Progression of glucose intolerance and cardiometabolic risk factors over a decade in Chinese women with polycystic ovary syndrome: A case-control study.

Background Polycystic ovary syndrome (PCOS) is associated with increased metabolic risk, though data on long-term follow-up of cardiometabolic traits are limited. We postulated that Chinese women with PCOS would have higher risk of incident diabetes and cardiometabolic abnormalities than those without PCOS during long-term follow-up. Methods and findings One hundred ninety-nine Chinese women with PCOS diagnosed by the Rotterdam criteria and with a mean age of 41.2 years (SD = 6.4) completed a follow-up evaluation after an average of 10.6 1.3 years. Two hundred twenty-five women without PCOS (mean age: 54.1 6.7 years) who underwent baseline and follow-up evaluation over the same period were used for comparison. Progression of glycaemic status of women both with and without PCOS was assessed by using 75-g oral glucose tolerance test (OGTT) screening with the adoption of 2009 American Diabetes Association diagnostic criteria. The frequency of impaired glucose regulation, hypertension, and hyperlipidaemia of women with PCOS at follow-up has increased from 31.7% (95% CI 25.2%-38.1%) to 47.2% (95% CI 40.3%-54.2%), 16.1% (95% CI 11.0%-21.2%) to 34.7% (95% CI 28.1%-41.3%), and 52.3% (95% CI 45.3%-59.2%) to 64.3% (95% CI 57.7%-71.0%), respectively. The cumulative incidence of diabetes mellitus (DM) in follow-up women with PCOS is 26.1% (95% CI 20.0%-32.2%), almost double that in the cohort of women without PCOS (p < 0.001). Age-standardised incidence of diabetes among women with PCOS was 22.12 per 1,000 person-years (95% CI 10.86-33.37) compared with the local female population incidence rate of 8.76 per 1,000 person-years (95% CI 8.72-8.80) and 10.09 per 1,000 person-years (95% CI 4.92-15.26, p < 0.001) for women without PCOS in our study. Incidence rate for women with PCOS aged 30-39 years was 20.56 per 1,000 person-years (95% CI 12.57-31.87), which is approximately 10-fold higher than that of the age-matched general female population in Hong Kong (1.88 per 1,000 person-years, [95% CI 1.85-1.92]). The incidence rate of type 2 DM (T2DM) of both normal-weight and overweight women with PCOS was around double that of corresponding control groups (normal weight: 8.96 [95% CI 3.92-17.72] versus 4.86 per 1,000 person-years [95% CI 2.13-9.62], p > 0.05; overweight/obese: 28.64 [95% CI 19.55-40.60] versus 14.1 per 1,000 person-years [95% CI 8.20-22.76], p < 0.05). Logistic regression analysis identified that baseline waist-to-hip ratio (odds ratio [OR] = 1.71 [95% CI 1.08-2.69], p < 0.05) and elevated triglyceride (OR = 6.63 [95% CI 1.23-35.69], p < 0.05) are associated with the progression to T2DM in PCOS. Limitations of this study include moderate sample size with limited number of incident diabetes during follow-up period and potential selection bias. Conclusions High risk of diabetes and increased cardiovascular disease risk factors among Chinese women with PCOS are highlighted in this long-term follow-up study. Diabetes onset was, on average, 10 years earlier among women with PCOS than in women without PCOS. Author summary Why was this study done? Besides reproductive abnormality, it is known that women with polycystic ovary syndrome (PCOS) are at high risk of metabolic complications, such as insulin resistance (IR), impaired glucose tolerance (IGT), and type 2 diabetes mellitus (T2DM). The majority of the accessible longitudinal studies regarding the progression of T2DM in women with PCOS are from the United States, Australia, and Europe. Previous studies have mainly relied on self-report of diabetes status or linkage through national patient registries, which might underestimate the prevalence and incident rate of T2DM in women with PCOS. What did the researchers do and find? During 2016-2017, we prospectively investigated the progression of glycaemic status among 199 Chinese women with PCOS and compared the data with those of 242 women without PCOS by using oral glucose tolerance test (OGTT) for comprehensive glycaemic status screening. We found that the age-standardised incidence rate of T2DM among women with PCOS was around 2.5-fold higher compared with the local female population incidence rate. We noted that the incidence rate of T2DM of both normal-weight and overweight women with PCOS was around double that of respective control groups. This is a key controversial area in international literature and differs from data on individuals of European descent. Diabetes onset was, on average, 10 years earlier among women with PCOS than in women without PCOS. Chinese women with PCOS were at 6-fold higher risk of developing T2DM compared with those without PCOS. High waist-to-hip ratio (WHR), elevated triglyceride, and presence of hyperandrogenism are associated with the progression to T2DM in PCOS. What do these findings mean? This study highlighted the risk of diabetes and metabolic abnormalities in women with PCOS. The study has shed some light on the potential burden of young-onset diabetes associated with PCOS. This work has already been considered in the recent international guidelines, suggesting the clinical relevance of this work. Our data provide useful insights that universal screening should be considered in all Chinese adult women with PCOS. Our data suggested WHR, elevated triglyceride, and hyperandrogenism are associated with the progression to T2DM in PCOS, although we were unable to explore relationships with IR. Therefore, further research is clearly warranted.