Abstract: Objective To investigate the relationship between red blood cell distribution width （RDW） level and high-sensitivity C-reactive protein （hs-CRP）, homeostasis model assessment of insulin resistance（HOMA-IR）, Body Mass Index（BMI） and body fat percentage in patients with polycystic ovary syndrome（PCOS）, and analyze the clinical application value of RDW in PCOS. Methods A total of 136 patients with PCOS and 100 healthy women were enrolled as observation group and control group from January 2018 to September 2019. The clinical and laboratory data of the two groups were compared. Correlation was analyzed between RDW and laboratory parameters in the PCOS group. Receiver operating characteristic curve （ROC） analysis were used to compare the diagnostic value of RDW and testosterone for PCOS. Results The level of RDW in PCOS was significantly higher than that in the control group（13.22±1.37 vs. 12.61±0.79, P<0.001）. RDW levels were positively correlated with hs-CRP, HOMA-IR and BMI, but the correlation was not high. ROC curve analysis showed that the sensitivity of RDW diagnosis of PCOS （78.68% vs. 70.59%）and specificity （79.0% vs. 68.0%） were higher than testosterone, and the area under the curve（AUC）was statistically significant（P<0.05）. Conclusions Women with PCOS have higher levels of RDW and may be associated with potential chronic inflammation in PCOS patients.

Key words: Polycystic ovary syndrome, Red blood cell distribution width, Insulin resistance, Inflammation