The Effectiveness of Thyroid Hormone Replacement Therapy on Heart Failure and Low-Triiodothyronine Syndrome: An Updated Systematic Review and Meta-analysis of Randomized Controlled Trials

ObjectiveThe purpose of this study was to conduct a systematic review and meta-analysis evaluating the role of thyroid hormone therapy in patients with heart failure and low-triiodothyronine syndrome.MethodsThe electronic databases PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, China Science and Technology Journal Database, Wanfang Database, and China Biology Medicine disc were systematically searched to identify eligible studies published before November 27, 2021. The mean difference was pooled for randomized controlled trials using a random-effects model.ResultsThe meta-analysis showed that thyroid hormone treatment improved the left ventricular ejection fraction (weighted mean difference [WMD] 5.61, 95% confidence interval [CI]: 4.38 to 6.85, I2 = 63.12%, P < 0.01). The cardiac output improved with thyroid hormone therapy (WMD 0.65, 95% CI: 0.42 to 0.89, I2 = 84.28%, P < 0.01). The early-to-late diastolic transmitral flow velocity in the thyroid hormone group was also improved compared to the control group (WMD 0.29, 95% CI: 0.15 to 0.42, I2 = 95.08%, P < 0.01). The left ventricular diastolic dysfunction was decreased with thyroid hormone treatment (WMD −5.17, 95% CI: −7.47 to −2.88, I2 = 90.18%, P < 0.01). The brain natriuretic peptide decreased with thyroid hormone treatment (standardized mean difference −1.49, 95% CI: −2.15 to −0.84, I2 = 90.18%, P < 0.01). Noradrenaline decreased with thyroid hormone therapy (WMD −349.86, 95% CI: −401.05 to −298.67, I2 = 0%, P < 0.01). Free triiodothyronine increased with thyroid hormone treatment (standardized mean difference 2.18, 95% CI: 0.75 to 2.60, I2 = 98.20%, P < 0.01).ConclusionThis meta-analysis showed that thyroid hormone replacement therapy was effective in patients with heart failure and low-triiodothyronine syndrome.