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The lipid‐lowering effect of levothyroxine in patients with subclinical hypothyroidism: A systematic review and meta‐analysis of randomized controlled trials
Author(s) -
Li Xiang,
Wang Yupeng,
Guan Qingbo,
Zhao Jiajun,
Gao Ling
Publication year - 2017
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/cen.13338
Subject(s) - medicine , levothyroxine , randomized controlled trial , subclinical infection , gastroenterology , placebo , lipid profile , subgroup analysis , cochrane library , meta analysis , endocrinology , cholesterol , hormone , alternative medicine , pathology
Summary Objectives 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 ( RCT s). Design We systematically searched PubMed, the Cochrane Library, ClinicalTrials.gov and EMBASE for RCT s 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. Results 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). Conclusions Levothyroxine treatment has clear benefits on TC and LDL ‐C in SCH patients, including those with mild SCH .