Log in to MyACC
Effect of Levothyroxine on LVEF in Subclinical Hypothyroidism and AMI
Quick Takes
- Treatment with levothyroxine for 52 weeks did not significantly improve LV function in patients with mild subclinical hypothyroidism presenting with AMI.
- These data suggest that screening for and subsequent treatment of subclinical hypothyroidism in patients with AMI to preserve LV function is not warranted.
- It is not known whether treating individuals with more severe disease (thyrotropin >10.0 mU/L) may or may not be beneficial, as the current trial did not include those patients.
Study Questions:
What is the effect of levothyroxine treatment on left ventricular (LV) function in patients with acute myocardial infarction (AMI) and subclinical hypothyroidism?
Methods:
The investigators conducted a double-blind, randomized clinical trial in six hospitals in the United Kingdom. Patients with AMI including ST-segment elevation (STEMI) and non–ST-segment elevation (NSTEMI) were recruited between February 2015 and December 2016, with the last participant being followed up in December 2017. Levothyroxine treatment (n = 46) commencing at 25 μg titrated to aim for serum thyrotropin levels between 0.4 and 2.5 mU/L or identical placebo (n = 49), both provided in capsule form, once daily for 52 weeks was administered. The primary outcome measure was LV ejection fraction (LVEF) at 52 weeks, assessed by magnetic resonance imaging, adjusted for age, sex, type of AMI, affected coronary artery territory, and baseline LVEF. Secondary measures were LV volumes, infarct size (assessed in a subgroup [n = 60]), adverse events, and patient-reported outcome measures of health status, health-related quality of life, and depression. The relationship of clinical and treatment variables with outcomes was assessed by multiple linear regression analysis.
Results:
Among the 95 participants randomized, the mean (standard deviation [SD]) age was 63.5 (9.5) years, 72 (76.6%) were men, and 65 (69.1%) had STEMI. The median serum thyrotropin level was 5.7 mU/L (interquartile range, 4.8-7.3 mU/L) and the mean (SD) free thyroxine level was 1.14 (0.16) ng/dl. The primary outcome measurements at 52 weeks were available in 85 patients (89.5%). The mean LVEF at baseline and at 52 weeks was 51.3% and 53.8%, respectively, in the levothyroxine group compared with 54.0% and 56.1%, respectively, in the placebo group (adjusted difference in groups, 0.76%; 95% confidence interval, −0.93% to 2.46%; p = 0.37). None of the six secondary outcomes showed a significant difference between the levothyroxine and placebo treatment groups. There were 15 (33.3%) and 18 (36.7%) cardiovascular adverse events in the levothyroxine and placebo groups, respectively.
Conclusions:
The authors concluded that treatment with levothyroxine, compared with placebo, did not significantly improve LVEF after 52 weeks among patients with subclinical hypothyroidism and AMI.
Perspective:
This double-blind, randomized, placebo-controlled trial reports that treatment with levothyroxine for 52 weeks did not significantly improve LV function in patients with mild subclinical hypothyroidism presenting with AMI. These data suggest that screening for and subsequent treatment of subclinical hypothyroidism in patients with AMI to preserve LV function is not warranted. It is not known whether treating individuals with more severe disease (thyrotropin >10.0 mU/L) may or may not be beneficial, as the current trial did not include those patients.
Clinical Topics: Acute Coronary Syndromes, Cardiovascular Care Team, Diabetes and Cardiometabolic Disease, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Prevention, Stable Ischemic Heart Disease, Vascular Medicine, Acute Heart Failure, Magnetic Resonance Imaging, Chronic Angina
Keywords: Acute Coronary Syndrome, Depression, Heart Failure, Hypothyroidism, Magnetic Resonance Imaging, Metabolic Syndrome, Myocardial Infarction, Myocardial Ischemia, Primary Prevention, Quality of Life, ST Elevation Myocardial Infarction, Stroke Volume, Thyroid Function Tests, Thyroid Hormones, Thyrotropin, Thyroxine, Ventricular Function, Left
< Back to Listings
