Population and Behavioural Science Division, School of Medicine, University of St Andrews, St Andrews, Scotland, United Kingdom.
PLoS One. 2022 May 19;17(5):e0268070. doi: 10.1371/journal.pone.0268070. eCollection 2022.
This umbrella review summarises and compares synthesised evidence on the impact of subclinical hypothyroidism and its management on long-term clinical outcomes.
We conducted comprehensive searches on MEDLINE, EMBASE, Scopus, Web of Science, Cochrane Database of Systematic Reviews, JBI Evidence Synthesis, the PROSPERO register, Epistemonikos Database and PDQ Evidence from inception to February and July 2021 using keywords on subclinical hypothyroidism, treatment with levothyroxine, monitoring and primary outcomes (all-cause mortality, cardiovascular events, stroke, frailty fractures and quality of life). Only systematic reviews and meta-analyses on adult patient populations were considered. Study selection, data extraction and quality appraisal using AMSTAR-2 were done independently by two reviewers and discrepancies were resolved through discussion. Overlap across the selected reviews was also assessed, followed by a narrative synthesis of findings.
A total of 763 studies were identified from literature searches; 20 reviews met inclusion criteria. Methodological quality ratings were high (n = 8), moderate (n = 7), and low (n = 5), but no reviews were excluded on this basis. Though there was slight overlap across all reviews, some pairwise comparisons had high corrected covered area scores. Compared to euthyroidism, untreated subclinical hypothyroidism was associated with a higher risk of cardiovascular events or death if Thyroid Stimulating Hormone was above 10mIU/L at baseline. Treatment was associated with a lower risk of death from all causes for patients younger than 70 years and possibly better cognitive and quality of life scores than untreated individuals. Evidence on the risk of strokes and fractures was inconclusive.
In the long term, treatment of subclinical hypothyroidism may be beneficial for some patient groups. However, the findings of this review are negatively impacted by the relative sparseness and poor quality of available evidence. Additional large and adequately powered studies are needed to investigate this topic further.
PROSPERO (CRD42021235172).
本综述总结并比较了亚临床甲状腺功能减退症及其治疗对长期临床结局的影响的综合证据。
我们使用亚临床甲状腺功能减退症、左甲状腺素治疗、监测和主要结局（全因死亡率、心血管事件、中风、脆性骨折和生活质量）的关键词，在 MEDLINE、EMBASE、Scopus、Web of Science、Cochrane 系统评价数据库、JBI 证据综合、PROSPERO 注册、Epistemonikos 数据库和 PDQ 证据从成立到 2021 年 2 月和 7 月进行了全面搜索。仅考虑针对成年患者群体的系统评价和荟萃分析。两名评审员独立进行研究选择、数据提取和 AMSTAR-2 质量评估，通过讨论解决分歧。还评估了所选综述之间的重叠，并对结果进行了叙述性综合。
从文献搜索中总共确定了 763 项研究；20 项综述符合纳入标准。方法学质量评分高（n=8）、中等（n=7）和低（n=5），但没有因此排除任何综述。尽管所有综述都有轻微重叠，但一些两两比较的校正覆盖面积得分较高。与甲状腺功能正常相比，如果基线时甲状腺刺激激素（TSH）超过 10mIU/L，未经治疗的亚临床甲状腺功能减退症与心血管事件或死亡风险增加相关。对于年龄小于 70 岁的患者，治疗与全因死亡率降低相关，并且与未经治疗的个体相比，认知和生活质量评分可能更好。关于中风和骨折风险的证据尚无定论。
从长远来看，亚临床甲状腺功能减退症的治疗可能对某些患者群体有益。然而，本综述的结果受到现有证据相对稀疏和质量差的负面影响。需要进一步开展更大规模和足够效力的研究来进一步探讨这个问题。
PROSPERO（CRD42021235172）。
