Syamsundara Kiran A Naga, Pal Gopal Krushna, Pal Pravati, Kamalanathan Sadishkumar, Parija Subhash, Pinjar Mohammed Jaffer
Physiology, All India Institute of Medical Sciences, Kalyani, Kalyani, IND.
Physiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, IND.
Cureus. 2025 Mar 27;17(3):e81268. doi: 10.7759/cureus.81268. eCollection 2025 Mar.
Hypothyroidism, a common endocrine disorder, is linked to cardiovascular risks arising from autonomic imbalance and metabolic dysregulation. While overt hypothyroidism (OH) manifests distinct thyroid hormone abnormalities, subclinical hypothyroidism (SCH) presents milder hormonal changes. Levothyroxine therapy is widely used for thyroid function restoration, but its long-term effects on autonomic and cardiovascular health in OH remain understudied. This study investigates the therapeutic effects of six months of levothyroxine treatment on autonomic function and metabolic parameters in OH patients.
A follow-up study was conducted on OH patients receiving levothyroxine therapy. Participants with confounding cardiovascular comorbidities were excluded. Clinical assessments included autonomic function tests, metabolic profiling (lipid and thyroid parameters), and inflammatory/oxidative stress markers. Comparative analyses were performed against healthy controls.
Levothyroxine therapy effectively restored thyroid hormone levels in OH patients. Autonomic function tests demonstrated improved parasympathetic modulation and partial sympathovagal balance recovery, though residual autonomic irregularities persisted. Lipid profiles showed marked improvement but did not fully normalize compared to controls. Inflammatory and oxidative stress markers decreased significantly post-therapy, yet remained elevated relative to healthy individuals. Statistical modeling identified oxidative stress as a key contributor to autonomic dysfunction.
While levothyroxine normalized thyroid function and improved autonomic balance, incomplete resolution of metabolic and inflammatory abnormalities suggests persistent cardiovascular risks in OH patients after six months of therapy. The findings highlight the need for extended treatment durations to achieve comprehensive cardiovascular risk mitigation.
Despite therapeutic benefits, OH patients retain residual cardiovascular risks post-levothyroxine therapy, necessitating long-term monitoring. Future research should investigate optimal treatment durations and adjunct therapies to address persistent autonomic and metabolic dysfunction in this population.
甲状腺功能减退是一种常见的内分泌疾病，与自主神经失衡和代谢失调引起的心血管风险有关。虽然显性甲状腺功能减退（OH）表现出明显的甲状腺激素异常，但亚临床甲状腺功能减退（SCH）的激素变化较为轻微。左甲状腺素治疗广泛用于恢复甲状腺功能，但其对OH患者自主神经和心血管健康的长期影响仍有待研究。本研究调查了左甲状腺素治疗六个月对OH患者自主神经功能和代谢参数的治疗效果。
对接受左甲状腺素治疗的OH患者进行了一项随访研究。排除有混杂心血管合并症的参与者。临床评估包括自主神经功能测试、代谢谱分析（脂质和甲状腺参数）以及炎症/氧化应激标志物。与健康对照进行比较分析。
左甲状腺素治疗有效恢复了OH患者的甲状腺激素水平。自主神经功能测试显示副交感神经调节改善，部分交感迷走神经平衡恢复，尽管仍存在残留的自主神经异常。脂质谱显示有显著改善，但与对照组相比未完全正常化。治疗后炎症和氧化应激标志物显著下降，但相对于健康个体仍升高。统计模型确定氧化应激是自主神经功能障碍的关键因素。
虽然左甲状腺素使甲状腺功能正常化并改善了自主神经平衡，但代谢和炎症异常未完全解决，表明OH患者在治疗六个月后仍存在持续的心血管风险。研究结果强调需要延长治疗时间以全面降低心血管风险。
尽管有治疗益处，但OH患者在左甲状腺素治疗后仍存在残留的心血管风险，需要长期监测。未来的研究应调查最佳治疗时间和辅助治疗方法，以解决该人群中持续存在的自主神经和代谢功能障碍。
