CONTEXT: For patients on T(4) replacement, the dose is guided by serum TSH concentrations, but some patients request higher doses due to adverse symptoms. OBJECTIVE: The aim of the study was to determine the safety of patients having a low but not suppressed serum TSH when receiving long-term T(4) replacement. DESIGN: We conducted an observational cohort study, using data linkage from regional datasets between 1993 and 2001. SETTING: A population-based study of all patients in Tayside, Scotland, was performed. PATIENTS: All patients taking T(4) replacement therapy (n = 17,684) were included. MAIN OUTCOME MEASURES: Fatal and nonfatal endpoints were considered for cardiovascular disease, dysrhythmias, and fractures. Patients were categorized as having a suppressed TSH (<or=0.03 mU/liter), low TSH (0.04-0.4 mU/liter), normal TSH (0.4-4.0 mU/liter), or raised TSH (>4.0 mU/liter). RESULTS: Cardiovascular disease, dysrhythmias, and fractures were increased in patients with a high TSH: adjusted hazards ratio, 1.95 (1.73-2.21), 1.80 (1.33-2.44), and 1.83 (1.41-2.37), respectively; and patients with a suppressed TSH: 1.37 (1.17-1.60), 1.6 (1.10-2.33), and 2.02 (1.55-2.62), respectively, when compared to patients with a TSH in the laboratory reference range. Patients with a low TSH did not have an increased risk of any of these outcomes [hazards ratio: 1.1 (0.99-1.123), 1.13 (0.88-1.47), and 1.13 (0.92-1.39), respectively]. CONCLUSIONS: Patients with a high or suppressed TSH had an increased risk of cardiovascular disease, dysrhythmias, and fractures, but patients with a low but unsuppressed TSH did not. It may be safe for patients treated with T(4) to have a low but not suppressed serum TSH concentration.
CONTEXT: For patients on T(4) replacement, the dose is guided by serum TSH concentrations, but some patients request higher doses due to adverse symptoms. OBJECTIVE: The aim of the study was to determine the safety of patients having a low but not suppressed serum TSH when receiving long-term T(4) replacement. DESIGN: We conducted an observational cohort study, using data linkage from regional datasets between 1993 and 2001. SETTING: A population-based study of all patients in Tayside, Scotland, was performed. PATIENTS: All patients taking T(4) replacement therapy (n = 17,684) were included. MAIN OUTCOME MEASURES: Fatal and nonfatal endpoints were considered for cardiovascular disease, dysrhythmias, and fractures. Patients were categorized as having a suppressed TSH (<or=0.03 mU/liter), low TSH (0.04-0.4 mU/liter), normal TSH (0.4-4.0 mU/liter), or raised TSH (>4.0 mU/liter). RESULTS:Cardiovascular disease, dysrhythmias, and fractures were increased in patients with a high TSH: adjusted hazards ratio, 1.95 (1.73-2.21), 1.80 (1.33-2.44), and 1.83 (1.41-2.37), respectively; and patients with a suppressed TSH: 1.37 (1.17-1.60), 1.6 (1.10-2.33), and 2.02 (1.55-2.62), respectively, when compared to patients with a TSH in the laboratory reference range. Patients with a low TSH did not have an increased risk of any of these outcomes [hazards ratio: 1.1 (0.99-1.123), 1.13 (0.88-1.47), and 1.13 (0.92-1.39), respectively]. CONCLUSIONS:Patients with a high or suppressed TSH had an increased risk of cardiovascular disease, dysrhythmias, and fractures, but patients with a low but unsuppressed TSH did not. It may be safe for patients treated with T(4) to have a low but not suppressed serum TSH concentration.
Authors: Jihye Park; Brenna E Blackburn; Patricia A Ganz; Kerry Rowe; John Snyder; Yuan Wan; Vikrant Deshmukh; Michael Newman; Alison Fraser; Ken Smith; Kim Herget; Anne C Kirchhoff; Dev Abraham; Jaewhan Kim; Marcus Monroe; Mia Hashibe Journal: J Clin Endocrinol Metab Date: 2018-07-01 Impact factor: 5.958
Authors: Aubrey A Carhill; Danielle R Litofsky; Douglas S Ross; Jacqueline Jonklaas; David S Cooper; James D Brierley; Paul W Ladenson; Kenneth B Ain; Henry G Fein; Bryan R Haugen; James Magner; Monica C Skarulis; David L Steward; Mingxhao Xing; Harry R Maxon; Steven I Sherman Journal: J Clin Endocrinol Metab Date: 2015-07-14 Impact factor: 5.958
Authors: Jacqueline Jonklaas; Antonio C Bianco; Andrew J Bauer; Kenneth D Burman; Anne R Cappola; Francesco S Celi; David S Cooper; Brian W Kim; Robin P Peeters; M Sara Rosenthal; Anna M Sawka Journal: Thyroid Date: 2014-12 Impact factor: 6.568
Authors: Mone Zaidi; Maria I New; Harry C Blair; Alberta Zallone; Ramkumarie Baliram; Terry F Davies; Christopher Cardozo; James Iqbal; Li Sun; Clifford J Rosen; Tony Yuen Journal: J Endocrinol Date: 2018-03-19 Impact factor: 4.286