Objective:

Some studies have shown that metformin can reduce body weight. However, metformin has not been officially approved as a medicine for weight loss because its effect on different populations remains inconsistent. This meta-analysis aimed to summarize the weight loss effect of metformin quantitatively.

Method:

The randomized controlled and high-quality case-control trials of metformin monotherapy in obesity treatment were eligible. Baseline body mass index (BMI) was chosen as a self-control to compare the changes in BMI of different populations before and after treatment. All changes were calculated as differences between the final and initial BMI values (with negative values indicating a decrease). Results were presented as weighted mean difference (WMD) with a 95% confidence interval (CI 95%). Subgroup analysis was performed based on baseline BMI, age, daily dose, and duration of medication.

Results:

A total of 21 trials (n = 1004) were included, and the meta-analysis of metformin treatment in different populations showed that metformin has a modest reduction in the BMI of included participants (WMD −0.98; 95% CI, −1.25 to −0.72), and the reduction of BMI was most significant in the simple obesity population (WMD −1.31; 95% CI, −2.07 to −0.54). The subgroup analysis showed that metformin treatment significantly reduced BMI in obesity patients with a BMI >35kg/m² (WMD −1.12; 95% CI, −1.84 to −0.39) compared with before treatment. BMI in the high dose group decreased by 1.01 units (WMD−1.01; 95% CI, −1.29 to −0.73) and BMI did not continue to decrease significantly after treatment of more than 6 months.

Conclusion:

Patients treated with metformin experienced about a one-unit reduction in BMI at the end of treatment. But whether this decreased value produced enough weight loss (5% of baseline body weight) to qualify as a “weight loss drug” as current guidelines require, requires larger specific randomized control trials.

中文翻译：

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二甲双胍在不同人群肥胖治疗中的作用：荟萃分析。

 客观的：

一些研究表明二甲双胍可以减轻体重。然而，二甲双胍尚未被正式批准作为减肥药物，因为它对不同人群的效果仍然不一致。本荟萃分析旨在定量总结二甲双胍的减肥效果。

 方法：

二甲双胍单药治疗肥胖症的随机对照和高质量病例对照试验是合格的。选择基线体重指数（BMI）作为自我对照，比较不同人群治疗前后BMI的变化。所有变化均计算为最终 BMI 值与初始 BMI 值之间的差异（负值表示下降）。结果以加权平均差 (WMD) 形式呈现，置信区间为 95% (CI 95%)。根据基线 BMI、年龄、每日剂量和用药持续时间进行亚组分析。

 结果：

总共纳入了 21 项试验（ n = 1004），不同人群中二甲双胍治疗的荟萃分析表明，二甲双胍可适度降低纳入参与者的 BMI（WMD -0.98；95% CI，-1.25 至 - 0.72），BMI 的降低在单纯性肥胖人群中最为显着（WMD -1.31；95% CI，-2.07 至 -0.54）。亚组分析显示，与治疗前相比，二甲双胍治疗显着降低了BMI>35kg/m ²的肥胖患者的BMI（WMD -1.12；95% CI，-1.84至-0.39）。高剂量组BMI下降1.01单位（WMD−1.01；95% CI，−1.29至−0.73），且治疗6个月以上后BMI并未继续显着下降。

 结论：

使用二甲双胍治疗的患者在治疗结束时体重指数降低了约一个单位。但这种降低的值是否能产生足够的体重减轻（基线体重的 5%），从而达到当前指南要求的“减肥药物”的资格，需要更大规模的特定随机对照试验。