Effect of metformin intervention on circulating irisin levels in polycystic ovary syndrome: a systematic review and collaborative meta-analysis

Abstract

Background

Irisin is an adipo-myokine with potential implications in metabolic disorders such as polycystic ovary syndrome (PCOS). Despite of a strong evidence showing increased irisin level in PCOS, there is no conclusive evidence on the effect of metformin intervention on circulatory irisin in PCOS.

Aim

The aim of this meta-analysis was to compare the circulatory (serum/plasma) irisin levels before and after metformin intervention in subjects with PCOS.

Methods

Relevant studies were retrieved by online database and manual searching. The standardized mean differences (SMDs) with 95% confidence intervals (CIs) were obtained by a random-effects meta-analysis. A one-study leave-out sensitivity analysis was conducted to validate the overall obtained results.

Results

A total of five observations were included in this meta-analysis. The results based on random effects meta-analysis indicated that irisin levels were significantly decreased after metformin intervention as compared to the baseline pretreatment levels in PCOS (SMD: −1.00, 95% CI: −1.60 to −0.41, Z: 3.29, p = .001). The sensitivity analysis leaving-out a particular observation at a time and repeating the meta-analysis validated the robustness of the overall finding suggesting the significant effect of metformin treatment on irisin levels in PCOS.

Conclusion

Circulating irisin levels were significantly decreased upon metformin intervention in PCOS patients. The higher pretreatment irisin levels in PCOS may recede once the altered metabolic state is restored upon metformin intervention. Well-designed randomized trials with large sample sizes are warranted to further substantiate the reported evidence reported and to establish the possible mechanisms.

二甲双胍干预对多囊卵巢综合征患者循环鸢尾素水平的影响：一项系统回顾及协作meta分析

背景：Irisin是一种脂肪-肌肉因子, 在多囊卵巢综合征( PCOS )等代谢性疾病中具有潜在的意义。尽管有强有力的证据显示PCOS患者鸢尾素水平升高, 但二甲双胍干预对PCOS患者循环鸢尾素的影响尚无定论。

目的：该meta分析的目的是比较PCOS患者二甲双胍干预前后循环(血清/血浆)鸢尾素水平。

方法：相关研究通过在线数据库和手动检索获取。通过随机效应meta分析得出标准化均数差( SMDs )及其95 %置信区间。为了验证整体结果, 进行了逐一敏感性分析。

结果： Meta分析共纳入5项观察性研究。基于随机效应的meta分析结果显示：二甲双胍干预后PCOS患者鸢尾素水平较基线水平明显降低（SMD：-1.00,95 % CI：-1.60∼-0.41 , Z：3.29 , p=001）。敏感性分析每次剔除一项观察性研究后重复进行meta分析验证了整体研究结果的稳定性, 提示二甲双胍治疗对PCOS患者鸢尾素水平有显著影响。

结论：二甲双胍干预后PCOS患者循环鸢尾素水平明显降低。二甲双胍干预后代谢状态改变, PCOS患者预处理前较高的鸢尾素水平可能会下降。有必要进行设计良好的大样本随机试验以进一步证实已报道的证据并建立可能的机制。

Keywords:

• Irisin
• meta-analysis
• metformin
• polycystic ovary syndrome

Acknowledgments

Dr. S.R. Varikasuvu specially acknowledges Bhairavi Sisters (Sahasra and Aagneya) for the time I could not give them during this work as it was performed before 8 am and after 6 pm from its initiation to completion.

Disclosure statement

No potential conflict of interest was reported by the author(s). The costs involved in the conduction of this systematic review and meta-analysis were borne by the authors themselves.