Research On Insulin Resistance In Polycystic Ovary Syndrome Patients

Polycystic ovary syndrome(PCOS)is a common endocrine disease among adolescent and reproductive-age women.PCOS is currently diagnosed with the use of the2003 Rotterdam Criteria based on the presence of at least two of the following conditions:1)oligoamenorrhea and/or anovulation;2)hyperandrogenism(clinical and/or biochemical);and 3)polycystic ovary on ultrasound examination.In addition to these gynecologic symptoms,PCOS is often characterized by several metabolic disorders.Nowadays,the etiology of polycystic ovary syndrome is still been explored.Particular emphasis is placed on the presence of insulin resistance(IR)based on numerous researches and insulin resistance is believed to an important element in polycystic ovary syndrome pathophysiology.Interestingly,insulin resistance is recognized as part of a complex syndrome associated with increased cardiovascular risk,when it can result in abnormal glucose tolerance,dyslipidemia endothelial dysfunction and other complications.Furthermore,it become more and more significance to analyze and comprehend the genesis and progression of insulin resistance.Thus,we can predict and evaluate PCOS patients’IR in the early time.Our study was to investigate the characteristic of insulin resistance in PCOS patients.There were four parts in our study:1)A clinical analysis of glucose metabolism status in PCOS patients;2)Analysis of glucose and lipid metabolism indexes in patients with normal glucose tolerance and polycystic ovary syndrome;3)A new assessment research on insulin resistance in polycystic ovary syndrome patient;4)The value of serum free testosterone for the diagnosis of polycystic ovary syndrome in Chinese patients.PART I A Clinical Analysis of Glucose Metabolism Status in PCOS PatientsObjective To investigate the screening for hyperglycemia by oral glucose tolerance test in polycystic ovary syndrome(PCOS)patients and discuss the clinical features of glucose and lipid metabolism in different glucose metabolism status.Methods Height,weight,basal sexual hormones and lipid parameters,OGTT and insulin release test were measured from 191 women with PCOS according to Rotterdam consensus.Body mass index(BMI),HOMA-IR and HOMA-βet.al were calculated.PCOS patients were divided into normal glucose test(NGT)group,impaired fasting glucose(IFG)group,impaired glucose tolerance(IGT)group and type 2 diabetes mellitus(T2DM)group based on OGTT results.The glucose metabolism indexes and lipid metabolism indexes among the groups were also compared.Results In the 191 PCOS patients,24.61%of patients had abnormal glucose metabolism.The ratio of IFG,IGT and T2DM were 3.66%,18.85%and 4.19%respectively.The degree of impaired glucose metabolism increased correlated positively with the age and BMI.The insulin peak occurred at 2h,which was 1h later than glucose peak time point.With the aggravation of glucose metabolism,the glucose level and insulin level gradually increased.And the abnormality of lipid was in accordance with intensifying hyperglycemia.Conclusion Women with PCOS had a greater incidence of hyperglycemia.OGTT should be recommended in all individuals with PCOS.PART II Analysis of glucose and lipid metabolism indexes in patients with normal glucose tolerance and polycystic ovary syndromeObjective To investigate the glucose and lipid metabolism indexes in patients with normal glucose tolerance and polycystic ovary syndrome(PCOS).Methods One hundred and forty-four patients with PCOS were diagnosed according to Rotterdam criterion and undertaken oral glucose tolerance test(OGTT)and insulin release test(IRT),while one hundred healthy women with normal menstrual cycle served as controls.Results Compared with healthy controls,PCOS patients with normal glucose tolerance had a higher BMI,0min,30min,60 min serum glucose and insulin,HOMA-IR and the area under curve of glucose and insulin(P<0.05).Additionally,subgroup analysis was employed based on BMI,the obese group(BMI≥25kg/m~2)had a higher,0min,60min,120 min serum glucose and insulin level,HOMA-IR and TG than non-obese group(P<0.05),indicating that the ability of glucose and lipid metabolism in obese PCOS patients was still poor though they were with normal glucose tolerance after OGTT.Conclusion There was significant difference between the normal glucose tolerance PCOS patients and healthy controls.Insulin release test should be performed to observe the insulin resistance and take steps in advance.For those obese PCOS patients with normal glucose tolerance,more attention should be paid on the examination and follow-up of the insulin and lipid level.PART III A new assessment research on insulin resistance in polycystic ovary syndrome patientObjective To investigate a new assessment on insulin resistance(IR)based on different BMI polycystic ovary syndrome(PCOS)patients.Method A sum of 186 PCOS patients diagnosed according to Rotterdam criterion with normal glycometabolism and 84 healthy controls were enrolled in our research.All of them were undertaken oral glucose tolerance test(OGTT)and insulin release test(IRT)in order to be calculated the value of HOMA-My on different time point.We applied the receiver operating characteristic curve(ROC)to analyze the predictivity of HOMA-My based on normal-weight and obese patients.Result The level of sex hormone binding globulin(SHBG)and17-hydroxyprogesterone(17-OHP)were significant different between normal-weight and obese subgroup.HOMA-M30 was the best parameter(Cutoff:32.17,AUC:88.3%)to reflect IR in normal-weight patients while HOMA-IR was the worse.In obese PCOS person,HOMA-IR(cutoff:2.67)was slightly secondary to HOMA-M60,with 88.3%and87.6%ACU.Conclusion Our study provided a new method to evaluate IR in PCOS group.We suggested that HOMA-IR in normal-weight PCOS patients cannot stand up,and we should focus on HOMA-M3O and other time-point values together.As for obese subgroup,HOMA-IR was still recommended for clinicians and the cutoff value is 2.67.PART IV The Value of Serum Free Testosterone for the Diagnosis of Polycystic Ovary Syndrome in Chinese PatientsObjective To explore the value of total testosterone(TT)and free testosterone(FT)for the diagnosis of hyperandrogenism in polycystic ovary syndrome(PCOS)patients and analyze the correlation of Insulin resistance(IR).Methods Height,weight,basal sexual hormones and free testosterone(FT),fasting glucose(FPG)and fasting insulin(FINS)were collected from 365 women with PCOS according to Rotterdam consensus.The correlation and difference between TT and FT were analyzed,as well as the comparison with BMI,insulin resistance.Results Serum FT had a linear correlation with serum TT(r=0.660,r~2=0.448,P<0.001).Compared with TT,FT was more sensitive for the diagnosis of hyperandrogenemia significantly(14.61%vs.22.75%,p<0.05)and reflect the insulin resistance(r=0.213,P=0.002 vs.r=0.354,P=0.00)Conclusion FT is superior to TT in the hyperandrogenism for PCOS patients,and it is an ideal biochemical indicator to predict insulin sensitivity as well.