Markedly Elevated Preoperative Thyroid-Stimulating Hormone Levels and Greater Operative Difficulty in Graves'...

Preoperative management of Graves' disease (GD) typically includes antithyroid drugs, β-blockers, and short-term iodine. However, intensified therapy may result in excessive elevation of thyroid-stimulating hormone (TSH). Whether a TSH threshold (≥10.0 μIU/mL) can determine greater operative difficulty in such patients is unclear. Therefore, we assessed this association in patients with GD who underwent total thyroidectomy.

This retrospective cohort study included consecutive patients with GD who underwent total thyroidectomy at a single center between 2009 and 2022 (n = 1516). The primary analysis comprised a complete case-cohort design (n = 1407; TSH ≥ 10.0 group, n = 48; TSH < 10.0 group, n = 1359). Primary outcomes included intraoperative blood loss, enlargement ratio (ER; estimated preoperative thyroid weight/preadmission thyroid weight), and operative time. Secondary outcomes were perioperative complications and resected thyroid weight. Multivariable linear or logistic regression included prespecified covariates. Rare events were modeled using Firth's penalized logistic regression. For temporal context, we compared preadmission and preoperative TSH levels. Preoperative TSH was modeled as four clinically defined categories based on the institutional reference range to address heterogeneity within the TSH < 10.0 μIU/mL category.

Of 1407 patients, 48 (3.4%) had preoperative TSH ≥ 10.0 μIU/mL. Unadjusted analyses indicated that the TSH ≥ 10.0 group had greater blood loss (median, 52 mL vs. 34 mL; p < 0.001), higher ERs (1.137 vs. 1.029), longer operative times (129 minutes vs. 112 minutes), and heavier resected thyroids (131.8 g vs. 97.0 g). Adjusted models indicated that TSH ≥ 10.0 was independently associated with greater blood loss (β = 53.03 mL; p < 0.001) and higher ERs (β = 0.12; p = 0.002). Dichotomized analyses indicated that TSH ≥ 10.0 increased the odds of ER ≥ 1.1 (adjusted odds ratio [aOR] 2.60; p = 0.004) and operative times ≥ 120 minutes (aOR: 2.29; p = 0.018). Preadmission TSH ≥ 10.0 μIU/mL was more common in the TSH ≥ 10.0 group (20.8% vs. 3.2%), indicating earlier elevation.

Preoperative TSH ≥ 10.0 μIU/mL was independently associated with greater blood loss and higher ERs in patients with GD who underwent total thyroidectomy. Avoiding iatrogenic hypothyroidism and marked TSH elevation during preoperative preparation may improve operative conditions.