Li Xiang, Wang Yupeng, Guan Qingbo, Zhao Jiajun, Gao Ling
Department of Endocrinology and Metabolism, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China.
Scientific Center, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China.
Clin Endocrinol (Oxf). 2017 Jul;87(1):1-9. doi: 10.1111/cen.13338. Epub 2017 Apr 24.
Dyslipidaemia is common in patients with subclinical hypothyroidism (SCH). To date, there is no universal agreement regarding the lipid-lowering effect of substitution treatment with L-T4 in patients with SCH. We aimed to clarify the effect by conducting this systematic review and meta-analysis of randomized controlled trials (RCTs).
We systematically searched PubMed, the Cochrane Library, ClinicalTrials.gov and EMBASE for RCTs comparing substitution treatment to placebo treatment or observation. We focused on the primary outcomes of changes from baseline of total, low-density lipoprotein and high-density lipoprotein cholesterol (TC, LDL-C and HLD-C) and triglycerides. Subgroup analyses were performed, assessing the effect of treatment duration, disease severity and ethnicity on the occurrence of discrepancy.
Twelve trials, with 940 participants, were eligible for analysis. Compared with the control group, levothyroxine substitution yielded a mean reduction in TC (-0.29 mmol/L, [-0.42 to -0.16]) and LDL-C (-0.22 mmol/L, [-0.36 to -0.09]), with no significant effects on HDL-C (-0.04 mmol/L, [-0.08 to 0.01]) or triglycerides (-0.04 mmol/L, [-0.08 to 0.00]). Trials in which only patients with mild SCH (thyrotropin <10 mIU/L) were enrolled showed equivalent effects. The lowering effects were weaker, but still significant, in long-term treatment (>6 months) compared with short-term treatment (≤6 months) for TC (-0.19 mmol/L [-0.35, -0.03] vs -0.50 mmol/L [-0.68, -0.31], P=.047) and LDL-C (-0.09 mmol/L [-0.16, -0.02] vs -0.46 mmol/L [-0.68, -0.25], P=.006).
Levothyroxine treatment has clear benefits on TC and LDL-C in SCH patients, including those with mild SCH.
血脂异常在亚临床甲状腺功能减退症（SCH）患者中很常见。迄今为止，关于SCH患者使用左甲状腺素（L-T4）替代治疗的降脂效果尚无普遍共识。我们旨在通过对随机对照试验（RCT）进行系统评价和荟萃分析来阐明其效果。
我们系统检索了PubMed、Cochrane图书馆、ClinicalTrials.gov和EMBASE，以查找比较替代治疗与安慰剂治疗或观察的RCT。我们重点关注总胆固醇、低密度脂蛋白胆固醇和高密度脂蛋白胆固醇（TC、LDL-C和HDL-C）以及甘油三酯相对于基线变化的主要结局。进行了亚组分析，评估治疗持续时间、疾病严重程度和种族对差异发生的影响。
12项试验，共940名参与者，符合分析条件。与对照组相比，左甲状腺素替代治疗使TC（-0.29 mmol/L，[-0.42至-0.16]）和LDL-C（-0.22 mmol/L，[-0.36至-0.09]）平均降低，对HDL-C（-0.04 mmol/L，[-0.08至0.01]）或甘油三酯（-0.04 mmol/L，[-0.08至0.00]）无显著影响。仅纳入轻度SCH（促甲状腺激素<10 mIU/L）患者的试验显示出等效效果。与短期治疗（≤6个月）相比，长期治疗（>6个月）时TC（-0.19 mmol/L [-0.35，-0.03] 对 -0.50 mmol/L [-0.68，-0.31]，P = 0.047）和LDL-C（-0.09 mmol/L [-0.16，-0.02] 对 -0.46 mmol/L [-0.68，-0.25]，P = 0.006）的降低效果较弱，但仍具有统计学意义。
左甲状腺素治疗对SCH患者的TC和LDL-C有明显益处，包括轻度SCH患者。
