.