{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,24]],"date-time":"2026-01-24T13:35:37Z","timestamp":1769261737918,"version":"3.49.0"},"reference-count":38,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,1,23]],"date-time":"2026-01-23T00:00:00Z","timestamp":1769126400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Endocrinol."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>While levothyroxine (L-T4) therapy is standard for hypothyroidism, its direct effects on specific echocardiographic parameters of cardiac function remain underexplored in comprehensive meta-analyses.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We systematically searched multiple databases up to June 2025 for randomized controlled trials and prospective cohort studies assessing L-T4 therapy on echocardiographic parameters in hypothyroid adults. Data on cardiac indices, intervention details, follow-up, and disease types were extracted. Risk of bias was assessed using standard tools. A random-effects model calculated mean differences (MDs) and assessed heterogeneity. Subgroup analyses evaluated treatment type, follow-up duration, and underlying disease.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Six studies (2 RCTs and 4 cohort studies) were included. Overall, L-T4 intervention did not significantly alter the LV Tei Index (MD = 0.0214, 95% CI: -0.0294 to 0.0722, p=0.4083) or LVEF (MD = -0.2258, 95% CI: -0.8990 to 0.4475, p=0.5110). However, a statistically significant increase in Mitral E velocity (MD = -0.0646, 95% CI: -0.1138 to -0.0154, p=0.0100) and Mitral A velocity (MD\u00a0= -0.0646, 95% CI: -0.1138 to -0.0154, p=0.0100) was observed. Subgroup analyses for LV Tei Index showed a statistically significant improvement in the 12-month follow-up subgroup (MD = 0.0672, 95% CI: 0.0161 to 0.1183) and in congenital hypothyroidism (MD = 0.0300, 95% CI: 0.0044 to 0.0556). For LVEF, a statistically significant increase was found in the 12-week follow-up subgroup (MD = -7.9300, 95% CI: -14.4844 to -1.3756) and the overt hypothyroidism subgroup (MD = -7.9300, 95% CI: -14.4844 to -1.3756). The effect of L-T4 on Mitral E and Mitral A velocities varied significantly across disease types (p=0.0304 for both), with a significant increase noted in the congenital hypothyroidism subgroup for both. No significant change was observed in the E\/A ratio (MD\u00a0=\u00a0-0.0058, 95% CI: -0.0360 to 0.0244, p=0.7058), with no significant subgroup differences.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>L-T4 exerts differential effects on echocardiographic measures of cardiac function, with specific improvements influenced by follow-up duration and underlying etiology.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Systematic Review Registration<\/jats:title>\n                    <jats:p>\n                      <jats:ext-link>https:\/\/www.crd.york.ac.uk\/PROSPERO\/view\/<\/jats:ext-link>\n                      , CRD420251274519.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fendo.2025.1708811","type":"journal-article","created":{"date-parts":[[2026,1,23]],"date-time":"2026-01-23T06:44:12Z","timestamp":1769150652000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Evaluating cardiac echocardiographic changes with levothyroxine in hypothyroid patients: a systematic review and meta-analysis"],"prefix":"10.3389","volume":"16","author":[{"given":"Yanyan","family":"Li","sequence":"first","affiliation":[{"name":"Air Force Medical Center, PLA","place":["Beijing, China"]},{"name":"People\u2019s Liberation Army Air Force Special Medical Center","place":["Beijing, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2026,1,23]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1080\/20009666.2019.1625704","article-title":"The effect of levothyroxine treatment in individuals with subclinical hypothyroidism on surrogate markers of atherosclerosis: a meta-analysis of randomized controlled trials","volume":"9","author":"Swaid","year":"2019","journal-title":"J Community Hosp Internal Med Perspect"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.3389\/fendo.2018.00454","article-title":"Effect of levothyroxine on blood pressure in patients with subclinical hypothyroidism: A systematic review and meta-analysis","volume":"9","author":"He","year":"2018","journal-title":"Front Endocrinol"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.1016\/j.cpcardiol.2023.102204","article-title":"Systematic review and meta-analysis of levothyroxine effect on blood pressure in patients with subclinical hypothyroidism","volume":"49","author":"Darouei","year":"2024","journal-title":"Curr Problems Cardiol"},{"key":"B4","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1111\/cen.13338","article-title":"The lipid-lowering effect of levothyroxine in patients with subclinical hypothyroidism: A systematic review and meta-analysis of randomized controlled trials","volume":"87","author":"Li","year":"2017","journal-title":"Clin Endocrinol"},{"key":"B5","doi-asserted-by":"publisher","first-page":"62","DOI":"10.1007\/s12020-020-02484-1","article-title":"Meta-analytic evidence for increased low-grade systemic inflammation and oxidative stress in hypothyroid patients. 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