Effectiveness and Safety of Thyroid Hormone Therapy in Patients with Dilated Cardiomyopathy: A Systematic Review and Meta-analysis of RCTs

Background Previous research demonstrated that short-term treatment of dilated cardiomyopathy with thyroid hormones exerted beneficial hemodynamic effects when added to standard anti-heart failure therapy, but it remains debatable whether thyroid hormones can be used to treat dilated cardiomyopathy. Therefore, we conducted a meta-analysis to evaluate the effectiveness and safety of thyroid hormone treatment in patients with dilated cardiomyopathy. Methods The Cochrane Clinical Trials Registry database, PubMed, Embase, Chinese Biomedical Literature Database, China Academic Journals full-text database, Wanfang Database, China Science and Technology Journal Database, and Clinical Trials.gov were screened through 15 October, 2021. Randomized controlled clinical trials were selected based on study inclusion criteria. Two independent reviewers extracted the data and assessed study bias using the Cochrane risk of bias tool. For the data synthesis, the weighted mean difference was calculated using baseline and post-thyroid hormone treatment data. Random-effects models were used for the meta-analysis. The primary outcomes were left ventricular ejection fraction after a minimum follow-up of 1 week and adverse events. Results Ten of the 1149 published reports met the inclusion criteria (N = 608 randomized individuals). After reasonable use of thyroid hormone therapy, left ventricular ejection fraction increased (weighted mean difference, 3.94; 95% confidence interval 3.06-4.81; I-2 = 0.00%), cardiac output increased, and left ventricular end-diastolic diameter decreased, but left ventricular mass index and thyroid function were unaffected. Adverse events were reported in the intervention group of two studies. The ten studies demonstrated a low risk of bias. Conclusions Adding thyroid hormones to conventional anti-heart failure treatment in patients with DCM appears to be an effective and well tolerated therapeutic option.