OBJECTIVE To investigate the factors that are associated with the effect of metformin on endothelial dysfunction in polycystic ovary syndrome (PCOS). PATIENTS AND METHODS From March 24, 2014, to November 18, 2016, 48 women with PCOS were randomly assigned to 1500 mg/d of metformin (N=29) or no treatment (N=13) for 3 months; 42 patients (29 in the initial treatment group and 13 in the no treatment group) completed the study. Study variables were measured at baseline and after 3 months. Participants who did not receive metformin initially were then treated with metformin for another 3 months, and study variables were measured again. Endothelial function was measured as reactive hyperemia-peripheral arterial tonometry (RH-PAT) from the index finger. RESULTS The age and baseline endothelial function (mean ± SD) of the participants were 32.7±6.9 years and 1.8±0.5, respectively. No notable change was observed in endothelial function after 3 months with metformin compared with no treatment. However, after stratifying participants who received metformin based on baseline endothelial function, there was a significant improvement following metformin treatment in participants with abnormal baseline endothelial function (1.3±0.3 vs 1.7±0.3; P<.001) but not in those with normal baseline endothelial function (2.1±0.4 vs 2.0±0.5; P=.11). CONCLUSION Metformin improves endothelial function in women with PCOS and endothelial dysfunction independent of changes in glucose metabolism, dyslipidemia, or presence of prediabetes. Metformin has a direct effect on endothelial function in PCOS, and measurement of endothelial function can stratify and follow response to metformin treatment in PCOS. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT02086526.

中文翻译：

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二甲双胍对多囊卵巢综合征微血管内皮功能的影响。

目的探讨与二甲双胍对多囊卵巢综合征（PCOS）内皮功能障碍的影响有关的因素。患者与方法从2014年3月24日至2016年11月18日，将48例PCOS患者随机分配为1500 mg / d的二甲双胍（N = 29）或不接受治疗（N = 13）3个月；42例患者（初始治疗组中29例，未治疗组中13例）完成了研究。在基线和3个月后测量研究变量。最初未接受二甲双胍治疗的参与者再接受二甲双胍治疗3个月，并再次测量研究变量。内皮功能通过食指从反应性充血-外周动脉眼压（RH-PAT）进行测量。结果参与者的年龄和基线内皮功能（平均值±标准差）为32.7±6。分别为9年和1.8±0.5。与未治疗相比，二甲双胍治疗3个月后内皮功能未见明显变化。但是，在根据基线内皮功能对接受二甲双胍治疗的受试者进行分层后，二甲双胍治疗后基线内皮功能异常的受试者有显着改善（1.3±0.3 vs 1.7±0.3； P <.001），而基线正常的受试者则没有内皮功能（2.1±0.4 vs 2.0±0.5; P = .11）。结论二甲双胍可改善患有PCOS的女性的内皮功能和内皮功能障碍，而与葡萄糖代谢，血脂异常或糖尿病前期的变化无关。二甲双胍对PCOS中的内皮功能有直接影响，对内皮功能的测量可以分层并跟踪PCOS中对二甲双胍治疗的反应。