Amouzegar A, Dehghani M, Abdi H, Mehran L, Masoumi S, Azizi F
Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, P.O. Box 19395-4763, Tehran, Iran.
Prevention of Metabolic Disorders Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
J Endocrinol Invest. 2022 Dec;45(12):2353-2364. doi: 10.1007/s40618-022-01876-6. Epub 2022 Aug 4.
The significance of subclinical hypothyroidism (SCH) is largely due to its potential risk for developing overt hypothyroidism (OH). Investigations are still exploring predictive factors contributing to the progression of SCH to OH, particularly in patients with mildly elevated serum thyrotropin (TSH). We aimed to clarify the natural history of SCH and the predictive factors of its progression, based on the grade of SCH severity.
This study was conducted within the framework of the Tehran Thyroid Study (TTS), in which 5783 individuals aged ≥ 20 years were followed. After applying exclusion criteria, data of 270 SCH subjects remained for the analysis. Thyroid function tests were assessed at baseline and every 3 years.
Of 270 participants with SCH, 239 (88.5%) had TSH level between 5.06 and 10 mU/L, and 31 (11.4%) had TSH ≥ 10 mU/L. During a median follow-up of 10 years, 40% had TSH within the reference range, 44% maintained elevated TSH, and 16% had added low T4 to the elevated TSH. The annual incidence rate of progression to OH was 22.3 (16.5-101.9) per 1000 person-years [18 (12.6-25.6) for those with TSH 5.07-9.9 mU/L and 57.8 (22.8-101.9) for patients with TSH ≥ 10 mU/L per 1000 person-years (P = 0.001)]. After adjusting age, sex, body mass index (BMI), thyroid peroxidase antibody (TPOAb), and serum TSH, only TPOAb positivity (HR: 2.31; 95% CI 1.10-4.83, P = 0.026) and baseline TSH level ≥ 10 mU/L (HR: 5.14; 95% CI 2.14-12.3, P < 0.001) remained as predictors for development of OH. In patients with TSH 5.07-9.9 mU/L, TPOAb positivity was associated with an increased risk of OH (HR: 2.41; 95% CI 1.10-5.30, P = 0.027). However, in patients with TSH ≥ 10 mU/L, TPOAb positivity was not a predictor (P = 0.49).
TPOAb and not TSH are associated with the development of OH in individuals with serum TSH below 10 mU/L, and follow-up at regular intervals is recommended in TPOAb-positive individuals with TSH between 5 and 10 mU/L.
亚临床甲状腺功能减退症（SCH）的重要性很大程度上在于其发展为临床显性甲状腺功能减退症（OH）的潜在风险。研究仍在探索导致SCH进展为OH的预测因素，尤其是血清促甲状腺激素（TSH）轻度升高的患者。我们旨在根据SCH严重程度分级阐明SCH的自然病程及其进展的预测因素。
本研究在德黑兰甲状腺研究（TTS）框架内进行，对5783名年龄≥20岁的个体进行随访。应用排除标准后，270名SCH受试者的数据留作分析。在基线和每3年时评估甲状腺功能测试。
270名SCH参与者中，239名（88.5%）的TSH水平在5.06至10 mU/L之间，31名（11.4%）的TSH≥10 mU/L。在中位随访10年期间，40%的患者TSH在参考范围内，44%的患者TSH持续升高，16%的患者在TSH升高的基础上出现低T4。进展为OH的年发病率为每1000人年22.3（16.5 - 101.9）[TSH为5.07 - 9.9 mU/L的患者为每1000人年18（12.6 - 25.6），TSH≥10 mU/L的患者为每1000人年57.8（22.8 - 101.9）（P = 0.001）]。在调整年龄、性别、体重指数（BMI）、甲状腺过氧化物酶抗体（TPOAb）和血清TSH后，仅TPOAb阳性（HR：2.31；95%CI 1.10 - 4.83，P = 0.026）和基线TSH水平≥10 mU/L（HR：5.14；95%CI 2.14 - 12.3，P < 0.001）仍然是OH发生的预测因素。在TSH为5.07 - 9.9 mU/L的患者中，TPOAb阳性与OH风险增加相关（HR：2.41；95%CI 1.10 - 5.30，P = 0.027）。然而，在TSH≥10 mU/L的患者中，TPOAb阳性不是预测因素（P = 0.49）。
对于血清TSH低于10 mU/L的个体，与OH发生相关的是TPOAb而非TSH，建议对TSH在5至10 mU/L之间的TPOAb阳性个体进行定期随访。
