Serum thyroid-stimulating hormone concentration and morbidity from cardiovascular disease and fractures in patients on long-term thyroxine therapy
RW Flynn, SR Bonellie, RT Jung… - The Journal of …, 2010 - academic.oup.com
RW Flynn, SR Bonellie, RT Jung, TM MacDonald, AD Morris, GP Leese
The Journal of Clinical Endocrinology & Metabolism, 2010•academic.oup.comContext: For patients on T4 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 T4 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 …
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 T4 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 …
Abstract
Context: For patients on T4 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 T4 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 T4 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 (≤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 T4 to have a low but not suppressed serum TSH concentration.
Oxford University Press