Treating subclinical hypothyroidism patients with levothyroxine after an acute myocardial infarction (MI) does not improve left ventricular ejection fraction (LVEF), according to new findings published in JAMA. Any guidelines currently recommending such treatment, the authors wrote, should be reconsidered.
The Thyroxine in Acute Myocardial Infarction (ThyrAMI-2) trial tracked 95 subclinical hypothyroidism patients who had experienced an MI. The mean patient age was 63.5 years old, and they were treated at six different hospitals in the U.K. While 46 patients received levothyroxine treatment for one full year, the other 49 received a placebo for the same time period. MRI scans were used to assess cardiac volumes and function.
Overall, the mean LVEF improved from 51.3% to 53.8% for the levothyroxine group. For the placebo group, LVEF improved from 54% to 56.1%. Secondary outcomes—including left ventricular volume, infarct size, adverse events, depression and more—revealed no differences between the two groups.
“The results of this trial will help clinicians reconsider offering treatment with levothyroxine to tens of thousands of patients with subclinical hypothyroidism worldwide,” Salman Razvi, MD, the study’s corresponding author and a senior lecturer at Newcastle University, said in a statement. “The results of this trial demonstrate that there are no significant improvements for patients with heart attacks who are given levothyroxine. On this basis, screening for and subsequent treatment of subclinical hypothyroidism in patients who have had a heart attack to preserve or improve heart function is not justified.”
Razvi emphasized that nothing from the ThyrAMI-2 trial suggests levothyroxine should be a routine treatment for subclinical hypothyroidism.
“International guidelines should be amended to reflect this finding,” he said.
The full JAMA study is available here.
Michael has more than 16 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.