Department of Endocrinology and Metabolism, Institute of Endocrine, NHC Key Laboratory of Diagnosis and Treatment of Thyroid Diseases, The First Hospital of China Medical University, Shenyang, 110001, People's Republic of China.
BMC Endocr Disord. 2024 Oct 25;24(1):224. doi: 10.1186/s12902-024-01754-7.
Subclinical hypothyroidism (SCH) is characterized by elevated levels of thyroid hormone (TSH) and normal levels of free thyroxine (FT4). The outcomes of SCH patients are crucial for determining treatment plans; therefore, our aim is to summarize the existing prospective studies to understand the changes in thyroid function over time in SCH patients and the factors influencing these changes, providing references for clinical diagnosis and treatment.
We searched PubMed, Embase, Cochrane Library, and Web of Science for prospective follow-up studies on natural outcomes of SCH published until September 2024. Results are presented as the overall risk ratio (RR) and 95% confidence intervals (CI).
We reviewed 8 prospective follow-up studies involving 1,859 individuals and extracted data from them for a meta-analysis. We found that when TSH levels are ≥ 10 mU/L, patients with SCH are more likely to progress to overt hypothyroidism (OH) (RR11.38, 95%CI 4.98-26.03, P<0.001) and were less likely to return to normal TSH levels (RR 0.20, 95%CI 0.09-0.42, P<0.001) compared to patients with TSH between 4.5 and 9.9 mU/L. In addition, patients who test positive for thyroid peroxidase antibodies (TPOAb) are more likely to progress to OH (RR 2.53, 95% CI 1.86-3.44, P < 0.001) and less likely to return to euthyroidism (RR 0.68, 95% CI 0.60-0.76, P < 0.001) compared to TPOAb-negative patients.
The results indicated that a large proportion of patients diagnosed with SCH will return to normal TSH levels or maintain SCH. Additionally, patients with TSH levels ≥ 10 mU/L or positive for TPOAb are more likely to experience progression and should be closely monitored. However, we did not find any gender differences in the natural outcome of SCH.
亚临床甲状腺功能减退症（SCH）的特点是甲状腺激素（TSH）水平升高，游离甲状腺素（FT4）水平正常。SCH 患者的结局对于确定治疗方案至关重要；因此，我们的目的是总结现有的前瞻性研究，以了解 SCH 患者甲状腺功能随时间的变化以及影响这些变化的因素，为临床诊断和治疗提供参考。
我们检索了 PubMed、Embase、Cochrane 图书馆和 Web of Science 中截至 2024 年 9 月发表的关于 SCH 自然结局的前瞻性随访研究。结果以总风险比（RR）和 95%置信区间（CI）表示。
我们回顾了 8 项前瞻性随访研究，共纳入 1859 名患者，并从中提取数据进行荟萃分析。我们发现，当 TSH 水平≥10 mU/L 时，SCH 患者更有可能进展为显性甲状腺功能减退症（OH）（RR11.38，95%CI 4.98-26.03，P<0.001），而更不可能恢复正常 TSH 水平（RR 0.20，95%CI 0.09-0.42，P<0.001）与 TSH 水平在 4.5 至 9.9 mU/L 之间的患者相比。此外，甲状腺过氧化物酶抗体（TPOAb）阳性的患者更有可能进展为 OH（RR 2.53，95%CI 1.86-3.44，P<0.001），而更不可能恢复为甲状腺功能正常（RR 0.68，95%CI 0.60-0.76，P<0.001）与 TPOAb 阴性患者相比。
结果表明，很大一部分诊断为 SCH 的患者将恢复正常 TSH 水平或维持 SCH。此外，TSH 水平≥10 mU/L 或 TPOAb 阳性的患者更有可能出现进展，应密切监测。然而，我们没有发现 SCH 自然结局存在任何性别差异。
