Thyroid hormone therapy initiation after hemithyroidectomy: treatment burden, timing, and predictors in a population-based cohort.
To determine the two-year burden, timing, and predictors of thyroid hormone therapy initiation after hemithyroidectomy in previously euthyroid adults.
Retrospective population-based cohort study using de-identified electronic health record data from Clalit Health Services (2003-2020), extracted through the MDClone research platform. Adults undergoing hemithyroidectomy with preoperative TSH < 5.0 mIU/L, no preoperative thyroid hormone therapy, and at least two years of follow-up were included. The primary endpoint was first levothyroxine dispensing or overt biochemical hypothyroidism within 24 months.
Among 8,467 eligible patients, 3,362 (39.7%) reached the endpoint within 24 months: 2,179 (25.7%) by 4 months and 3,100 (36.6%) by 12 months. Extended follow-up identified 558 additional initiations (cumulative 46.3%). Treatment initiation was markedly higher among patients with thyroid cancer (72.7%) than those without (33.4%). The strongest multivariable predictors were preoperative TSH (OR 1.55 per 1 mIU/L; 95% CI, 1.47-1.64) and thyroid cancer (OR 4.99; 95% CI, 4.29-5.81).
Thyroid hormone therapy initiation is common after hemithyroidectomy, affecting nearly 40% of previously euthyroid adults within two years. Preoperative TSH and thyroid cancer identify high-burden subgroups and should inform preoperative counseling when hemithyroidectomy is chosen to preserve endogenous thyroid function.
Retrospective population-based cohort study using de-identified electronic health record data from Clalit Health Services (2003-2020), extracted through the MDClone research platform. Adults undergoing hemithyroidectomy with preoperative TSH < 5.0 mIU/L, no preoperative thyroid hormone therapy, and at least two years of follow-up were included. The primary endpoint was first levothyroxine dispensing or overt biochemical hypothyroidism within 24 months.
Among 8,467 eligible patients, 3,362 (39.7%) reached the endpoint within 24 months: 2,179 (25.7%) by 4 months and 3,100 (36.6%) by 12 months. Extended follow-up identified 558 additional initiations (cumulative 46.3%). Treatment initiation was markedly higher among patients with thyroid cancer (72.7%) than those without (33.4%). The strongest multivariable predictors were preoperative TSH (OR 1.55 per 1 mIU/L; 95% CI, 1.47-1.64) and thyroid cancer (OR 4.99; 95% CI, 4.29-5.81).
Thyroid hormone therapy initiation is common after hemithyroidectomy, affecting nearly 40% of previously euthyroid adults within two years. Preoperative TSH and thyroid cancer identify high-burden subgroups and should inform preoperative counseling when hemithyroidectomy is chosen to preserve endogenous thyroid function.
Authors
Wechsler Wechsler, Marom Marom, Oberman Oberman, Fellner Fellner, Reichenberg Reichenberg, Pitaro Pitaro, Kalmovich Kalmovich
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