Effect of l-thyroxine administration before breakfast vs at bedtime on hypothyroidism: A meta-analysis.

PURPOSE: To compare the effects of l-thyroxine (L-T4) administration before breakfast and administration at bedtime on hypothyroidism.

METHODS: The PubMed, EMBASE, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI) and Wanfang databases were searched to identify relevant articles. All prospective or randomized controlled studies (RCTs) comparing L-T4 administration before breakfast to the administration at bedtime in patients with hypothyroidism were included in the analysis.

RESULTS: Initially, 2884 articles were retrieved from the databases, and 10 articles were included in the quantitative analysis. The effect of L-T4 administration before breakfast compared with administration at bedtime had no statistically significant association with hormone thyrotropin (TSH) (Standardized mean differences [SMD] = 0.09, 95% confidence intervals (CI): -0.12, 0.30; P = .39), or free triiodothyronine (FT3) (SMD=-0.19, 95% CI: -0.53, 0.15; P = .28) in patients with hypothyroidism. However, the result of FT4 level was favourable for L-T4 bedtime administration group (SMD=-0.27, 95% CI: -0.52, -0.02; P = .03).

CONCLUSION: Our meta-analysis revealed that L-T4 administration at bedtime is as effective as administration before breakfast for patients with hypothyroidism. Taking L-T4 at bedtime may be an attractive option for patients with hypothyroidism.