Insulin resistance in obesity and polycystic ovary syndrome: systematic review and meta-analysis of observational studies

Abstract

We aimed at investigating whether insulin resistance (IR)/sensitivity are impaired in obese/non-obese polycystic ovary syndrome (PCOS) and obese/non-obese healthy controls. A comprehensive literature search was performed for observational, English language studies. Meta-analysis was performed with the random effects model according to the heterogeneity. Eligible studies, involving 3037 women in four groups of: 1-obese, PCOS; 2-non-obese, PCOS, 3-obese, non-PCOS and 4-Non-obese, non-PCOS were included. Based on the insulin resistance index (HOMA-IR) analysis, the pooled mean (95% Conf. Interval) of HOMA IR in groups 1–4 were 4.38 (3.84, 4.92), 2.68 (2.16, 3.20), 2.44 (2.06, 2.82) and 1.34 (1.06, 1.63), respectively. Meta-analysis showed that group 1 (obese, PCOS patients) statistically have the highest IR and group 4 (non-obese, non-PCOS women) have the highest insulin sensitivity. Group 2 (non-obese, PCOS patients) and group 3 (obese, non-PCOS women) were between this range and they had lower IR than group 1 (obese, PCOS) and lower insulin sensitivity than group 4 (non-obese, non-PCOS). So, there were statistical differences between all groups except between groups 2 and 3. Insulin sensitivity indexes (quickie and ISI), also confirm the IR index (HOMA-IR) results. Based on different IR/sensitivity indexes, we found no evidence of any different effects of BMI ≥ 30 kg/m² on IR/sensitivity. In conclusion, PCOS status intensifies the adverse effects of obesity on IR, it has to be appropriately addressed in primary and secondary preventive cares and treatments provided for these women.

Chinese abstract

本研究旨在探讨肥胖/非肥胖多囊卵巢综合征（polycystic ovary syndrome, PCOS）患者和肥胖/非肥胖健康对照人群中胰岛素抵抗（insulin resistance, IR）/敏感性是否受损。我们对观察性研究英文文献进行了全面的检索。采用随机效应模型根据异质性进行meta分析。符合条件的研究包括3037名患者。分成4组：1.肥胖PCOS患者；2.非肥胖PCOS患者；3.非PCOS肥胖患者；4.非PCOS非肥胖患者。根据胰岛素抵抗指数（insulin resistance index, HOMA-IR）分析，1-4组HOMA-IR均值（95%置信区间）分别为4.38 (3.84, 4.92)，2.68 (2.16, 3.20)，2.44 (2.06, 2.82) and 1.34 (1.06, 1.63)。meta分析显示组1（肥胖，PCOS患者）IR程度最高，而组4（非肥胖非PCOS患者）胰岛素敏感性最高。组2（非肥胖，PCOS）和组3（肥胖，非PCOS）排在中等位置，较组1（肥胖，PCOS）的IR低，较组4（非肥胖，非PCOS）的胰岛素敏感程度低。因此，除组2和组3外，各组间差异均有统计学意义。胰岛素敏感指数（quickie和ISI）也可以证实IR指数（HOMA-IR）的结果。根据不同的IR指数和敏感指数，我们未发现BMI≥30 kg/m²对IR和敏感性有任何影响。总之，PCOS状态加剧了肥胖对IR的不良作用，对于这些患者，应当给予适当的主要和次要的预防和治疗。

• Insulin resistance
• meta-analysis
• obesity
• polycystic ovary syndrome

Acknowledgements

This study was financially supported by Reproductive Endocrinology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Declaration of interest

The authors report no declarations of interest.